linux/Documentation
David Howells 108b42b4b9 [PATCH] Document Linux's memory barriers [try #7]
The attached patch documents the Linux kernel's memory barriers.

I've updated it from the comments I've been given.

The per-arch notes sections are gone because it's clear that there are so many
exceptions, that it's not worth having them.

I've added a list of references to other documents.

I've tried to get rid of the concept of memory accesses appearing on the bus;
what matters is apparent behaviour with respect to other observers in the
system.

Interrupts barrier effects are now considered to be non-existent. They may be
there, but you may not rely on them.

I've added a couple of definition sections at the top of the document: one to
specify the minimum execution model that may be assumed, the other to specify
what this document refers to by the term "memory".

I've made greater mention of the use of mmiowb().

I've adjusted the way in which caches are described, and described the fun
that can be had with cache coherence maintenance being unordered and data
dependency not being necessarily implicit.

I've described (smp_)read_barrier_depends().

I've rearranged the order of the sections, so that memory barriers are
discussed in abstract first, and then described the memory barrier facilities
available on Linux, before going on to more real-world discussions and examples.

I've added information about the lack of memory barriering effects with atomic
ops and bitops.

I've added information about control dependencies.

I've added more diagrams to illustrate caching interactions between CPUs.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-31 12:27:01 -08:00
..
DocBook [PATCH] libata: Simplex and other mode filtering logic 2006-03-29 19:30:28 -05:00
RCU [PATCH] for_each_possible_cpu: documentaion 2006-03-28 09:16:05 -08:00
aoe [PATCH] aoe [2/8]: support dynamic resizing of AoE devices 2006-03-23 22:01:55 -08:00
arm [ARM] 3416/1: Update LART site URL 2006-03-27 15:32:30 +01:00
block [PATCH] update max_sectors documentation 2006-03-27 09:29:01 +02:00
cdrom [PATCH] remove verify_area(): remove or edit references to verify_area in Documentation/ 2005-09-07 16:57:35 -07:00
connector [CONNECTOR]: Use netlink_has_listeners() to avoind unnecessary allocations. 2006-03-20 22:21:40 -08:00
cpu-freq [PATCH] cpufreq: documentation for 'ondemand' and 'conservative' 2005-12-01 01:23:23 -08:00
cris Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
crypto [PATCH] Spelling fixes for Documentation/ 2005-09-10 10:06:28 -07:00
device-mapper [PATCH] Fix dm-snapshot tutorial in Documentation 2005-11-07 07:53:54 -08:00
driver-model [PATCH] Clean up Documentation/driver-model/overview.txt 2006-02-03 08:31:59 -08:00
drivers/edac [PATCH] EDAC: documentation spelling fixes 2006-03-26 08:57:08 -08:00
dvb Documentation/dvb/get_dvb_firmware: fix firmware URL 2006-03-22 00:43:59 +01:00
early-userspace earlyuserspace/README: fix homonym err 2005-11-08 17:16:50 +01:00
fb [PATCH] Update cyblafb driver 2006-01-09 10:00:36 -08:00
filesystems [PATCH] Docs update: missing files and descriptions for filesystems/00-INDEX 2006-03-28 09:16:06 -08:00
firmware_class [PATCH] Doc: fix example firmware source code 2006-03-25 08:23:01 -08:00
fujitsu/frv [PATCH] FRV: Use virtual interrupt disablement 2006-02-14 16:09:35 -08:00
hwmon [PATCH] w83781d: Don't reset the chip by default 2006-03-23 14:21:53 -08:00
i2c [PATCH] I2C: i2c-piix4: Add Broadcom HT-1000 support 2006-03-23 14:21:55 -08:00
i2o spelling: s/retreive/retrieve/ 2006-01-10 00:10:13 +01:00
i386 [PATCH] Make the bzImage format self-terminating 2005-09-07 16:57:29 -07:00
ia64 [IA64] Add Documentation/ia64/mca.txt 2005-09-16 10:34:16 -07:00
infiniband [PATCH] IB: Add core locking documentation to Infiniband 2005-07-27 16:26:15 -07:00
input Fix "stuct", "strut", "struc" typos 2006-01-15 02:12:54 +01:00
ioctl spelling: s/appropiate/appropriate/ 2006-01-15 02:00:17 +01:00
isdn Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
kbuild kbuild: in makefile.txt note that Makefile is preferred name for kbuild files 2006-03-10 00:23:32 +01:00
kdump [PATCH] kdump: add dmesg gdbmacro into document 2006-01-11 18:42:10 -08:00
m68k [PATCH] Typo fixes 2006-03-28 09:16:08 -08:00
mips [MIPS] Update docs to reflect the latest status of the Alchemy IDE driver. 2006-02-14 19:13:23 +00:00
networking Merge branch 'upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-2.6 2006-03-29 17:30:19 -05:00
parisc Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
pcmcia [PATCH] pcmcia: unify attach, EVENT_CARD_INSERTION handlers into one probe callback 2006-01-06 00:03:24 +01:00
power [PATCH] swsusp: userland interface 2006-03-23 07:38:07 -08:00
powerpc [PATCH] powerpc: Kill _machine and hard-coded platform numbers 2006-03-28 23:15:54 +11:00
s390 [PATCH] s390: cio documentation update 2006-03-24 07:33:15 -08:00
scsi [SCSI] megaraid_sas: support for 1078 type controller added 2006-02-04 16:38:41 -06:00
serial [SERIAL] Update serial_core documentation 2005-10-31 11:53:19 +00:00
sh Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
sound [PATCH] more s/fucn/func/ typo fixes 2006-03-26 08:57:09 -08:00
sparc Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
spi [PATCH] SPI: spi_butterfly, restore lost deltas 2006-02-06 12:17:17 -08:00
sysctl [PATCH] suspend-to-ram: allow video options to be set at runtime 2006-02-20 20:00:10 -08:00
telephony Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
uml [PATCH] Spelling fixes for Documentation/ 2005-09-10 10:06:28 -07:00
usb [PATCH] USB: ZC0301 driver bugfix 2006-03-20 14:50:01 -08:00
video4linux V4L/DVB (3599c): Whitespace cleanups under Documentation/video4linux 2006-03-25 09:29:32 -03:00
vm [PATCH] Page migration documentation update 2006-03-14 21:43:02 -08:00
w1 [PATCH] W1: Add the DS2482 I2C-to-w1 bridge driver. 2006-03-23 17:28:12 -08:00
watchdog [PATCH] ppc32: Added support for the Book-E style Watchdog Timer 2005-09-05 00:05:56 -07:00
x86_64 [PATCH] x86_64: Better ATI timer fix 2006-02-26 09:53:31 -08:00
00-INDEX [PATCH] update Documentation/00-INDEX 2005-11-18 10:51:22 -08:00
BUG-HUNTING Documentation: Update to BUG-HUNTING 2006-03-22 00:37:42 +01:00
Changes Documentation/Changes: remove outdated translation references 2006-03-20 20:28:13 +01:00
CodingStyle [PATCH] CodingStyle correction 2006-01-10 08:01:52 -08:00
DMA-API.txt [PATCH] Spelling fixes for Documentation/ 2005-09-10 10:06:28 -07:00
DMA-ISA-LPC.txt [PATCH] ISA DMA API documentation 2005-09-09 14:03:42 -07:00
DMA-mapping.txt [PATCH] Replace 0xff.. with correct DMA_xBIT_MASK 2006-03-28 09:16:07 -08:00
HOWTO [PATCH] Add HOWTO do kernel development document to the Documentation directory 2005-11-18 10:51:21 -08:00
IO-mapping.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
IPMI.txt [PATCH] ipmi poweroff: fix chassis control 2005-09-07 16:57:49 -07:00
IRQ-affinity.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
MSI-HOWTO.txt [PATCH] Doc/MSI-HOWTO: cleanups 2005-11-07 07:53:55 -08:00
ManagementStyle Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
PCIEBUS-HOWTO.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
README.DAC960 Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
README.cycladesZ Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
SAK.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
SecurityBugs Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
SubmittingDrivers [PATCH] docs: update some updated code docs 2006-01-14 10:39:53 -08:00
SubmittingPatches [PATCH] docs: update some updated code docs 2006-01-14 10:39:53 -08:00
VGA-softcursor.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
acpi-hotkey.txt Merge to-linus-stable into to-akpm 2005-08-15 15:52:00 -04:00
applying-patches.txt [PATCH] Docs update: typos, corrections and additions to applying-patches.txt 2006-01-10 08:01:54 -08:00
atomic_ops.txt [PATCH] atomic: inc_not_zero 2005-11-13 18:14:16 -08:00
basic_profiling.txt [PATCH] oprofile: report anonymous region samples 2005-06-24 00:06:27 -07:00
binfmt_misc.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
cachetlb.txt [PATCH] Add flush_kernel_dcache_page() API 2006-03-26 08:56:53 -08:00
cciss.txt [SCSI] cciss: scsi error handling 2005-11-06 14:12:49 -06:00
cli-sti-removal.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
computone.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
cpqarray.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
cpu-hotplug.txt [PATCH] for_each_possible_cpu: documentaion 2006-03-28 09:16:05 -08:00
cpusets.txt [PATCH] cpuset memory spread basic implementation 2006-03-24 07:33:22 -08:00
cputopology.txt [PATCH] trivial typos in Documentation/cputopology.txt 2006-03-28 09:16:08 -08:00
dcdbas.txt [PATCH] dcdbas: add Dell Systems Management Base Driver with sysfs support 2005-09-07 16:57:27 -07:00
debugging-modules.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
dell_rbu.txt [PATCH] dell_rbu: changes in packet update mechanism 2005-10-11 09:46:53 -07:00
devices.txt [PATCH] USB: Delete leftovers from bluetty driver 2005-11-17 11:29:53 -08:00
digiepca.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
dnotify.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
dontdiff [PATCH] dontdiff: add asm_offsets 2005-09-13 08:22:29 -07:00
eisa.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
exception.txt [PATCH] remove verify_area(): remove or edit references to verify_area in Documentation/ 2005-09-07 16:57:35 -07:00
feature-removal-schedule.txt [PATCH] fs/namei.c: make lookup_hash() static 2006-03-31 12:19:01 -08:00
floppy.txt [PATCH] kernel Doc/ URL corrections 2005-11-22 09:14:30 -08:00
ftape.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
hayes-esp.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
highuid.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
hpet.txt Documentation/hpet.txt typo 2006-01-15 02:09:54 +01:00
hrtimers.txt [PATCH] hrtimer: hrtimer documentation 2006-01-10 08:01:37 -08:00
hw_random.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
ibm-acpi.txt [ACPI] IBM ThinkPad ACPI Extras Driver v0.12 2005-08-25 17:37:51 -04:00
ide.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
initrd.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
io_ordering.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
ioctl-number.txt [PATCH] arch/i386/kernel/microcode.c: remove the obsolete microcode_ioctl 2006-03-28 09:16:06 -08:00
iostats.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
isapnp.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
java.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
kernel-doc-nano-HOWTO.txt [PATCH] Doc/kernel-doc: add more usage info 2006-02-01 08:53:27 -08:00
kernel-docs.txt [PATCH] kernel Doc/ URL corrections 2005-11-22 09:14:30 -08:00
kernel-parameters.txt [PATCH] doc: more serial-console info 2006-03-25 08:23:00 -08:00
keys-request-key.txt [PATCH] keys: Permit running process to instantiate keys 2006-01-08 20:13:53 -08:00
keys.txt [PATCH] keys: Permit running process to instantiate keys 2006-01-08 20:13:53 -08:00
kobject.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
kprobes.txt [PATCH] kprobes: Update Documentation/kprobes.txt 2006-02-14 16:09:34 -08:00
kref.txt [PATCH] kref: add link to original documentation to the kref documentation. 2005-04-18 21:57:30 -07:00
laptop-mode.txt spelling: s/appropiate/appropriate/ 2006-01-15 02:00:17 +01:00
ldm.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
leds-class.txt [PATCH] LED: class documentation 2006-03-31 12:18:56 -08:00
locks.txt [PATCH] Docs update: remove obsolete patch from locks.txt 2006-01-10 08:01:54 -08:00
logo.gif Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
logo.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
magic-number.txt [PATCH] mm: rename kmem_cache_s to kmem_cache 2005-11-07 07:53:24 -08:00
mandatory.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mca.txt [PATCH] kernel Doc/ URL corrections 2005-11-22 09:14:30 -08:00
md.txt [PATCH] md: allow sync-speed to be controlled per-device 2006-01-06 08:34:10 -08:00
memory-barriers.txt [PATCH] Document Linux's memory barriers [try #7] 2006-03-31 12:27:01 -08:00
memory.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mono.txt [PATCH] merge some from Rusty's trivial patches 2005-09-10 10:06:30 -07:00
moxa-smartio Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mtrr.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mutex-design.txt [PATCH] mutex subsystem, documentation 2006-01-09 15:59:20 -08:00
nbd.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
nfsroot.txt [PATCH] Updated Documentation/nfsroot.txt 2006-03-24 07:33:27 -08:00
nmi_watchdog.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
nommu-mmap.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
numastat.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
oops-tracing.txt [PATCH] doc: refer to kdump in oops-tracing.txt 2006-01-11 18:42:10 -08:00
paride.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
parport-lowlevel.txt [PATCH] parport: fix documentation 2006-02-03 08:32:06 -08:00
parport.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
pci-error-recovery.txt [PATCH] Documentation: Updated PCI Error Recovery 2006-02-03 08:32:00 -08:00
pci.txt [PATCH] merge some from Rusty's trivial patches 2005-09-10 10:06:30 -07:00
pm.txt [ACPI] linux-acpi@vger.kernel.org replaces acpi-devel@lists.sourceforge.net 2006-01-06 16:19:26 -05:00
pnp.txt [PATCH] pnp: PNP: adjust pnp_register_driver signature 2006-03-27 08:44:53 -08:00
preempt-locking.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
prio_tree.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
ramdisk.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
riscom8.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
robust-futex-ABI.txt [PATCH] lightweight robust futexes updates 2006-03-27 08:44:49 -08:00
robust-futexes.txt [PATCH] lightweight robust futexes updates 2006-03-27 08:44:49 -08:00
rocket.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
rpc-cache.txt [PATCH] knfsd: Update rpc-cache.txt to match recent changes 2006-03-27 08:44:43 -08:00
rtc.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
sched-arch.txt [PATCH] sched: resched and cpu_idle rework 2005-11-09 07:56:33 -08:00
sched-coding.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
sched-design.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
sched-domains.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
sched-stats.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
seclvl.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
serial-console.txt [PATCH] doc: more serial-console info 2006-03-25 08:23:00 -08:00
sgi-ioc4.txt [PATCH] ioc4: Core driver rewrite 2005-06-21 18:46:32 -07:00
sgi-visws.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
sharedsubtree.txt [PATCH] Complete description of shared subtrees. 2005-11-07 18:18:11 -08:00
smart-config.txt kbuild: remove checkconfig.pl 2006-02-19 09:51:22 +01:00
smp.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
sonypi.txt [PATCH] sonypi SPIC initialisation fix 2005-09-07 16:57:24 -07:00
sparse.txt [PATCH] Documentation/sparse.txt: mention CF=-Wbitwise 2005-11-07 07:53:54 -08:00
specialix.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
spinlocks.txt fix rwlock usage example 2006-03-22 00:19:39 +01:00
stable_api_nonsense.txt [PATCH] stable_api_nonsense.txt fixes 2005-07-29 13:12:49 -07:00
stable_kernel_rules.txt [PATCH] Docs update: small fixes to stable_kernel_rules.txt 2006-01-10 08:01:55 -08:00
stallion.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
svga.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
sx.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
sysrq.txt update for Documentation/sysrq.txt 2006-01-03 13:31:01 +01:00
time_interpolators.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
tipar.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
tty.txt [PATCH] Introduce tty_unregister_ldisc() 2005-06-23 09:45:35 -07:00
unicode.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
unshare.txt [PATCH] unshare system call -v5: Documentation file 2006-02-07 16:12:34 -08:00
voyager.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
xterm-linux.xpm Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
zorro.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00

README.cycladesZ

The Cyclades-Z must have firmware loaded onto the card before it will
operate.  This operation should be performed during system startup,

The firmware, loader program and the latest device driver code are
available from Cyclades at
    ftp://ftp.cyclades.com/pub/cyclades/cyclades-z/linux/