linux/arch/powerpc/kvm
Michal Hocko dcda9b0471 mm, tree wide: replace __GFP_REPEAT by __GFP_RETRY_MAYFAIL with more useful semantic
__GFP_REPEAT was designed to allow retry-but-eventually-fail semantic to
the page allocator.  This has been true but only for allocations
requests larger than PAGE_ALLOC_COSTLY_ORDER.  It has been always
ignored for smaller sizes.  This is a bit unfortunate because there is
no way to express the same semantic for those requests and they are
considered too important to fail so they might end up looping in the
page allocator for ever, similarly to GFP_NOFAIL requests.

Now that the whole tree has been cleaned up and accidental or misled
usage of __GFP_REPEAT flag has been removed for !costly requests we can
give the original flag a better name and more importantly a more useful
semantic.  Let's rename it to __GFP_RETRY_MAYFAIL which tells the user
that the allocator would try really hard but there is no promise of a
success.  This will work independent of the order and overrides the
default allocator behavior.  Page allocator users have several levels of
guarantee vs.  cost options (take GFP_KERNEL as an example)

 - GFP_KERNEL & ~__GFP_RECLAIM - optimistic allocation without _any_
   attempt to free memory at all. The most light weight mode which even
   doesn't kick the background reclaim. Should be used carefully because
   it might deplete the memory and the next user might hit the more
   aggressive reclaim

 - GFP_KERNEL & ~__GFP_DIRECT_RECLAIM (or GFP_NOWAIT)- optimistic
   allocation without any attempt to free memory from the current
   context but can wake kswapd to reclaim memory if the zone is below
   the low watermark. Can be used from either atomic contexts or when
   the request is a performance optimization and there is another
   fallback for a slow path.

 - (GFP_KERNEL|__GFP_HIGH) & ~__GFP_DIRECT_RECLAIM (aka GFP_ATOMIC) -
   non sleeping allocation with an expensive fallback so it can access
   some portion of memory reserves. Usually used from interrupt/bh
   context with an expensive slow path fallback.

 - GFP_KERNEL - both background and direct reclaim are allowed and the
   _default_ page allocator behavior is used. That means that !costly
   allocation requests are basically nofail but there is no guarantee of
   that behavior so failures have to be checked properly by callers
   (e.g. OOM killer victim is allowed to fail currently).

 - GFP_KERNEL | __GFP_NORETRY - overrides the default allocator behavior
   and all allocation requests fail early rather than cause disruptive
   reclaim (one round of reclaim in this implementation). The OOM killer
   is not invoked.

 - GFP_KERNEL | __GFP_RETRY_MAYFAIL - overrides the default allocator
   behavior and all allocation requests try really hard. The request
   will fail if the reclaim cannot make any progress. The OOM killer
   won't be triggered.

 - GFP_KERNEL | __GFP_NOFAIL - overrides the default allocator behavior
   and all allocation requests will loop endlessly until they succeed.
   This might be really dangerous especially for larger orders.

Existing users of __GFP_REPEAT are changed to __GFP_RETRY_MAYFAIL
because they already had their semantic.  No new users are added.
__alloc_pages_slowpath is changed to bail out for __GFP_RETRY_MAYFAIL if
there is no progress and we have already passed the OOM point.

This means that all the reclaim opportunities have been exhausted except
the most disruptive one (the OOM killer) and a user defined fallback
behavior is more sensible than keep retrying in the page allocator.

[akpm@linux-foundation.org: fix arch/sparc/kernel/mdesc.c]
[mhocko@suse.com: semantic fix]
  Link: http://lkml.kernel.org/r/20170626123847.GM11534@dhcp22.suse.cz
[mhocko@kernel.org: address other thing spotted by Vlastimil]
  Link: http://lkml.kernel.org/r/20170626124233.GN11534@dhcp22.suse.cz
Link: http://lkml.kernel.org/r/20170623085345.11304-3-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Alex Belits <alex.belits@cavium.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: David Daney <david.daney@cavium.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: NeilBrown <neilb@suse.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-12 16:26:03 -07:00
..
Kconfig KVM: PPC: Book3S PR: Don't include SPAPR TCE code on non-pseries platforms 2017-05-12 15:32:30 +10:00
Makefile KVM: PPC: Book3S PR: Don't include SPAPR TCE code on non-pseries platforms 2017-05-12 15:32:30 +10:00
book3s.c * ARM: HYP mode stub supports kexec/kdump on 32-bit; improved PMU 2017-05-08 12:37:56 -07:00
book3s.h kvm: Fix page ageing bugs 2014-09-24 14:07:58 +02:00
book3s_32_mmu.c KVM: PPC: Book3S PR: Ratelimit copy data failure error messages 2017-02-17 14:03:35 +11:00
book3s_32_mmu_host.c powerpc/mm: Move hash related mmu-*.h headers to book3s/ 2016-03-03 21:19:21 +11:00
book3s_32_sr.S KVM: PPC: book3s_pr: Simplify transitions between virtual and real mode 2011-09-25 19:52:29 +03:00
book3s_64_mmu.c KVM: PPC: Book3S PR: Preserve storage control bits 2017-04-20 11:38:14 +10:00
book3s_64_mmu_host.c * ARM: HYP mode stub supports kexec/kdump on 32-bit; improved PMU 2017-05-08 12:37:56 -07:00
book3s_64_mmu_hv.c mm, tree wide: replace __GFP_REPEAT by __GFP_RETRY_MAYFAIL with more useful semantic 2017-07-12 16:26:03 -07:00
book3s_64_mmu_radix.c KVM: PPC: Book3S HV: Fix software walk of guest process page tables 2017-03-01 11:53:45 +11:00
book3s_64_slb.S KVM: PPC: Book3S PR: Rework SLB switching code 2014-05-30 14:26:30 +02:00
book3s_64_vio.c KVM: PPC: VFIO: Add in-kernel acceleration for VFIO 2017-04-20 11:39:26 +10:00
book3s_64_vio_hv.c KVM: PPC: Book3S HV: Add radix checks in real-mode hypercall handlers 2017-05-12 15:08:09 +10:00
book3s_emulate.c KVM: PPC: Book3S PR: Do not fail emulation with mtspr/mfspr for unknown SPRs 2017-04-20 11:39:32 +10:00
book3s_exports.c KVM: PPC: Make shared struct aka magic page guest endian 2014-05-30 14:26:21 +02:00
book3s_hv.c PPC: 2017-07-06 18:38:31 -07:00
book3s_hv_builtin.c KVM: PPC: Book3S HV: Simplify dynamic micro-threading code 2017-07-01 18:59:01 +10:00
book3s_hv_hmi.c powerpc: move hmi.c to arch/powerpc/kvm/ 2016-09-09 16:18:07 +10:00
book3s_hv_interrupts.S KVM: PPC: Book3S HV: Close race with testing for signals on guest entry 2017-07-01 18:59:38 +10:00
book3s_hv_ras.c KVM: PPC: Book3S HV: Exit guest upon MCE when FWNMI capability is enabled 2017-06-22 11:24:57 +10:00
book3s_hv_rm_mmu.c powerpc/mm: Trace tlbie(l) instructions 2017-06-23 21:14:49 +10:00
book3s_hv_rm_xics.c Merge branch 'kvm-ppc-next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc into HEAD 2017-05-09 11:50:01 +02:00
book3s_hv_rm_xive.c KVM: PPC: Book3S HV: Native usage of the XIVE interrupt controller 2017-04-27 21:37:29 +10:00
book3s_hv_rmhandlers.S powerpc updates for 4.13 2017-07-07 13:55:45 -07:00
book3s_interrupts.S powerpc: Define and use PPC64_ELF_ABI_v2/v1 2016-06-14 13:58:27 +10:00
book3s_mmu_hpte.c sched/headers: Prepare to use <linux/rcuupdate.h> instead of <linux/rculist.h> in <linux/sched.h> 2017-03-02 08:42:38 +01:00
book3s_paired_singles.c powerpc: Create disable_kernel_{fp,altivec,vsx,spe}() 2015-12-01 13:52:25 +11:00
book3s_pr.c KVM: add kvm_{test,clear}_request to replace {test,clear}_bit 2017-04-27 14:12:22 +02:00
book3s_pr_papr.c KVM: PPC: Book3S PR: Don't include SPAPR TCE code on non-pseries platforms 2017-05-12 15:32:30 +10:00
book3s_rmhandlers.S powerpc: Define and use PPC64_ELF_ABI_v2/v1 2016-06-14 13:58:27 +10:00
book3s_rtas.c KVM: PPC: Book3S HV: Native usage of the XIVE interrupt controller 2017-04-27 21:37:29 +10:00
book3s_segment.S KVM: PPC: Book3S: 64-bit CONFIG_RELOCATABLE support for interrupts 2017-01-31 19:07:39 +11:00
book3s_xics.c Merge branch 'kvm-ppc-next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc into HEAD 2017-05-09 11:50:01 +02:00
book3s_xics.h KVM: PPC: Book3S HV: Native usage of the XIVE interrupt controller 2017-04-27 21:37:29 +10:00
book3s_xive.c KVM: PPC: Book3S: Fix typo in XICS-on-XIVE state saving code 2017-07-03 10:40:22 +02:00
book3s_xive.h KVM: PPC: Book3S HV: Native usage of the XIVE interrupt controller 2017-04-27 21:37:29 +10:00
book3s_xive_template.c powerpc/xive: Fix offset for store EOI MMIOs 2017-06-15 23:29:39 +10:00
booke.c KVM: add kvm_request_pending 2017-06-04 16:53:00 +02:00
booke.h KVM: PPC: Book3e: Add AltiVec support 2014-09-22 10:11:32 +02:00
booke_emulate.c KVM: PPC: BOOKE: Emulate debug registers and exception 2014-09-22 10:11:33 +02:00
booke_interrupts.S KVM: PPC: Remove 440 support 2014-07-28 15:23:15 +02:00
bookehv_interrupts.S powerpc/kvm: common sw breakpoint instr across ppc 2014-09-22 10:11:36 +02:00
e500.c KVM: PPC: e500: fix handling local_sid_lookup result 2015-10-15 15:58:16 +11:00
e500.h kvm: rename pfn_t to kvm_pfn_t 2016-01-15 17:56:32 -08:00
e500_emulate.c KVM: PPC: e500: Emulate TMCFG0 TMRN register 2015-10-15 15:58:16 +11:00
e500_mmu.c KVM: PPC: e500: Rename jump labels in kvmppc_e500_tlb_init() 2016-09-13 14:32:47 +10:00
e500_mmu_host.c KVM: PPC: e500: Use kcalloc() in e500_mmu_host_init() 2017-04-20 11:37:55 +10:00
e500_mmu_host.h KVM: PPC: E500: Make clear_tlb_refs and clear_tlb1_bitmap static 2013-01-24 19:23:33 +01:00
e500mc.c powerpc: Fix misspellings in comments. 2016-03-01 19:27:20 +11:00
emulate.c KVM: PPC: Book3S HV: Enable guests to use large decrementer mode on POWER9 2017-06-19 14:02:04 +10:00
emulate_loadstore.c KVM: PPC: Add MMIO emulation for remaining floating-point instructions 2017-04-20 11:37:44 +10:00
fpu.S
irq.h KVM: PPC: Book3S HV: Native usage of the XIVE interrupt controller 2017-04-27 21:37:29 +10:00
mpic.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
powerpc.c Merge branch 'kvm-ppc-next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc into HEAD 2017-07-03 10:41:59 +02:00
timing.c KVM: PPC: Remove DCR handling 2014-07-28 19:29:15 +02:00
timing.h KVM: PPC: Remove DCR handling 2014-07-28 19:29:15 +02:00
trace.h kvm: powerpc: booke: Move booke related tracepoints to separate header 2013-10-17 15:37:16 +02:00
trace_book3s.h KVM: PPC: Book3S HV: Tracepoints for KVM HV guest interactions 2014-12-17 13:29:27 +01:00
trace_booke.h KVM: PPC: BookE: Improve irq inject tracepoint 2014-12-15 13:27:23 +01:00
trace_hv.h KVM: PPC: Book3S HV: Comment style and print format fixups 2016-11-28 11:48:47 +11:00
trace_pr.h kvm: rename pfn_t to kvm_pfn_t 2016-01-15 17:56:32 -08:00