mirror of https://gitee.com/openkylin/linux.git
591 Commits
| Author | SHA1 | Message | Date |
|---|---|---|---|
Linus Torvalds
|
335ad94c21 |
Misc changes:
- Prepare for Intel's new SERIALIZE instruction - Enable split-lock debugging on more CPUs - Add more Intel CPU models - Optimize stack canary initialization a bit - Simplify the Spectre logic a bit Signed-off-by: Ingo Molnar <mingo@kernel.org> -----BEGIN PGP SIGNATURE----- iQJFBAABCgAvFiEEBpT5eoXrXCwVQwEKEnMQ0APhK1gFAl8oTsQRHG1pbmdvQGtl cm5lbC5vcmcACgkQEnMQ0APhK1gueQ//Vh9sTi8+q5ZCxXnJQOi59SZsFy1quC2Q 6bFoSQ46npMBoYyC2eDQ4exBncWLqorT8Vq/evlW3XPldUzHKOk7b4Omonwyrrj5 dg5fqcRjpjU8ni6egmy4ElMjab53gDuv0yNazjONeBGeWuBGu4vI2bP2eY3Addfm 2eo2d5ZIMRCdShrUNwToJWWt6q4DzL/lcrVZAlX0LwlWVLqUCdIARALRM7V1XDsC udxS8KnvhTaJ7l63BSJREe3AGksLQd9P4UkJS4IE4t0zINBIrME043BYBMTh2Vvk y3jykKegIbmhPquGXG8grJbPDUF2/3FxmGKTIhpoo++agb2fxt921y5kqMJwniNS H/Gk032iGzjjwWnOoWE56UeuDTOlweSIrm4EG22HyEDK7kOMJusjYAV5fB4Sv7vj TBy5q0PCIutjXDTL1hIWf0WDiQt6eGNQS/yt3FlapLBGVRQwMU/pKYVVIOIaFtNs szx1ZeiT358Ww8a2fQlb8pqv50Upmr2wqFkAsMbm+NN3N92cqK6gJlo1p7fnxIuG +YVASobjsqbn0S62v/9SB/KRJz07adlZ6Tl/O/ILRvWyqik7COCCHDVJ62Zzaz5z LqR2daVM5H+Lp6jGZuIoq/JiUkxUe2K990eWHb3PUpOC4Rh73PvtMc7WFhbAjbye XV3eOEDi65c= =sL2Q -----END PGP SIGNATURE----- Merge tag 'x86-cpu-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 cpu updates from Ingo Molar: - prepare for Intel's new SERIALIZE instruction - enable split-lock debugging on more CPUs - add more Intel CPU models - optimize stack canary initialization a bit - simplify the Spectre logic a bit * tag 'x86-cpu-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/cpu: Refactor sync_core() for readability x86/cpu: Relocate sync_core() to sync_core.h x86/cpufeatures: Add enumeration for SERIALIZE instruction x86/split_lock: Enable the split lock feature on Sapphire Rapids and Alder Lake CPUs x86/cpu: Add Lakefield, Alder Lake and Rocket Lake models to the to Intel CPU family x86/stackprotector: Pre-initialize canary for secondary CPUs x86/speculation: Merge one test in spectre_v2_user_select_mitigation() |
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Brian Gerst
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c9a1ff316b |
x86/stackprotector: Pre-initialize canary for secondary CPUs
The idle tasks created for each secondary CPU already have a random stack canary generated by fork(). Copy the canary to the percpu variable before starting the secondary CPU which removes the need to call boot_init_stack_canary(). Signed-off-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200617225624.799335-1-brgerst@gmail.com |
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Giovanni Gherdovich
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f4291df103 |
x86, sched: Bail out of frequency invariance if turbo_freq/base_freq gives 0
Be defensive against the case where the processor reports a base_freq
larger than turbo_freq (the ratio would be zero).
Fixes:
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Giovanni Gherdovich
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51beea8862 |
x86, sched: Bail out of frequency invariance if turbo frequency is unknown
There may be CPUs that support turbo boost but don't declare any turbo
ratio, i.e. their MSR_TURBO_RATIO_LIMIT is all zeroes. In that condition
scale-invariant calculations can't be performed.
Fixes:
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Giovanni Gherdovich
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e2b0d619b4 |
x86, sched: check for counters overflow in frequency invariant accounting
The product mcnt * arch_max_freq_ratio can overflows u64.
For context, a large value for arch_max_freq_ratio would be 5000,
corresponding to a turbo_freq/base_freq ratio of 5 (normally it's more like
1500-2000). A large increment frequency for the MPERF counter would be 5GHz
(the base clock of all CPUs on the market today is less than that). With
these figures, a CPU would need to go without a scheduler tick for around 8
days for the u64 overflow to happen. It is unlikely, but the check is
warranted.
Under similar conditions, the difference acnt of two consecutive APERF
readings can overflow as well.
In these circumstances is appropriate to disable frequency invariant
accounting: the feature relies on measures of the clock frequency done at
every scheduler tick, which need to be "fresh" to be at all meaningful.
A note on i386: prior to version 5.1, the GCC compiler didn't have the
builtin function __builtin_mul_overflow. In these GCC versions the macro
check_mul_overflow needs __udivdi3() to do (u64)a/b, which the kernel
doesn't provide. For this reason this change fails to build on i386 if
GCC<5.1, and we protect the entire frequency invariant code behind
CONFIG_X86_64 (special thanks to "kbuild test robot" <lkp@intel.com>).
Fixes:
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Mike Rapoport
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65fddcfca8 |
mm: reorder includes after introduction of linux/pgtable.h
The replacement of <asm/pgrable.h> with <linux/pgtable.h> made the include
of the latter in the middle of asm includes. Fix this up with the aid of
the below script and manual adjustments here and there.
import sys
import re
if len(sys.argv) is not 3:
print "USAGE: %s <file> <header>" % (sys.argv[0])
sys.exit(1)
hdr_to_move="#include <linux/%s>" % sys.argv[2]
moved = False
in_hdrs = False
with open(sys.argv[1], "r") as f:
lines = f.readlines()
for _line in lines:
line = _line.rstrip('
')
if line == hdr_to_move:
continue
if line.startswith("#include <linux/"):
in_hdrs = True
elif not moved and in_hdrs:
moved = True
print hdr_to_move
print line
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200514170327.31389-4-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Mike Rapoport
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ca5999fde0 |
mm: introduce include/linux/pgtable.h
The include/linux/pgtable.h is going to be the home of generic page table manipulation functions. Start with moving asm-generic/pgtable.h to include/linux/pgtable.h and make the latter include asm/pgtable.h. Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Cain <bcain@codeaurora.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Zankel <chris@zankel.net> Cc: "David S. Miller" <davem@davemloft.net> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greentime Hu <green.hu@gmail.com> Cc: Greg Ungerer <gerg@linux-m68k.org> Cc: Guan Xuetao <gxt@pku.edu.cn> Cc: Guo Ren <guoren@kernel.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ley Foon Tan <ley.foon.tan@intel.com> Cc: Mark Salter <msalter@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Simek <monstr@monstr.eu> Cc: Nick Hu <nickhu@andestech.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Richard Weinberger <richard@nod.at> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Stafford Horne <shorne@gmail.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vincent Chen <deanbo422@gmail.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Will Deacon <will@kernel.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Link: http://lkml.kernel.org/r/20200514170327.31389-3-rppt@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Linus Torvalds
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17e0a7cb6a |
Misc cleanups, with an emphasis on removing obsolete/dead code.
Signed-off-by: Ingo Molnar <mingo@kernel.org> -----BEGIN PGP SIGNATURE----- iQJFBAABCgAvFiEEBpT5eoXrXCwVQwEKEnMQ0APhK1gFAl7VLcQRHG1pbmdvQGtl cm5lbC5vcmcACgkQEnMQ0APhK1iFnhAArGBqco3C2RPQugv7UDDbKEaMvxOGrc5B kwnyOS/k/yeIkfhT9u11oBuLcaj/Zgw8YCjFyRfaNsorRqnytLyZzZ6PvdCCE3YU X3DVYgulcdAQnM4bS2e3Kt9ciJvFxB27XNm0AfuyLMUxMqCD+iIO4gJ6TuQNBYy3 dfUMfB1R9OUDW13GCrASe+p1Dw76uaqVngdFWJhnC8Rm49E6gFXq7CLQp5Cka81I KZeJ8I6ug9p3gqhOIXdi+S6g5CM5jf86Wkk7dOHwHFH7CceFb3FIz7z0n1je4Wgd L5rYX7+PwfNeZ73GIuvEBN+agJH2K0H/KmnlWNWeZHzc+J12MeruSdSMBIkBOEpn iSbYAOmDpQLzBjTdZjC8bDqTZf472WrTh4VwN9NxHLucjdC+IqGoTAvnyyEOmZ5o R7sv7Q++316CVwRhYVXbzwZcqtiinCDE1EkP5nKTo9z3z0kMF5+ce/k7wn5sgZIk zJq3LXtaToiDoDRAPGxcvFPts9MdC0EI1aKTIjaK/n6i2h/SpJfrTKgANWaldYTe XJIqlSB43saqf5YAQ3/sY+wnpCRBmmCU+sfKja4C8bH7RuggI3mZS19uhFs0Qctq Yx5bIXVSBAIqjJtgzQ0WAAZ5LrCpNNyAzb35ZYefQlGyJlx1URKXVBmxa6S99biU KiYX7Dk5uhQ= =0ZQd -----END PGP SIGNATURE----- Merge tag 'x86-cleanups-2020-06-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 cleanups from Ingo Molnar: "Misc cleanups, with an emphasis on removing obsolete/dead code" * tag 'x86-cleanups-2020-06-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/spinlock: Remove obsolete ticket spinlock macros and types x86/mm: Drop deprecated DISCONTIGMEM support for 32-bit x86/apb_timer: Drop unused declaration and macro x86/apb_timer: Drop unused TSC calibration x86/io_apic: Remove unused function mp_init_irq_at_boot() x86/mm: Stop printing BRK addresses x86/audit: Fix a -Wmissing-prototypes warning for ia32_classify_syscall() x86/nmi: Remove edac.h include leftover mm: Remove MPX leftovers x86/mm/mmap: Fix -Wmissing-prototypes warnings x86/early_printk: Remove unused includes crash_dump: Remove no longer used saved_max_pfn x86/smpboot: Remove the last ICPU() macro |
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Linus Torvalds
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d861f6e682 |
Misc cleanups in the SMP hotplug and cross-call code.
Signed-off-by: Ingo Molnar <mingo@kernel.org> -----BEGIN PGP SIGNATURE----- iQJFBAABCgAvFiEEBpT5eoXrXCwVQwEKEnMQ0APhK1gFAl7VJfsRHG1pbmdvQGtl cm5lbC5vcmcACgkQEnMQ0APhK1ihcA/+Ko18kdGRPAlShM9qkDWO5N80p1LEp7F0 ku1OxPAz9ii7K/jlnGr9wYYPxsIL3lbFeqFE7q5q5socXufaN8MUj9sVCmN7ScmR zO84aTHtxrJJhKIPM6HkUTbVl5KrQaud3F/J56CCjuKPsJWy9iuCGnKtfKK38bx+ qJEfVKVm95Bv0NSEvqvci3DKKPYjzpKzuuttHXQ8Z80zG94FEkwj0JwZzttIjLl1 rgRMgWTH7+3tQCMnZEfXG8xBxbXS9i3hKyr/v5QTNgIICyXGquPkf5MiwjJFS2Xb wpPqNh8HTo5kUJstYygRjcftatU7K72h2Rz/CoUkN2roNYlvRAhdBaBMwN0cGaG8 pPhnLHHHRYZjl4fiROgRwVV3A6LcAHSrIcKzwGrvpCSpqyVozPGsmD/e8ZG1JYpC vxESTZbCDywng2Ls8jqQBut+dFGElvopXl1s004bCak89IFR4p15qojMJK2MSsqu BxhjIoqp8/f1fsAX+1p0RBEYnEr1KFtWa+nY8aVKL6bEx+Y7Qyq0ypMGtKavP06X VMcPMm1gYeXoGpLaTLYBRL5t7Rmm7i+xufuDQKUJetenfh2YS4aQ9lfV+rsQH1YE wavQrbwThfBZ9K1XkEmOkSqONysZ2YAtK9slKzciQIZvY3V8NbKAmBudCgqTgarp xqeW9NFfeFc= =Rr2n -----END PGP SIGNATURE----- Merge tag 'smp-core-2020-06-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull SMP updates from Ingo Molnar: "Misc cleanups in the SMP hotplug and cross-call code" * tag 'smp-core-2020-06-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: cpu/hotplug: Remove __freeze_secondary_cpus() cpu/hotplug: Remove disable_nonboot_cpus() cpu/hotplug: Fix a typo in comment "broadacasted"->"broadcasted" smp: Use smp_call_func_t in on_each_cpu() |
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Borislav Petkov
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a9a3ed1eff |
x86: Fix early boot crash on gcc-10, third try
... or the odyssey of trying to disable the stack protector for the function which generates the stack canary value. The whole story started with Sergei reporting a boot crash with a kernel built with gcc-10: Kernel panic — not syncing: stack-protector: Kernel stack is corrupted in: start_secondary CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.6.0-rc5—00235—gfffb08b37df9 #139 Hardware name: Gigabyte Technology Co., Ltd. To be filled by O.E.M./H77M—D3H, BIOS F12 11/14/2013 Call Trace: dump_stack panic ? start_secondary __stack_chk_fail start_secondary secondary_startup_64 -—-[ end Kernel panic — not syncing: stack—protector: Kernel stack is corrupted in: start_secondary This happens because gcc-10 tail-call optimizes the last function call in start_secondary() - cpu_startup_entry() - and thus emits a stack canary check which fails because the canary value changes after the boot_init_stack_canary() call. To fix that, the initial attempt was to mark the one function which generates the stack canary with: __attribute__((optimize("-fno-stack-protector"))) ... start_secondary(void *unused) however, using the optimize attribute doesn't work cumulatively as the attribute does not add to but rather replaces previously supplied optimization options - roughly all -fxxx options. The key one among them being -fno-omit-frame-pointer and thus leading to not present frame pointer - frame pointer which the kernel needs. The next attempt to prevent compilers from tail-call optimizing the last function call cpu_startup_entry(), shy of carving out start_secondary() into a separate compilation unit and building it with -fno-stack-protector, was to add an empty asm(""). This current solution was short and sweet, and reportedly, is supported by both compilers but we didn't get very far this time: future (LTO?) optimization passes could potentially eliminate this, which leads us to the third attempt: having an actual memory barrier there which the compiler cannot ignore or move around etc. That should hold for a long time, but hey we said that about the other two solutions too so... Reported-by: Sergei Trofimovich <slyfox@gentoo.org> Signed-off-by: Borislav Petkov <bp@suse.de> Tested-by: Kalle Valo <kvalo@codeaurora.org> Cc: <stable@vger.kernel.org> Link: https://lkml.kernel.org/r/20200314164451.346497-1-slyfox@gentoo.org |
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Qais Yousef
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5655585589 |
cpu/hotplug: Remove disable_nonboot_cpus()
The single user could have called freeze_secondary_cpus() directly. Since this function was a source of confusion, remove it as it's just a pointless wrapper. While at it, rename enable_nonboot_cpus() to thaw_secondary_cpus() to preserve the naming symmetry. Done automatically via: git grep -l enable_nonboot_cpus | xargs sed -i 's/enable_nonboot_cpus/thaw_secondary_cpus/g' Signed-off-by: Qais Yousef <qais.yousef@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Link: https://lkml.kernel.org/r/20200430114004.17477-1-qais.yousef@arm.com |
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Giovanni Gherdovich
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db441bd9f6 |
x86, sched: Move check for CPU type to caller function
Improve readability of the function intel_set_max_freq_ratio() by moving the check for KNL CPUs there, together with checks for GLM and SKX. Signed-off-by: Giovanni Gherdovich <ggherdovich@suse.cz> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Link: https://lkml.kernel.org/r/20200416054745.740-5-ggherdovich@suse.cz |
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Peter Zijlstra (Intel)
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b56e7d45e8 |
x86, sched: Don't enable static key when starting secondary CPUs
The static key arch_scale_freq_key only needs to be enabled once (at
boot). This change fixes a bug by which the key was enabled every time cpu0
is started, even as a secondary CPU during cpu hotplug. Secondary CPUs are
started from the idle thread: setting a static key from there means
acquiring a lock and may result in sleeping in the idle task, causing CPU
lockup.
Another consequence of this change is that init_counter_refs() is now
called on each CPU correctly; previously the function on_each_cpu() was
used, but it was called at boot when the only online cpu is cpu0.
[ggherdovich@suse.cz: Tested and wrote changelog]
Fixes:
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Giovanni Gherdovich
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23ccee22e8 |
x86, sched: Account for CPUs with less than 4 cores in freq. invariance
If a CPU has less than 4 physical cores, MSR_TURBO_RATIO_LIMIT will
rightfully report that the 4C turbo ratio is zero. In such cases, use the
1C turbo ratio instead for frequency invariance calculations.
Fixes:
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Giovanni Gherdovich
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9a6c2c3c7a |
x86, sched: Bail out of frequency invariance if base frequency is unknown
Some hypervisors such as VMWare ESXi 5.5 advertise support for
X86_FEATURE_APERFMPERF but then fill all MSR's with zeroes. In particular,
MSR_PLATFORM_INFO set to zero tricks the code that wants to know the base
clock frequency of the CPU (highest non-turbo frequency), producing a
division by zero when computing the ratio turbo_freq/base_freq necessary
for frequency invariant accounting.
It is to be noted that even if MSR_PLATFORM_INFO contained the appropriate
data, APERF and MPERF are constantly zero on ESXi 5.5, thus freq-invariance
couldn't be done in principle (not that it would make a lot of sense in a
VM anyway). The real problem is advertising X86_FEATURE_APERFMPERF. This
appears to be fixed in more recent versions: ESXi 6.7 doesn't advertise
that feature.
Fixes:
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Borislav Petkov
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2fa9a3cf30 |
x86/smpboot: Remove the last ICPU() macro
Now all is using the shiny new macros. No code changed: # arch/x86/kernel/smpboot.o: text data bss dec hex filename 16432 2649 40 19121 4ab1 smpboot.o.before 16432 2649 40 19121 4ab1 smpboot.o.after md5: a58104003b72c1de533095bc5a4c30a9 smpboot.o.before.asm a58104003b72c1de533095bc5a4c30a9 smpboot.o.after.asm Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20200324185836.GI22931@zn.tnic |
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Linus Torvalds
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fdf5563a72 |
Merge branch 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 cleanups from Ingo Molnar:
"This topic tree contains more commits than usual:
- most of it are uaccess cleanups/reorganization by Al
- there's a bunch of prototype declaration (--Wmissing-prototypes)
cleanups
- misc other cleanups all around the map"
* 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (36 commits)
x86/mm/set_memory: Fix -Wmissing-prototypes warnings
x86/efi: Add a prototype for efi_arch_mem_reserve()
x86/mm: Mark setup_emu2phys_nid() static
x86/jump_label: Move 'inline' keyword placement
x86/platform/uv: Add a missing prototype for uv_bau_message_interrupt()
kill uaccess_try()
x86: unsafe_put-style macro for sigmask
x86: x32_setup_rt_frame(): consolidate uaccess areas
x86: __setup_rt_frame(): consolidate uaccess areas
x86: __setup_frame(): consolidate uaccess areas
x86: setup_sigcontext(): list user_access_{begin,end}() into callers
x86: get rid of put_user_try in __setup_rt_frame() (both 32bit and 64bit)
x86: ia32_setup_rt_frame(): consolidate uaccess areas
x86: ia32_setup_frame(): consolidate uaccess areas
x86: ia32_setup_sigcontext(): lift user_access_{begin,end}() into the callers
x86/alternatives: Mark text_poke_loc_init() static
x86/cpu: Fix a -Wmissing-prototypes warning for init_ia32_feat_ctl()
x86/mm: Drop pud_mknotpresent()
x86: Replace setup_irq() by request_irq()
x86/configs: Slightly reduce defconfigs
...
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Linus Torvalds
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642e53ead6 |
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar:
"The main changes in this cycle are:
- Various NUMA scheduling updates: harmonize the load-balancer and
NUMA placement logic to not work against each other. The intended
result is better locality, better utilization and fewer migrations.
- Introduce Thermal Pressure tracking and optimizations, to improve
task placement on thermally overloaded systems.
- Implement frequency invariant scheduler accounting on (some) x86
CPUs. This is done by observing and sampling the 'recent' CPU
frequency average at ~tick boundaries. The CPU provides this data
via the APERF/MPERF MSRs. This hopefully makes our capacity
estimates more precise and keeps tasks on the same CPU better even
if it might seem overloaded at a lower momentary frequency. (As
usual, turbo mode is a complication that we resolve by observing
the maximum frequency and renormalizing to it.)
- Add asymmetric CPU capacity wakeup scan to improve capacity
utilization on asymmetric topologies. (big.LITTLE systems)
- PSI fixes and optimizations.
- RT scheduling capacity awareness fixes & improvements.
- Optimize the CONFIG_RT_GROUP_SCHED constraints code.
- Misc fixes, cleanups and optimizations - see the changelog for
details"
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (62 commits)
threads: Update PID limit comment according to futex UAPI change
sched/fair: Fix condition of avg_load calculation
sched/rt: cpupri_find: Trigger a full search as fallback
kthread: Do not preempt current task if it is going to call schedule()
sched/fair: Improve spreading of utilization
sched: Avoid scale real weight down to zero
psi: Move PF_MEMSTALL out of task->flags
MAINTAINERS: Add maintenance information for psi
psi: Optimize switching tasks inside shared cgroups
psi: Fix cpu.pressure for cpu.max and competing cgroups
sched/core: Distribute tasks within affinity masks
sched/fair: Fix enqueue_task_fair warning
thermal/cpu-cooling, sched/core: Move the arch_set_thermal_pressure() API to generic scheduler code
sched/rt: Remove unnecessary push for unfit tasks
sched/rt: Allow pulling unfitting task
sched/rt: Optimize cpupri_find() on non-heterogenous systems
sched/rt: Re-instate old behavior in select_task_rq_rt()
sched/rt: cpupri_find: Implement fallback mechanism for !fit case
sched/fair: Fix reordering of enqueue/dequeue_task_fair()
sched/fair: Fix runnable_avg for throttled cfs
...
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Thomas Gleixner
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adefe55e72 |
x86/kernel: Convert to new CPU match macros
The new macro set has a consistent namespace and uses C99 initializers instead of the grufty C89 ones. Get rid the of the local macro wrappers for consistency. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Link: https://lkml.kernel.org/r/20200320131509.250559388@linutronix.de |
|
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Martin Molnar
|
4d1d0977a2 |
x86: Fix a handful of typos
Fix a couple of typos in code comments. [ bp: While at it: s/IRQ's/IRQs/. ] Signed-off-by: Martin Molnar <martin.molnar.programming@gmail.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Randy Dunlap <rdunlap@infradead.org> Link: https://lkml.kernel.org/r/0819a044-c360-44a4-f0b6-3f5bafe2d35c@gmail.com |
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Giovanni Gherdovich
|
918229cdd5 |
x86/intel_pstate: Handle runtime turbo disablement/enablement in frequency invariance
On some platforms such as the Dell XPS 13 laptop the firmware disables turbo when the machine is disconnected from AC, and viceversa it enables it again when it's reconnected. In these cases a _PPC ACPI notification is issued. The scheduler needs to know freq_max for frequency-invariant calculations. To account for turbo availability to come and go, record freq_max at boot as if turbo was available and store it in a helper variable. Use a setter function to swap between freq_base and freq_max every time turbo goes off or on. Signed-off-by: Giovanni Gherdovich <ggherdovich@suse.cz> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Link: https://lkml.kernel.org/r/20200122151617.531-7-ggherdovich@suse.cz |
|
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Giovanni Gherdovich
|
298c6f99bf |
x86, sched: Add support for frequency invariance on ATOM
The scheduler needs the ratio freq_curr/freq_max for frequency-invariant accounting. On all ATOM CPUs prior to Goldmont, set freq_max to the 1-core turbo ratio. We intended to perform tests validating that this patch doesn't regress in terms of energy efficiency, given that this is the primary concern on Atom processors. Alas, we found out that turbostat doesn't support reading RAPL interfaces on our test machine (Airmont), and we don't have external equipment to measure power consumption; all we have is the performance results of the benchmarks we ran. Test machine: Platform : Dell Wyse 3040 Thin Client[1] CPU Model : Intel Atom x5-Z8350 (aka Cherry Trail, aka Airmont) Fam/Mod/Ste : 6:76:4 Topology : 1 socket, 4 cores / 4 threads Memory : 2G Storage : onboard flash, XFS filesystem [1] https://www.dell.com/en-us/work/shop/wyse-endpoints-and-software/wyse-3040-thin-client/spd/wyse-3040-thin-client Base frequency and available turbo levels (MHz): Min Operating Freq 266 |*** Low Freq Mode 800 |******** Base Freq 2400 |************************ 4 Cores 2800 |**************************** 3 Cores 2800 |**************************** 2 Cores 3200 |******************************** 1 Core 3200 |******************************** Tested kernels: Baseline : v5.4-rc1, intel_pstate passive, schedutil Comparison #1 : v5.4-rc1, intel_pstate active , powersave Comparison #2 : v5.4-rc1, this patch, intel_pstate passive, schedutil tbench, hackbench and kernbench performed the same under all three kernels; dbench ran faster with intel_pstate/powersave and the git unit tests were a lot faster with intel_pstate/powersave and invariant schedutil wrt the baseline. Not that any of this is terrbily interesting anyway, one doesn't buy an Atom system to go fast. Power consumption regressions aren't expected but we lack the equipment to make that measurement. Turbostat seems to think that reading RAPL on this machine isn't a good idea and we're trusting that decision. comparison ratio of performance with baseline; 1.00 means neutral, lower is better: I_PSTATE FREQ-INV ---------------------------------------- dbench 0.90 ~ kernbench 0.98 0.97 gitsource 0.63 0.43 Signed-off-by: Giovanni Gherdovich <ggherdovich@suse.cz> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Link: https://lkml.kernel.org/r/20200122151617.531-6-ggherdovich@suse.cz |
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Giovanni Gherdovich
|
eacf0474ae |
x86, sched: Add support for frequency invariance on ATOM_GOLDMONT*
The scheduler needs the ratio freq_curr/freq_max for frequency-invariant accounting. On GOLDMONT (aka Apollo Lake), GOLDMONT_D (aka Denverton) and GOLDMONT_PLUS CPUs (aka Gemini Lake) set freq_max to the highest frequency reported by the CPU. The encoding of turbo ratios for GOLDMONT* is identical to the one for SKYLAKE_X, but we treat the Atom case apart because we want to set freq_max to a higher value, thus the ratio freq_curr/freq_max to be lower, leading to more conservative frequency selections (favoring power efficiency). Signed-off-by: Giovanni Gherdovich <ggherdovich@suse.cz> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Link: https://lkml.kernel.org/r/20200122151617.531-5-ggherdovich@suse.cz |
|
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Giovanni Gherdovich
|
8bea0dfb4a |
x86, sched: Add support for frequency invariance on XEON_PHI_KNL/KNM
The scheduler needs the ratio freq_curr/freq_max for frequency-invariant
accounting. On Xeon Phi CPUs set freq_max to the second-highest frequency
reported by the CPU.
Xeon Phi CPUs such as Knights Landing and Knights Mill typically have either
one or two turbo frequencies; in the former case that's 100 MHz above the base
frequency, in the latter case the two levels are 100 MHz and 200 MHz above
base frequency.
We set freq_max to the second-highest frequency reported by the CPU. This
could be the base frequency (if only one turbo level is available) or the first
turbo level (if two levels are available). The rationale is to compromise
between power efficiency or performance -- going straight to max turbo would
favor efficiency and blindly using base freq would favor performance.
For reference, this is how MSR_TURBO_RATIO_LIMIT must be parsed on a Xeon Phi
to get the available frequencies (taken from a comment in turbostat's sources):
[0] -- Reserved
[7:1] -- Base value of number of active cores of bucket 1.
[15:8] -- Base value of freq ratio of bucket 1.
[20:16] -- +ve delta of number of active cores of bucket 2.
i.e. active cores of bucket 2 =
active cores of bucket 1 + delta
[23:21] -- Negative delta of freq ratio of bucket 2.
i.e. freq ratio of bucket 2 =
freq ratio of bucket 1 - delta
[28:24]-- +ve delta of number of active cores of bucket 3.
[31:29]-- -ve delta of freq ratio of bucket 3.
[36:32]-- +ve delta of number of active cores of bucket 4.
[39:37]-- -ve delta of freq ratio of bucket 4.
[44:40]-- +ve delta of number of active cores of bucket 5.
[47:45]-- -ve delta of freq ratio of bucket 5.
[52:48]-- +ve delta of number of active cores of bucket 6.
[55:53]-- -ve delta of freq ratio of bucket 6.
[60:56]-- +ve delta of number of active cores of bucket 7.
[63:61]-- -ve delta of freq ratio of bucket 7.
1. PERFORMANCE EVALUATION: TBENCH +5%
2. NEUTRAL BENCHMARKS (ALL OTHERS)
3. TEST SETUP
1. PERFORMANCE EVALUATION: TBENCH +5%
-------------------------------------
A performance evaluation was conducted on a Knights Mill machine (see "Test
Setup" below), were the frequency-invariance patch (on schedutil) is compared
to both non-invariant schedutil and active intel_pstate with powersave: all
three tested kernels behave the same performance-wise and with regard to power
consumption (performance per watt). The only notable difference is tbench:
comparison ratio of performance with baseline; 1.00 means neutral,
higher is better:
I_PSTATE FREQ-INV
----------------------------------------
tbench 1.04 1.05
performance-per-watt ratios with baseline; 1.00 means neutral, higher is better:
I_PSTATE FREQ-INV
----------------------------------------
tbench 1.03 1.04
which essentially means that frequency-invariant schedutil is 5% better than
baseline, the same as intel_pstate+powersave.
As the results above are averaged over the varying parameter, here the detailed
table.
Varying parameter : number of clients
Unit : MB/sec (higher is better)
5.2.0 vanilla (BASELINE) 5.2.0 intel_pstate 5.2.0 freq-inv
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Hmean 1 49.06 +- 2.12% ( ) 51.66 +- 1.52% ( 5.30%) 52.87 +- 0.88% ( 7.76%)
Hmean 2 93.82 +- 0.45% ( ) 103.24 +- 0.70% ( 10.05%) 105.90 +- 0.70% ( 12.88%)
Hmean 4 192.46 +- 1.15% ( ) 215.95 +- 0.60% ( 12.21%) 215.78 +- 1.43% ( 12.12%)
Hmean 8 406.74 +- 2.58% ( ) 438.58 +- 0.36% ( 7.83%) 437.61 +- 0.97% ( 7.59%)
Hmean 16 857.70 +- 1.22% ( ) 890.26 +- 0.72% ( 3.80%) 889.11 +- 0.73% ( 3.66%)
Hmean 32 1760.10 +- 0.92% ( ) 1791.70 +- 0.44% ( 1.79%) 1787.95 +- 0.44% ( 1.58%)
Hmean 64 3183.50 +- 0.34% ( ) 3183.19 +- 0.36% ( -0.01%) 3187.53 +- 0.36% ( 0.13%)
Hmean 128 4830.96 +- 0.31% ( ) 4846.53 +- 0.30% ( 0.32%) 4855.86 +- 0.30% ( 0.52%)
Hmean 256 5467.98 +- 0.38% ( ) 5793.80 +- 0.28% ( 5.96%) 5821.94 +- 0.17% ( 6.47%)
Hmean 512 5398.10 +- 0.06% ( ) 5745.56 +- 0.08% ( 6.44%) 5503.68 +- 0.07% ( 1.96%)
Hmean 1024 5290.43 +- 0.63% ( ) 5221.07 +- 0.47% ( -1.31%) 5277.22 +- 0.80% ( -0.25%)
Hmean 1088 5139.71 +- 0.57% ( ) 5236.02 +- 0.71% ( 1.87%) 5190.57 +- 0.41% ( 0.99%)
2. NEUTRAL BENCHMARKS (ALL OTHERS)
----------------------------------
* pgbench (both read/write and read-only)
* NASA Parallel Benchmarks (NPB), MPI or OpenMP for message-passing
* hackbench
* netperf
* dbench
* kernbench
* gitsource (git unit test suite)
3. TEST SETUP
-------------
Test machine:
CPU Model : Intel Xeon Phi CPU 7255 @ 1.10GHz (a.k.a. Knights Mill)
Fam/Mod/Ste : 6:133:0
Topology : 1 socket, 68 cores / 272 threads
Memory : 96G
Storage : rotary, XFS filesystem
Max EFFICiency, BASE frequency and available turbo levels (MHz):
EFFIC 1000 |**********
BASE 1100 |***********
68C 1100 |***********
30C 1200 |************
Tested kernels:
Baseline : v5.2, intel_pstate passive, schedutil
Comparison #1 : v5.2, intel_pstate active , powersave
Comparison #2 : v5.2, this patch, intel_pstate passive, schedutil
Signed-off-by: Giovanni Gherdovich <ggherdovich@suse.cz>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lkml.kernel.org/r/20200122151617.531-4-ggherdovich@suse.cz
|
|
|
Giovanni Gherdovich
|
2a0abc5969 |
x86, sched: Add support for frequency invariance on SKYLAKE_X
The scheduler needs the ratio freq_curr/freq_max for frequency-invariant
accounting. On SKYLAKE_X CPUs set freq_max to the highest frequency that can
be sustained by a group of at least 4 cores.
From the changelog of commit
|
|
|
Giovanni Gherdovich
|
1567c3e346 |
x86, sched: Add support for frequency invariance
Implement arch_scale_freq_capacity() for 'modern' x86. This function
is used by the scheduler to correctly account usage in the face of
DVFS.
The present patch addresses Intel processors specifically and has positive
performance and performance-per-watt implications for the schedutil cpufreq
governor, bringing it closer to, if not on-par with, the powersave governor
from the intel_pstate driver/framework.
Large performance gains are obtained when the machine is lightly loaded and
no regression are observed at saturation. The benchmarks with the largest
gains are kernel compilation, tbench (the networking version of dbench) and
shell-intensive workloads.
1. FREQUENCY INVARIANCE: MOTIVATION
* Without it, a task looks larger if the CPU runs slower
2. PECULIARITIES OF X86
* freq invariance accounting requires knowing the ratio freq_curr/freq_max
2.1 CURRENT FREQUENCY
* Use delta_APERF / delta_MPERF * freq_base (a.k.a "BusyMHz")
2.2 MAX FREQUENCY
* It varies with time (turbo). As an approximation, we set it to a
constant, i.e. 4-cores turbo frequency.
3. EFFECTS ON THE SCHEDUTIL FREQUENCY GOVERNOR
* The invariant schedutil's formula has no feedback loop and reacts faster
to utilization changes
4. KNOWN LIMITATIONS
* In some cases tasks can't reach max util despite how hard they try
5. PERFORMANCE TESTING
5.1 MACHINES
* Skylake, Broadwell, Haswell
5.2 SETUP
* baseline Linux v5.2 w/ non-invariant schedutil. Tested freq_max = 1-2-3-4-8-12
active cores turbo w/ invariant schedutil, and intel_pstate/powersave
5.3 BENCHMARK RESULTS
5.3.1 NEUTRAL BENCHMARKS
* NAS Parallel Benchmark (HPC), hackbench
5.3.2 NON-NEUTRAL BENCHMARKS
* tbench (10-30% better), kernbench (10-15% better),
shell-intensive-scripts (30-50% better)
* no regressions
5.3.3 SELECTION OF DETAILED RESULTS
5.3.4 POWER CONSUMPTION, PERFORMANCE-PER-WATT
* dbench (5% worse on one machine), kernbench (3% worse),
tbench (5-10% better), shell-intensive-scripts (10-40% better)
6. MICROARCH'ES ADDRESSED HERE
* Xeon Core before Scalable Performance processors line (Xeon Gold/Platinum
etc have different MSRs semantic for querying turbo levels)
7. REFERENCES
* MMTests performance testing framework, github.com/gormanm/mmtests
+-------------------------------------------------------------------------+
| 1. FREQUENCY INVARIANCE: MOTIVATION
+-------------------------------------------------------------------------+
For example; suppose a CPU has two frequencies: 500 and 1000 Mhz. When
running a task that would consume 1/3rd of a CPU at 1000 MHz, it would
appear to consume 2/3rd (or 66.6%) when running at 500 MHz, giving the
false impression this CPU is almost at capacity, even though it can go
faster [*]. In a nutshell, without frequency scale-invariance tasks look
larger just because the CPU is running slower.
[*] (footnote: this assumes a linear frequency/performance relation; which
everybody knows to be false, but given realities its the best approximation
we can make.)
+-------------------------------------------------------------------------+
| 2. PECULIARITIES OF X86
+-------------------------------------------------------------------------+
Accounting for frequency changes in PELT signals requires the computation of
the ratio freq_curr / freq_max. On x86 neither of those terms is readily
available.
2.1 CURRENT FREQUENCY
====================
Since modern x86 has hardware control over the actual frequency we run
at (because amongst other things, Turbo-Mode), we cannot simply use
the frequency as requested through cpufreq.
Instead we use the APERF/MPERF MSRs to compute the effective frequency
over the recent past. Also, because reading MSRs is expensive, don't
do so every time we need the value, but amortize the cost by doing it
every tick.
2.2 MAX FREQUENCY
=================
Obtaining freq_max is also non-trivial because at any time the hardware can
provide a frequency boost to a selected subset of cores if the package has
enough power to spare (eg: Turbo Boost). This means that the maximum frequency
available to a given core changes with time.
The approach taken in this change is to arbitrarily set freq_max to a constant
value at boot. The value chosen is the "4-cores (4C) turbo frequency" on most
microarchitectures, after evaluating the following candidates:
* 1-core (1C) turbo frequency (the fastest turbo state available)
* around base frequency (a.k.a. max P-state)
* something in between, such as 4C turbo
To interpret these options, consider that this is the denominator in
freq_curr/freq_max, and that ratio will be used to scale PELT signals such as
util_avg and load_avg. A large denominator will undershoot (util_avg looks a
bit smaller than it really is), viceversa with a smaller denominator PELT
signals will tend to overshoot. Given that PELT drives frequency selection
in the schedutil governor, we will have:
freq_max set to | effect on DVFS
--------------------+------------------
1C turbo | power efficiency (lower freq choices)
base freq | performance (higher util_avg, higher freq requests)
4C turbo | a bit of both
4C turbo proves to be a good compromise in a number of benchmarks (see below).
+-------------------------------------------------------------------------+
| 3. EFFECTS ON THE SCHEDUTIL FREQUENCY GOVERNOR
+-------------------------------------------------------------------------+
Once an architecture implements a frequency scale-invariant utilization (the
PELT signal util_avg), schedutil switches its frequency selection formula from
freq_next = 1.25 * freq_curr * util [non-invariant util signal]
to
freq_next = 1.25 * freq_max * util [invariant util signal]
where, in the second formula, freq_max is set to the 1C turbo frequency (max
turbo). The advantage of the second formula, whose usage we unlock with this
patch, is that freq_next doesn't depend on the current frequency in an
iterative fashion, but can jump to any frequency in a single update. This
absence of feedback in the formula makes it quicker to react to utilization
changes and more robust against pathological instabilities.
Compare it to the update formula of intel_pstate/powersave:
freq_next = 1.25 * freq_max * Busy%
where again freq_max is 1C turbo and Busy% is the percentage of time not spent
idling (calculated with delta_MPERF / delta_TSC); essentially the same as
invariant schedutil, and largely responsible for intel_pstate/powersave good
reputation. The non-invariant schedutil formula is derived from the invariant
one by approximating util_inv with util_raw * freq_curr / freq_max, but this
has limitations.
Testing shows improved performances due to better frequency selections when
the machine is lightly loaded, and essentially no change in behaviour at
saturation / overutilization.
+-------------------------------------------------------------------------+
| 4. KNOWN LIMITATIONS
+-------------------------------------------------------------------------+
It's been shown that it is possible to create pathological scenarios where a
CPU-bound task cannot reach max utilization, if the normalizing factor
freq_max is fixed to a constant value (see [Lelli-2018]).
If freq_max is set to 4C turbo as we do here, one needs to peg at least 5
cores in a package doing some busywork, and observe that none of those task
will ever reach max util (1024) because they're all running at less than the
4C turbo frequency.
While this concern still applies, we believe the performance benefit of
frequency scale-invariant PELT signals outweights the cost of this limitation.
[Lelli-2018]
https://lore.kernel.org/lkml/20180517150418.GF22493@localhost.localdomain/
+-------------------------------------------------------------------------+
| 5. PERFORMANCE TESTING
+-------------------------------------------------------------------------+
5.1 MACHINES
============
We tested the patch on three machines, with Skylake, Broadwell and Haswell
CPUs. The details are below, together with the available turbo ratios as
reported by the appropriate MSRs.
* 8x-SKYLAKE-UMA:
Single socket E3-1240 v5, Skylake 4 cores/8 threads
Max EFFiciency, BASE frequency and available turbo levels (MHz):
EFFIC 800 |********
BASE 3500 |***********************************
4C 3700 |*************************************
3C 3800 |**************************************
2C 3900 |***************************************
1C 3900 |***************************************
* 80x-BROADWELL-NUMA:
Two sockets E5-2698 v4, 2x Broadwell 20 cores/40 threads
Max EFFiciency, BASE frequency and available turbo levels (MHz):
EFFIC 1200 |************
BASE 2200 |**********************
8C 2900 |*****************************
7C 3000 |******************************
6C 3100 |*******************************
5C 3200 |********************************
4C 3300 |*********************************
3C 3400 |**********************************
2C 3600 |************************************
1C 3600 |************************************
* 48x-HASWELL-NUMA
Two sockets E5-2670 v3, 2x Haswell 12 cores/24 threads
Max EFFiciency, BASE frequency and available turbo levels (MHz):
EFFIC 1200 |************
BASE 2300 |***********************
12C 2600 |**************************
11C 2600 |**************************
10C 2600 |**************************
9C 2600 |**************************
8C 2600 |**************************
7C 2600 |**************************
6C 2600 |**************************
5C 2700 |***************************
4C 2800 |****************************
3C 2900 |*****************************
2C 3100 |*******************************
1C 3100 |*******************************
5.2 SETUP
=========
* The baseline is Linux v5.2 with schedutil (non-invariant) and the intel_pstate
driver in passive mode.
* The rationale for choosing the various freq_max values to test have been to
try all the 1-2-3-4C turbo levels (note that 1C and 2C turbo are identical
on all machines), plus one more value closer to base_freq but still in the
turbo range (8C turbo for both 80x-BROADWELL-NUMA and 48x-HASWELL-NUMA).
* In addition we've run all tests with intel_pstate/powersave for comparison.
* The filesystem is always XFS, the userspace is openSUSE Leap 15.1.
* 8x-SKYLAKE-UMA is capable of HWP (Hardware-Managed P-States), so the runs
with active intel_pstate on this machine use that.
This gives, in terms of combinations tested on each machine:
* 8x-SKYLAKE-UMA
* Baseline: Linux v5.2, non-invariant schedutil, intel_pstate passive
* intel_pstate active + powersave + HWP
* invariant schedutil, freq_max = 1C turbo
* invariant schedutil, freq_max = 3C turbo
* invariant schedutil, freq_max = 4C turbo
* both 80x-BROADWELL-NUMA and 48x-HASWELL-NUMA
* [same as 8x-SKYLAKE-UMA, but no HWP capable]
* invariant schedutil, freq_max = 8C turbo
(which on 48x-HASWELL-NUMA is the same as 12C turbo, or "all cores turbo")
5.3 BENCHMARK RESULTS
=====================
5.3.1 NEUTRAL BENCHMARKS
------------------------
Tests that didn't show any measurable difference in performance on any of the
test machines between non-invariant schedutil and our patch are:
* NAS Parallel Benchmarks (NPB) using either MPI or openMP for IPC, any
computational kernel
* flexible I/O (FIO)
* hackbench (using threads or processes, and using pipes or sockets)
5.3.2 NON-NEUTRAL BENCHMARKS
----------------------------
What follow are summary tables where each benchmark result is given a score.
* A tilde (~) means a neutral result, i.e. no difference from baseline.
* Scores are computed with the ratio result_new / result_baseline, so a tilde
means a score of 1.00.
* The results in the score ratio are the geometric means of results running
the benchmark with different parameters (eg: for kernbench: using 1, 2, 4,
... number of processes; for pgbench: varying the number of clients, and so
on).
* The first three tables show higher-is-better kind of tests (i.e. measured in
operations/second), the subsequent three show lower-is-better kind of tests
(i.e. the workload is fixed and we measure elapsed time, think kernbench).
* "gitsource" is a name we made up for the test consisting in running the
entire unit tests suite of the Git SCM and measuring how long it takes. We
take it as a typical example of shell-intensive serialized workload.
* In the "I_PSTATE" column we have the results for intel_pstate/powersave. Other
columns show invariant schedutil for different values of freq_max. 4C turbo
is circled as it's the value we've chosen for the final implementation.
80x-BROADWELL-NUMA (comparison ratio; higher is better)
+------+
I_PSTATE 1C 3C | 4C | 8C
pgbench-ro 1.14 ~ ~ | 1.11 | 1.14
pgbench-rw ~ ~ ~ | ~ | ~
netperf-udp 1.06 ~ 1.06 | 1.05 | 1.07
netperf-tcp ~ 1.03 ~ | 1.01 | 1.02
tbench4 1.57 1.18 1.22 | 1.30 | 1.56
+------+
8x-SKYLAKE-UMA (comparison ratio; higher is better)
+------+
I_PSTATE/HWP 1C 3C | 4C |
pgbench-ro ~ ~ ~ | ~ |
pgbench-rw ~ ~ ~ | ~ |
netperf-udp ~ ~ ~ | ~ |
netperf-tcp ~ ~ ~ | ~ |
tbench4 1.30 1.14 1.14 | 1.16 |
+------+
48x-HASWELL-NUMA (comparison ratio; higher is better)
+------+
I_PSTATE 1C 3C | 4C | 12C
pgbench-ro 1.15 ~ ~ | 1.06 | 1.16
pgbench-rw ~ ~ ~ | ~ | ~
netperf-udp 1.05 0.97 1.04 | 1.04 | 1.02
netperf-tcp 0.96 1.01 1.01 | 1.01 | 1.01
tbench4 1.50 1.05 1.13 | 1.13 | 1.25
+------+
In the table above we see that active intel_pstate is slightly better than our
4C-turbo patch (both in reference to the baseline non-invariant schedutil) on
read-only pgbench and much better on tbench. Both cases are notable in which
it shows that lowering our freq_max (to 8C-turbo and 12C-turbo on
80x-BROADWELL-NUMA and 48x-HASWELL-NUMA respectively) helps invariant
schedutil to get closer.
If we ignore active intel_pstate and focus on the comparison with baseline
alone, there are several instances of double-digit performance improvement.
80x-BROADWELL-NUMA (comparison ratio; lower is better)
+------+
I_PSTATE 1C 3C | 4C | 8C
dbench4 1.23 0.95 0.95 | 0.95 | 0.95
kernbench 0.93 0.83 0.83 | 0.83 | 0.82
gitsource 0.98 0.49 0.49 | 0.49 | 0.48
+------+
8x-SKYLAKE-UMA (comparison ratio; lower is better)
+------+
I_PSTATE/HWP 1C 3C | 4C |
dbench4 ~ ~ ~ | ~ |
kernbench ~ ~ ~ | ~ |
gitsource 0.92 0.55 0.55 | 0.55 |
+------+
48x-HASWELL-NUMA (comparison ratio; lower is better)
+------+
I_PSTATE 1C 3C | 4C | 8C
dbench4 ~ ~ ~ | ~ | ~
kernbench 0.94 0.90 0.89 | 0.90 | 0.90
gitsource 0.97 0.69 0.69 | 0.69 | 0.69
+------+
dbench is not very remarkable here, unless we notice how poorly active
intel_pstate is performing on 80x-BROADWELL-NUMA: 23% regression versus
non-invariant schedutil. We repeated that run getting consistent results. Out
of scope for the patch at hand, but deserving future investigation. Other than
that, we previously ran this campaign with Linux v5.0 and saw the patch doing
better on dbench a the time. We haven't checked closely and can only speculate
at this point.
On the NUMA boxes kernbench gets 10-15% improvements on average; we'll see in
the detailed tables that the gains concentrate on low process counts (lightly
loaded machines).
The test we call "gitsource" (running the git unit test suite, a long-running
single-threaded shell script) appears rather spectacular in this table (gains
of 30-50% depending on the machine). It is to be noted, however, that
gitsource has no adjustable parameters (such as the number of jobs in
kernbench, which we average over in order to get a single-number summary
score) and is exactly the kind of low-parallelism workload that benefits the
most from this patch. When looking at the detailed tables of kernbench or
tbench4, at low process or client counts one can see similar numbers.
5.3.3 SELECTION OF DETAILED RESULTS
-----------------------------------
Machine : 48x-HASWELL-NUMA
Benchmark : tbench4 (i.e. dbench4 over the network, actually loopback)
Varying parameter : number of clients
Unit : MB/sec (higher is better)
5.2.0 vanilla (BASELINE) 5.2.0 intel_pstate 5.2.0 1C-turbo
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Hmean 1 126.73 +- 0.31% ( ) 315.91 +- 0.66% ( 149.28%) 125.03 +- 0.76% ( -1.34%)
Hmean 2 258.04 +- 0.62% ( ) 614.16 +- 0.51% ( 138.01%) 269.58 +- 1.45% ( 4.47%)
Hmean 4 514.30 +- 0.67% ( ) 1146.58 +- 0.54% ( 122.94%) 533.84 +- 1.99% ( 3.80%)
Hmean 8 1111.38 +- 2.52% ( ) 2159.78 +- 0.38% ( 94.33%) 1359.92 +- 1.56% ( 22.36%)
Hmean 16 2286.47 +- 1.36% ( ) 3338.29 +- 0.21% ( 46.00%) 2720.20 +- 0.52% ( 18.97%)
Hmean 32 4704.84 +- 0.35% ( ) 4759.03 +- 0.43% ( 1.15%) 4774.48 +- 0.30% ( 1.48%)
Hmean 64 7578.04 +- 0.27% ( ) 7533.70 +- 0.43% ( -0.59%) 7462.17 +- 0.65% ( -1.53%)
Hmean 128 6998.52 +- 0.16% ( ) 6987.59 +- 0.12% ( -0.16%) 6909.17 +- 0.14% ( -1.28%)
Hmean 192 6901.35 +- 0.25% ( ) 6913.16 +- 0.10% ( 0.17%) 6855.47 +- 0.21% ( -0.66%)
5.2.0 3C-turbo 5.2.0 4C-turbo 5.2.0 12C-turbo
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Hmean 1 128.43 +- 0.28% ( 1.34%) 130.64 +- 3.81% ( 3.09%) 153.71 +- 5.89% ( 21.30%)
Hmean 2 311.70 +- 6.15% ( 20.79%) 281.66 +- 3.40% ( 9.15%) 305.08 +- 5.70% ( 18.23%)
Hmean 4 641.98 +- 2.32% ( 24.83%) 623.88 +- 5.28% ( 21.31%) 906.84 +- 4.65% ( 76.32%)
Hmean 8 1633.31 +- 1.56% ( 46.96%) 1714.16 +- 0.93% ( 54.24%) 2095.74 +- 0.47% ( 88.57%)
Hmean 16 3047.24 +- 0.42% ( 33.27%) 3155.02 +- 0.30% ( 37.99%) 3634.58 +- 0.15% ( 58.96%)
Hmean 32 4734.31 +- 0.60% ( 0.63%) 4804.38 +- 0.23% ( 2.12%) 4674.62 +- 0.27% ( -0.64%)
Hmean 64 7699.74 +- 0.35% ( 1.61%) 7499.72 +- 0.34% ( -1.03%) 7659.03 +- 0.25% ( 1.07%)
Hmean 128 6935.18 +- 0.15% ( -0.91%) 6942.54 +- 0.10% ( -0.80%) 7004.85 +- 0.12% ( 0.09%)
Hmean 192 6901.62 +- 0.12% ( 0.00%) 6856.93 +- 0.10% ( -0.64%) 6978.74 +- 0.10% ( 1.12%)
This is one of the cases where the patch still can't surpass active
intel_pstate, not even when freq_max is as low as 12C-turbo. Otherwise, gains are
visible up to 16 clients and the saturated scenario is the same as baseline.
The scores in the summary table from the previous sections are ratios of
geometric means of the results over different clients, as seen in this table.
Machine : 80x-BROADWELL-NUMA
Benchmark : kernbench (kernel compilation)
Varying parameter : number of jobs
Unit : seconds (lower is better)
5.2.0 vanilla (BASELINE) 5.2.0 intel_pstate 5.2.0 1C-turbo
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Amean 2 379.68 +- 0.06% ( ) 330.20 +- 0.43% ( 13.03%) 285.93 +- 0.07% ( 24.69%)
Amean 4 200.15 +- 0.24% ( ) 175.89 +- 0.22% ( 12.12%) 153.78 +- 0.25% ( 23.17%)
Amean 8 106.20 +- 0.31% ( ) 95.54 +- 0.23% ( 10.03%) 86.74 +- 0.10% ( 18.32%)
Amean 16 56.96 +- 1.31% ( ) 53.25 +- 1.22% ( 6.50%) 48.34 +- 1.73% ( 15.13%)
Amean 32 34.80 +- 2.46% ( ) 33.81 +- 0.77% ( 2.83%) 30.28 +- 1.59% ( 12.99%)
Amean 64 26.11 +- 1.63% ( ) 25.04 +- 1.07% ( 4.10%) 22.41 +- 2.37% ( 14.16%)
Amean 128 24.80 +- 1.36% ( ) 23.57 +- 1.23% ( 4.93%) 21.44 +- 1.37% ( 13.55%)
Amean 160 24.85 +- 0.56% ( ) 23.85 +- 1.17% ( 4.06%) 21.25 +- 1.12% ( 14.49%)
5.2.0 3C-turbo 5.2.0 4C-turbo 5.2.0 8C-turbo
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Amean 2 284.08 +- 0.13% ( 25.18%) 283.96 +- 0.51% ( 25.21%) 285.05 +- 0.21% ( 24.92%)
Amean 4 153.18 +- 0.22% ( 23.47%) 154.70 +- 1.64% ( 22.71%) 153.64 +- 0.30% ( 23.24%)
Amean 8 87.06 +- 0.28% ( 18.02%) 86.77 +- 0.46% ( 18.29%) 86.78 +- 0.22% ( 18.28%)
Amean 16 48.03 +- 0.93% ( 15.68%) 47.75 +- 1.99% ( 16.17%) 47.52 +- 1.61% ( 16.57%)
Amean 32 30.23 +- 1.20% ( 13.14%) 30.08 +- 1.67% ( 13.57%) 30.07 +- 1.67% ( 13.60%)
Amean 64 22.59 +- 2.02% ( 13.50%) 22.63 +- 0.81% ( 13.32%) 22.42 +- 0.76% ( 14.12%)
Amean 128 21.37 +- 0.67% ( 13.82%) 21.31 +- 1.15% ( 14.07%) 21.17 +- 1.93% ( 14.63%)
Amean 160 21.68 +- 0.57% ( 12.76%) 21.18 +- 1.74% ( 14.77%) 21.22 +- 1.00% ( 14.61%)
The patch outperform active intel_pstate (and baseline) by a considerable
margin; the summary table from the previous section says 4C turbo and active
intel_pstate are 0.83 and 0.93 against baseline respectively, so 4C turbo is
0.83/0.93=0.89 against intel_pstate (~10% better on average). There is no
noticeable difference with regard to the value of freq_max.
Machine : 8x-SKYLAKE-UMA
Benchmark : gitsource (time to run the git unit test suite)
Varying parameter : none
Unit : seconds (lower is better)
5.2.0 vanilla 5.2.0 intel_pstate/hwp 5.2.0 1C-turbo
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Amean 858.85 +- 1.16% ( ) 791.94 +- 0.21% ( 7.79%) 474.95 ( 44.70%)
5.2.0 3C-turbo 5.2.0 4C-turbo
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Amean 475.26 +- 0.20% ( 44.66%) 474.34 +- 0.13% ( 44.77%)
In this test, which is of interest as representing shell-intensive
(i.e. fork-intensive) serialized workloads, invariant schedutil outperforms
intel_pstate/powersave by a whopping 40% margin.
5.3.4 POWER CONSUMPTION, PERFORMANCE-PER-WATT
---------------------------------------------
The following table shows average power consumption in watt for each
benchmark. Data comes from turbostat (package average), which in turn is read
from the RAPL interface on CPUs. We know the patch affects CPU frequencies so
it's reasonable to ignore other power consumers (such as memory or I/O). Also,
we don't have a power meter available in the lab so RAPL is the best we have.
turbostat sampled average power every 10 seconds for the entire duration of
each benchmark. We took all those values and averaged them (i.e. with don't
have detail on a per-parameter granularity, only on whole benchmarks).
80x-BROADWELL-NUMA (power consumption, watts)
+--------+
BASELINE I_PSTATE 1C 3C | 4C | 8C
pgbench-ro 130.01 142.77 131.11 132.45 | 134.65 | 136.84
pgbench-rw 68.30 60.83 71.45 71.70 | 71.65 | 72.54
dbench4 90.25 59.06 101.43 99.89 | 101.10 | 102.94
netperf-udp 65.70 69.81 66.02 68.03 | 68.27 | 68.95
netperf-tcp 88.08 87.96 88.97 88.89 | 88.85 | 88.20
tbench4 142.32 176.73 153.02 163.91 | 165.58 | 176.07
kernbench 92.94 101.95 114.91 115.47 | 115.52 | 115.10
gitsource 40.92 41.87 75.14 75.20 | 75.40 | 75.70
+--------+
8x-SKYLAKE-UMA (power consumption, watts)
+--------+
BASELINE I_PSTATE/HWP 1C 3C | 4C |
pgbench-ro 46.49 46.68 46.56 46.59 | 46.52 |
pgbench-rw 29.34 31.38 30.98 31.00 | 31.00 |
dbench4 27.28 27.37 27.49 27.41 | 27.38 |
netperf-udp 22.33 22.41 22.36 22.35 | 22.36 |
netperf-tcp 27.29 27.29 27.30 27.31 | 27.33 |
tbench4 41.13 45.61 43.10 43.33 | 43.56 |
kernbench 42.56 42.63 43.01 43.01 | 43.01 |
gitsource 13.32 13.69 17.33 17.30 | 17.35 |
+--------+
48x-HASWELL-NUMA (power consumption, watts)
+--------+
BASELINE I_PSTATE 1C 3C | 4C | 12C
pgbench-ro 128.84 136.04 129.87 132.43 | 132.30 | 134.86
pgbench-rw 37.68 37.92 37.17 37.74 | 37.73 | 37.31
dbench4 28.56 28.73 28.60 28.73 | 28.70 | 28.79
netperf-udp 56.70 60.44 56.79 57.42 | 57.54 | 57.52
netperf-tcp 75.49 75.27 75.87 76.02 | 76.01 | 75.95
tbench4 115.44 139.51 119.53 123.07 | 123.97 | 130.22
kernbench 83.23 91.55 95.58 95.69 | 95.72 | 96.04
gitsource 36.79 36.99 39.99 40.34 | 40.35 | 40.23
+--------+
A lower power consumption isn't necessarily better, it depends on what is done
with that energy. Here are tables with the ratio of performance-per-watt on
each machine and benchmark. Higher is always better; a tilde (~) means a
neutral ratio (i.e. 1.00).
80x-BROADWELL-NUMA (performance-per-watt ratios; higher is better)
+------+
I_PSTATE 1C 3C | 4C | 8C
pgbench-ro 1.04 1.06 0.94 | 1.07 | 1.08
pgbench-rw 1.10 0.97 0.96 | 0.96 | 0.97
dbench4 1.24 0.94 0.95 | 0.94 | 0.92
netperf-udp ~ 1.02 1.02 | ~ | 1.02
netperf-tcp ~ 1.02 ~ | ~ | 1.02
tbench4 1.26 1.10 1.06 | 1.12 | 1.26
kernbench 0.98 0.97 0.97 | 0.97 | 0.98
gitsource ~ 1.11 1.11 | 1.11 | 1.13
+------+
8x-SKYLAKE-UMA (performance-per-watt ratios; higher is better)
+------+
I_PSTATE/HWP 1C 3C | 4C |
pgbench-ro ~ ~ ~ | ~ |
pgbench-rw 0.95 0.97 0.96 | 0.96 |
dbench4 ~ ~ ~ | ~ |
netperf-udp ~ ~ ~ | ~ |
netperf-tcp ~ ~ ~ | ~ |
tbench4 1.17 1.09 1.08 | 1.10 |
kernbench ~ ~ ~ | ~ |
gitsource 1.06 1.40 1.40 | 1.40 |
+------+
48x-HASWELL-NUMA (performance-per-watt ratios; higher is better)
+------+
I_PSTATE 1C 3C | 4C | 12C
pgbench-ro 1.09 ~ 1.09 | 1.03 | 1.11
pgbench-rw ~ 0.86 ~ | ~ | 0.86
dbench4 ~ 1.02 1.02 | 1.02 | ~
netperf-udp ~ 0.97 1.03 | 1.02 | ~
netperf-tcp 0.96 ~ ~ | ~ | ~
tbench4 1.24 ~ 1.06 | 1.05 | 1.11
kernbench 0.97 0.97 0.98 | 0.97 | 0.96
gitsource 1.03 1.33 1.32 | 1.32 | 1.33
+------+
These results are overall pleasing: in plenty of cases we observe
performance-per-watt improvements. The few regressions (read/write pgbench and
dbench on the Broadwell machine) are of small magnitude. kernbench loses a few
percentage points (it has a 10-15% performance improvement, but apparently the
increase in power consumption is larger than that). tbench4 and gitsource, which
benefit the most from the patch, keep a positive score in this table which is
a welcome surprise; that suggests that in those particular workloads the
non-invariant schedutil (and active intel_pstate, too) makes some rather
suboptimal frequency selections.
+-------------------------------------------------------------------------+
| 6. MICROARCH'ES ADDRESSED HERE
+-------------------------------------------------------------------------+
The patch addresses Xeon Core processors that use MSR_PLATFORM_INFO and
MSR_TURBO_RATIO_LIMIT to advertise their base frequency and turbo frequencies
respectively. This excludes the recent Xeon Scalable Performance processors
line (Xeon Gold, Platinum etc) whose MSRs have to be parsed differently.
Subsequent patches will address:
* Xeon Scalable Performance processors and Atom Goldmont/Goldmont Plus
* Xeon Phi (Knights Landing, Knights Mill)
* Atom Silvermont
+-------------------------------------------------------------------------+
| 7. REFERENCES
+-------------------------------------------------------------------------+
Tests have been run with the help of the MMTests performance testing
framework, see github.com/gormanm/mmtests. The configuration file names for
the benchmark used are:
db-pgbench-timed-ro-small-xfs
db-pgbench-timed-rw-small-xfs
io-dbench4-async-xfs
network-netperf-unbound
network-tbench
scheduler-unbound
workload-kerndevel-xfs
workload-shellscripts-xfs
hpc-nas-c-class-mpi-full-xfs
hpc-nas-c-class-omp-full
All those benchmarks are generally available on the web:
pgbench: https://www.postgresql.org/docs/10/pgbench.html
netperf: https://hewlettpackard.github.io/netperf/
dbench/tbench: https://dbench.samba.org/
gitsource: git unit test suite, github.com/git/git
NAS Parallel Benchmarks: https://www.nas.nasa.gov/publications/npb.html
hackbench: https://people.redhat.com/mingo/cfs-scheduler/tools/hackbench.c
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Giovanni Gherdovich <ggherdovich@suse.cz>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Doug Smythies <dsmythies@telus.net>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lkml.kernel.org/r/20200122151617.531-2-ggherdovich@suse.cz
|
|
|
Linus Torvalds
|
c5f12fdb8b |
Merge branch 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 apic updates from Thomas Gleixner: - Cleanup the apic IPI implementation by removing duplicated code and consolidating the functions into the APIC core. - Implement a safe variant of the IPI broadcast mode. Contrary to earlier attempts this uses the core tracking of which CPUs have been brought online at least once so that a broadcast does not end up in some dead end in BIOS/SMM code when the CPU is still waiting for init. Once all CPUs have been brought up once, IPI broadcasting is enabled. Before that regular one by one IPIs are issued. - Drop the paravirt CR8 related functions as they have no user anymore - Initialize the APIC TPR to block interrupt 16-31 as they are reserved for CPU exceptions and should never be raised by any well behaving device. - Emit a warning when vector space exhaustion breaks the admin set affinity of an interrupt. - Make sure to use the NMI fallback when shutdown via reboot vector IPI fails. The original code had conditions which prevent the code path to be reached. - Annotate various APIC config variables as RO after init. [ The ipi broadcase change came in earlier through the cpu hotplug branch, but I left the explanation in the commit message since it was shared between the two different branches - Linus ] * 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (28 commits) x86/apic/vector: Warn when vector space exhaustion breaks affinity x86/apic: Annotate global config variables as "read-only after init" x86/apic/x2apic: Implement IPI shorthands support x86/apic/flat64: Remove the IPI shorthand decision logic x86/apic: Share common IPI helpers x86/apic: Remove the shorthand decision logic x86/smp: Enhance native_send_call_func_ipi() x86/smp: Move smp_function_call implementations into IPI code x86/apic: Provide and use helper for send_IPI_allbutself() x86/apic: Add static key to Control IPI shorthands x86/apic: Move no_ipi_broadcast() out of 32bit x86/apic: Add NMI_VECTOR wait to IPI shorthand x86/apic: Remove dest argument from __default_send_IPI_shortcut() x86/hotplug: Silence APIC and NMI when CPU is dead x86/cpu: Move arch_smt_update() to a neutral place x86/apic/uv: Make x2apic_extra_bits static x86/apic: Consolidate the apic local headers x86/apic: Move apic_flat_64 header into apic directory x86/apic: Move ipi header into apic directory x86/apic: Cleanup the include maze ... |
|
|
Thomas Gleixner
|
60dcaad573 |
x86/hotplug: Silence APIC and NMI when CPU is dead
In order to support IPI/NMI broadcasting via the shorthand mechanism side effects of shorthands need to be mitigated: Shorthand IPIs and NMIs hit all CPUs including unplugged CPUs Neither of those can be handled on unplugged CPUs for obvious reasons. It would be trivial to just fully disable the APIC via the enable bit in MSR_APICBASE. But that's not possible because clearing that bit on systems based on the 3 wire APIC bus would require a hardware reset to bring it back as the APIC would lose track of bus arbitration. On systems with FSB delivery APICBASE could be disabled, but it has to be guaranteed that no interrupt is sent to the APIC while in that state and it's not clear from the SDM whether it still responds to INIT/SIPI messages. Therefore stay on the safe side and switch the APIC into soft disabled mode so it won't deliver any regular vector to the CPU. NMIs are still propagated to the 'dead' CPUs. To mitigate that add a check for the CPU being offline on early nmi entry and if so bail. Note, this cannot use the stop/restart_nmi() magic which is used in the alternatives code. A dead CPU cannot invoke nmi_enter() or anything else due to RCU and other reasons. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1907241723290.1791@nanos.tec.linutronix.de |
|
|
Pingfan Liu
|
6973210242 |
x86/realmode: Remove trampoline_status
There is no reader of trampoline_status, it's only written.
It turns out that after commit
|
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Zhenzhong Duan
|
090d54bcbc |
Revert "x86/paravirt: Set up the virt_spin_lock_key after static keys get initialized"
This reverts commit |
|
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Thomas Gleixner
|
7652ac9201 |
x86/asm: Move native_write_cr0/4() out of line
The pinning of sensitive CR0 and CR4 bits caused a boot crash when loading the kvm_intel module on a kernel compiled with CONFIG_PARAVIRT=n. The reason is that the static key which controls the pinning is marked RO after init. The kvm_intel module contains a CR4 write which requires to update the static key entry list. That obviously does not work when the key is in a RO section. With CONFIG_PARAVIRT enabled this does not happen because the CR4 write uses the paravirt indirection and the actual write function is built in. As the key is intended to be immutable after init, move native_write_cr0/4() out of line. While at it consolidate the update of the cr4 shadow variable and store the value right away when the pinning is initialized on a booting CPU. No point in reading it back 20 instructions later. This allows to confine the static key and the pinning variable to cpu/common and allows to mark them static. Fixes: |
|
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Linus Torvalds
|
222a21d295 |
Merge branch 'x86-topology-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 topology updates from Ingo Molnar: "Implement multi-die topology support on Intel CPUs and expose the die topology to user-space tooling, by Len Brown, Kan Liang and Zhang Rui. These changes should have no effect on the kernel's existing understanding of topologies, i.e. there should be no behavioral impact on cache, NUMA, scheduler, perf and other topologies and overall system performance" * 'x86-topology-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf/x86/intel/rapl: Cosmetic rename internal variables in response to multi-die/pkg support perf/x86/intel/uncore: Cosmetic renames in response to multi-die/pkg support hwmon/coretemp: Cosmetic: Rename internal variables to zones from packages thermal/x86_pkg_temp_thermal: Cosmetic: Rename internal variables to zones from packages perf/x86/intel/cstate: Support multi-die/package perf/x86/intel/rapl: Support multi-die/package perf/x86/intel/uncore: Support multi-die/package topology: Create core_cpus and die_cpus sysfs attributes topology: Create package_cpus sysfs attribute hwmon/coretemp: Support multi-die/package powercap/intel_rapl: Update RAPL domain name and debug messages thermal/x86_pkg_temp_thermal: Support multi-die/package powercap/intel_rapl: Support multi-die/package powercap/intel_rapl: Simplify rapl_find_package() x86/topology: Define topology_logical_die_id() x86/topology: Define topology_die_id() cpu/topology: Export die_id x86/topology: Create topology_max_die_per_package() x86/topology: Add CPUID.1F multi-die/package support |
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Kees Cook
|
873d50d58f |
x86/asm: Pin sensitive CR4 bits
Several recent exploits have used direct calls to the native_write_cr4() function to disable SMEP and SMAP before then continuing their exploits using userspace memory access. Direct calls of this form can be mitigate by pinning bits of CR4 so that they cannot be changed through a common function. This is not intended to be a general ROP protection (which would require CFI to defend against properly), but rather a way to avoid trivial direct function calling (or CFI bypasses via a matching function prototype) as seen in: https://googleprojectzero.blogspot.com/2017/05/exploiting-linux-kernel-via-packet.html (https://github.com/xairy/kernel-exploits/tree/master/CVE-2017-7308) The goals of this change: - Pin specific bits (SMEP, SMAP, and UMIP) when writing CR4. - Avoid setting the bits too early (they must become pinned only after CPU feature detection and selection has finished). - Pinning mask needs to be read-only during normal runtime. - Pinning needs to be checked after write to validate the cr4 state Using __ro_after_init on the mask is done so it can't be first disabled with a malicious write. Since these bits are global state (once established by the boot CPU and kernel boot parameters), they are safe to write to secondary CPUs before those CPUs have finished feature detection. As such, the bits are set at the first cr4 write, so that cr4 write bugs can be detected (instead of silently papered over). This uses a few bytes less storage of a location we don't have: read-only per-CPU data. A check is performed after the register write because an attack could just skip directly to the register write. Such a direct jump is possible because of how this function may be built by the compiler (especially due to the removal of frame pointers) where it doesn't add a stack frame (function exit may only be a retq without pops) which is sufficient for trivial exploitation like in the timer overwrites mentioned above). The asm argument constraints gain the "+" modifier to convince the compiler that it shouldn't make ordering assumptions about the arguments or memory, and treat them as changed. Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@intel.com> Cc: kernel-hardening@lists.openwall.com Link: https://lkml.kernel.org/r/20190618045503.39105-3-keescook@chromium.org |
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Thomas Gleixner
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9ff554e9be |
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 82
Based on 1 normalized pattern(s): this code is released under the gnu general public license version 2 or later extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Richard Fontana <rfontana@redhat.com> Reviewed-by: Armijn Hemel <armijn@tjaldur.nl> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190520075211.232210963@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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Len Brown
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2e4c54dac7 |
topology: Create core_cpus and die_cpus sysfs attributes
Create CPU topology sysfs attributes: "core_cpus" and "core_cpus_list" These attributes represent all of the logical CPUs that share the same core. These attriutes is synonymous with the existing "thread_siblings" and "thread_siblings_list" attribute, which will be deprecated. Create CPU topology sysfs attributes: "die_cpus" and "die_cpus_list". These attributes represent all of the logical CPUs that share the same die. Suggested-by: Brice Goglin <Brice.Goglin@inria.fr> Signed-off-by: Len Brown <len.brown@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/071c23a298cd27ede6ed0b6460cae190d193364f.1557769318.git.len.brown@intel.com |
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Len Brown
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212bf4fdb7 |
x86/topology: Define topology_logical_die_id()
Define topology_logical_die_id() ala existing topology_logical_package_id() Signed-off-by: Len Brown <len.brown@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Zhang Rui <rui.zhang@intel.com> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/2f3526e25ae14fbeff26fb26e877d159df8946d9.1557769318.git.len.brown@intel.com |
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Len Brown
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7745f03eb3 |
x86/topology: Add CPUID.1F multi-die/package support
Some new systems have multiple software-visible die within each package. Update Linux parsing of the Intel CPUID "Extended Topology Leaf" to handle either CPUID.B, or the new CPUID.1F. Add cpuinfo_x86.die_id and cpuinfo_x86.max_dies to store the result. die_id will be non-zero only for multi-die/package systems. Signed-off-by: Len Brown <len.brown@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: linux-doc@vger.kernel.org Link: https://lkml.kernel.org/r/7b23d2d26d717b8e14ba137c94b70943f1ae4b5c.1557769318.git.len.brown@intel.com |
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Linus Torvalds
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948a64995a |
Merge branch 'x86-topology-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 topology updates from Ingo Molnar: "Two main changes: preparatory changes for Intel multi-die topology support, plus a syslog message tweak" * 'x86-topology-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/topology: Make DEBUG_HOTPLUG_CPU0 pr_info() more descriptive x86/smpboot: Rename match_die() to match_pkg() topology: Simplify cputopology.txt formatting and wording x86/topology: Fix documentation typo |
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Len Brown
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169d086996 |
x86/smpboot: Rename match_die() to match_pkg()
Syntax only, no functional or semantic change. This routine matches packages, not die, so name it thus. Signed-off-by: Len Brown <len.brown@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/7ca18c4ae7816a1f9eda37414725df676e63589d.1551160674.git.len.brown@intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Thomas Gleixner
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66c7ceb47f |
x86/irq/32: Handle irq stack allocation failure proper
irq_ctx_init() crashes hard on page allocation failures. While that's ok during early boot, it's just wrong in the CPU hotplug bringup code. Check the page allocation failure and return -ENOMEM and handle it at the call sites. On early boot the only way out is to BUG(), but on CPU hotplug there is no reason to crash, so just abort the operation. Rename the function to something more sensible while at it. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Alison Schofield <alison.schofield@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Nicolai Stange <nstange@suse.de> Cc: Pu Wen <puwen@hygon.cn> Cc: Sean Christopherson <sean.j.christopherson@intel.com> Cc: Shaokun Zhang <zhangshaokun@hisilicon.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Cc: x86-ml <x86@kernel.org> Cc: xen-devel@lists.xenproject.org Cc: Yazen Ghannam <yazen.ghannam@amd.com> Cc: Yi Wang <wang.yi59@zte.com.cn> Cc: Zhenzhong Duan <zhenzhong.duan@oracle.com> Link: https://lkml.kernel.org/r/20190414160146.089060584@linutronix.de |
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Linus Torvalds
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bcd49c3dd1 |
Merge branch 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 cleanups from Ingo Molnar: "Various cleanups and simplifications, none of them really stands out, they are all over the place" * 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/uaccess: Remove unused __addr_ok() macro x86/smpboot: Remove unused phys_id variable x86/mm/dump_pagetables: Remove the unused prev_pud variable x86/fpu: Move init_xstate_size() to __init section x86/cpu_entry_area: Move percpu_setup_debug_store() to __init section x86/mtrr: Remove unused variable x86/boot/compressed/64: Explain paging_prepare()'s return value x86/resctrl: Remove duplicate MSR_MISC_FEATURE_CONTROL definition x86/asm/suspend: Drop ENTRY from local data x86/hw_breakpoints, kprobes: Remove kprobes ifdeffery x86/boot: Save several bytes in decompressor x86/trap: Remove useless declaration x86/mm/tlb: Remove unused cpu variable x86/events: Mark expected switch-case fall-throughs x86/asm-prototypes: Remove duplicate include <asm/page.h> x86/kernel: Mark expected switch-case fall-throughs x86/insn-eval: Mark expected switch-case fall-through x86/platform/UV: Replace kmalloc() and memset() with k[cz]alloc() calls x86/e820: Replace kmalloc() + memcpy() with kmemdup() |
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Anshuman Khandual
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98fa15f34c |
mm: replace all open encodings for NUMA_NO_NODE
Patch series "Replace all open encodings for NUMA_NO_NODE", v3. All these places for replacement were found by running the following grep patterns on the entire kernel code. Please let me know if this might have missed some instances. This might also have replaced some false positives. I will appreciate suggestions, inputs and review. 1. git grep "nid == -1" 2. git grep "node == -1" 3. git grep "nid = -1" 4. git grep "node = -1" This patch (of 2): At present there are multiple places where invalid node number is encoded as -1. Even though implicitly understood it is always better to have macros in there. Replace these open encodings for an invalid node number with the global macro NUMA_NO_NODE. This helps remove NUMA related assumptions like 'invalid node' from various places redirecting them to a common definition. Link: http://lkml.kernel.org/r/1545127933-10711-2-git-send-email-anshuman.khandual@arm.com Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com> [ixgbe] Acked-by: Jens Axboe <axboe@kernel.dk> [mtip32xx] Acked-by: Vinod Koul <vkoul@kernel.org> [dmaengine.c] Acked-by: Michael Ellerman <mpe@ellerman.id.au> [powerpc] Acked-by: Doug Ledford <dledford@redhat.com> [drivers/infiniband] Cc: Joseph Qi <jiangqi903@gmail.com> Cc: Hans Verkuil <hverkuil@xs4all.nl> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Shaokun Zhang
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f91fecc09e |
x86/smpboot: Remove unused phys_id variable
The 'phys_id' local variable became unused after commit
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Hui Wang
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aa02ef099c |
x86/topology: Use total_cpus for max logical packages calculation
nr_cpu_ids can be limited on the command line via nr_cpus=. This can break the logical package management because it results in a smaller number of packages while in kdump kernel. Check below case: There is a two sockets system, each socket has 8 cores, which has 16 logical cpus while HT was turn on. 0 1 2 3 4 5 6 7 | 16 17 18 19 20 21 22 23 cores on socket 0 threads on socket 0 8 9 10 11 12 13 14 15 | 24 25 26 27 28 29 30 31 cores on socket 1 threads on socket 1 While starting the kdump kernel with command line option nr_cpus=16 panic was triggered on one of the cpus 24-31 eg. 26, then online cpu will be 1-15, 26(cpu 0 was disabled in kdump), ncpus will be 16 and __max_logical_packages will be 1, but actually two packages were booted on. This issue can reproduced by set kdump option nr_cpus=<real physical core numbers>, and then trigger panic on last socket's thread, for example: taskset -c 26 echo c > /proc/sysrq-trigger Use total_cpus which will not be limited by nr_cpus command line to calculate the value of __max_logical_packages. Signed-off-by: Hui Wang <john.wanghui@huawei.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: <guijianfeng@huawei.com> Cc: <wencongyang2@huawei.com> Cc: <douliyang1@huawei.com> Cc: <qiaonuohan@huawei.com> Link: https://lkml.kernel.org/r/20181107023643.22174-1-john.wanghui@huawei.com |
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Mike Rapoport
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57c8a661d9 |
mm: remove include/linux/bootmem.h
Move remaining definitions and declarations from include/linux/bootmem.h into include/linux/memblock.h and remove the redundant header. The includes were replaced with the semantic patch below and then semi-automated removal of duplicated '#include <linux/memblock.h> @@ @@ - #include <linux/bootmem.h> + #include <linux/memblock.h> [sfr@canb.auug.org.au: dma-direct: fix up for the removal of linux/bootmem.h] Link: http://lkml.kernel.org/r/20181002185342.133d1680@canb.auug.org.au [sfr@canb.auug.org.au: powerpc: fix up for removal of linux/bootmem.h] Link: http://lkml.kernel.org/r/20181005161406.73ef8727@canb.auug.org.au [sfr@canb.auug.org.au: x86/kaslr, ACPI/NUMA: fix for linux/bootmem.h removal] Link: http://lkml.kernel.org/r/20181008190341.5e396491@canb.auug.org.au Link: http://lkml.kernel.org/r/1536927045-23536-30-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Zankel <chris@zankel.net> Cc: "David S. Miller" <davem@davemloft.net> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greentime Hu <green.hu@gmail.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Guan Xuetao <gxt@pku.edu.cn> Cc: Ingo Molnar <mingo@redhat.com> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Jonas Bonn <jonas@southpole.se> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Ley Foon Tan <lftan@altera.com> Cc: Mark Salter <msalter@redhat.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Matt Turner <mattst88@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Simek <monstr@monstr.eu> Cc: Palmer Dabbelt <palmer@sifive.com> Cc: Paul Burton <paul.burton@mips.com> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: Richard Weinberger <richard@nod.at> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Serge Semin <fancer.lancer@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Pu Wen
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0b13bec787 |
x86/smpboot: Do not use BSP INIT delay and MWAIT to idle on Dhyana
The Hygon Dhyana CPU uses no delay in smp_quirk_init_udelay(), and does HLT on idle just like AMD does. Signed-off-by: Pu Wen <puwen@hygon.cn> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: bp@alien8.de Cc: tglx@linutronix.de Cc: mingo@redhat.com Cc: hpa@zytor.com Cc: x86@kernel.org Cc: thomas.lendacky@amd.com Link: https://lkml.kernel.org/r/87000fa82e273f5967c908448414228faf61e077.1537533369.git.puwen@hygon.cn |
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Thomas Gleixner
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f2701b77bb |
Merge 4.18-rc7 into master to pick up the KVM dependcy
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
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Nicolai Stange
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447ae31667 |
x86: Don't include linux/irq.h from asm/hardirq.h
The next patch in this series will have to make the definition of
irq_cpustat_t available to entering_irq().
Inclusion of asm/hardirq.h into asm/apic.h would cause circular header
dependencies like
asm/smp.h
asm/apic.h
asm/hardirq.h
linux/irq.h
linux/topology.h
linux/smp.h
asm/smp.h
or
linux/gfp.h
linux/mmzone.h
asm/mmzone.h
asm/mmzone_64.h
asm/smp.h
asm/apic.h
asm/hardirq.h
linux/irq.h
linux/irqdesc.h
linux/kobject.h
linux/sysfs.h
linux/kernfs.h
linux/idr.h
linux/gfp.h
and others.
This causes compilation errors because of the header guards becoming
effective in the second inclusion: symbols/macros that had been defined
before wouldn't be available to intermediate headers in the #include chain
anymore.
A possible workaround would be to move the definition of irq_cpustat_t
into its own header and include that from both, asm/hardirq.h and
asm/apic.h.
However, this wouldn't solve the real problem, namely asm/harirq.h
unnecessarily pulling in all the linux/irq.h cruft: nothing in
asm/hardirq.h itself requires it. Also, note that there are some other
archs, like e.g. arm64, which don't have that #include in their
asm/hardirq.h.
Remove the linux/irq.h #include from x86' asm/hardirq.h.
Fix resulting compilation errors by adding appropriate #includes to *.c
files as needed.
Note that some of these *.c files could be cleaned up a bit wrt. to their
set of #includes, but that should better be done from separate patches, if
at all.
Signed-off-by: Nicolai Stange <nstange@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Zhenzhong Duan
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4fb5f58e8d |
x86/mm/32: Initialize the CR4 shadow before __flush_tlb_all()
On 32-bit kernels, __flush_tlb_all() may have read the CR4 shadow before the initialization of CR4 shadow in cpu_init(). Fix it by adding an explicit cr4_init_shadow() call into start_secondary() which is the first function called on non-boot SMP CPUs - ahead of the __flush_tlb_all() call. ( This is somewhat of a layering violation, but start_secondary() does CR4 bootstrap in the PCID case anyway. ) Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Link: http://lkml.kernel.org/r/b07b6ae9-4b57-4b40-b9bc-50c2c67f1d91@default Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Thomas Gleixner
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f048c399e0 |
x86/topology: Provide topology_smt_supported()
Provide information whether SMT is supoorted by the CPUs. Preparatory patch for SMT control mechanism. Suggested-by: Dave Hansen <dave.hansen@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@kernel.org> |