linux/include
Jens Axboe 18ce3751cc Properly notify block layer of sync writes
fsync_buffers_list() and sync_dirty_buffer() both issue async writes and
then immediately wait on them. Conceptually, that makes them sync writes
and we should treat them as such so that the IO schedulers can handle
them appropriately.

This patch fixes a write starvation issue that Lin Ming reported, where
xx is stuck for more than 2 minutes because of a large number of
synchronous IO in the system:

INFO: task kjournald:20558 blocked for more than 120 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this
message.
kjournald     D ffff810010820978  6712 20558      2
ffff81022ddb1d10 0000000000000046 ffff81022e7baa10 ffffffff803ba6f2
ffff81022ecd0000 ffff8101e6dc9160 ffff81022ecd0348 000000008048b6cb
0000000000000086 ffff81022c4e8d30 0000000000000000 ffffffff80247537
Call Trace:
[<ffffffff803ba6f2>] kobject_get+0x12/0x17
[<ffffffff80247537>] getnstimeofday+0x2f/0x83
[<ffffffff8029c1ac>] sync_buffer+0x0/0x3f
[<ffffffff8066d195>] io_schedule+0x5d/0x9f
[<ffffffff8029c1e7>] sync_buffer+0x3b/0x3f
[<ffffffff8066d3f0>] __wait_on_bit+0x40/0x6f
[<ffffffff8029c1ac>] sync_buffer+0x0/0x3f
[<ffffffff8066d48b>] out_of_line_wait_on_bit+0x6c/0x78
[<ffffffff80243909>] wake_bit_function+0x0/0x23
[<ffffffff8029e3ad>] sync_dirty_buffer+0x98/0xcb
[<ffffffff8030056b>] journal_commit_transaction+0x97d/0xcb6
[<ffffffff8023a676>] lock_timer_base+0x26/0x4b
[<ffffffff8030300a>] kjournald+0xc1/0x1fb
[<ffffffff802438db>] autoremove_wake_function+0x0/0x2e
[<ffffffff80302f49>] kjournald+0x0/0x1fb
[<ffffffff802437bb>] kthread+0x47/0x74
[<ffffffff8022de51>] schedule_tail+0x28/0x5d
[<ffffffff8020cac8>] child_rip+0xa/0x12
[<ffffffff80243774>] kthread+0x0/0x74
[<ffffffff8020cabe>] child_rip+0x0/0x12

Lin Ming confirms that this patch fixes the issue. I've run tests with
it for the past week and no ill effects have been observed, so I'm
proposing it for inclusion into 2.6.26.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-07-01 09:07:34 +02:00
..
acpi proper prototype for acpi_processor_tstate_has_changed() 2008-06-11 19:13:46 -04:00
asm-alpha alpha: fix compile error in arch/alpha/mm/init.c 2008-06-23 18:26:04 -07:00
asm-arm [ARM] 5091/1: Add missing bitfield include to regs-lcd.h 2008-06-12 20:49:38 +01:00
asm-avr32 avr32: types: use <asm-generic/int-*.h> for the avr32 architecture 2008-05-02 16:18:20 -07:00
asm-blackfin Blackfin Serial Driver: Use timer to poll CTS PIN instead of workqueue. 2008-06-19 17:46:39 +08:00
asm-cris cris: types: use <asm-generic/int-*.h> for the cris architecture 2008-05-02 16:18:20 -07:00
asm-frv FRV: ip_fast_csum() requires a memory clobber on its inline asm 2008-06-05 10:31:21 -07:00
asm-generic kbuild: fix a.out.h export to userspace with O= build. 2008-06-27 23:13:54 +02:00
asm-h8300 h8300: fix typo in header guard 2008-06-06 11:29:12 -07:00
asm-ia64 [IA64] Fix CONFIG_IA64_SGI_UV build error 2008-06-16 09:02:03 -07:00
asm-m32r asm-m32r/uaccess.h must #include <asm/setup.h> 2008-06-06 11:29:13 -07:00
asm-m68k m68k: Add ext2_find_{first,next}_bit() for ext4 2008-06-12 18:05:39 -07:00
asm-m68knommu m68knommu: rework definition of HZ 2008-05-01 08:08:36 -07:00
asm-mips [MIPS] Malta: Fix build errors for 64-bit kernels 2008-06-16 15:14:48 +01:00
asm-mn10300 MN10300: Fix typo in header guard 2008-05-28 07:59:06 -07:00
asm-parisc parisc: fix miscompilation of ip_fast_csum with gcc >= 4.3 2008-06-13 10:49:56 -04:00
asm-powerpc kbuild: fix a.out.h export to userspace with O= build. 2008-06-27 23:13:54 +02:00
asm-ppc [POWERPC] ppc: More compile fixes 2008-05-12 22:57:51 +10:00
asm-s390 [S390] Fix __ctl_load/__ctl_store inline assembly constraints 2008-06-10 10:03:28 +02:00
asm-sh sh: fix miscompilation of ip_fast_csum with gcc >= 4.3 2008-06-02 12:40:14 +09:00
asm-sparc sparc: remove CVS keywords 2008-05-20 00:33:44 -07:00
asm-sparc64 sparc64: IO accessors fix 2008-05-30 02:01:28 -07:00
asm-um uml: activate_mm: remove the dead PF_BORROWED_MM check 2008-06-06 11:36:22 -07:00
asm-v850 v850: fix typo in header guard 2008-06-06 11:29:12 -07:00
asm-x86 Merge branch 'kvm-updates-2.6.26' of git://git.kernel.org/pub/scm/linux/kernel/git/avi/kvm 2008-06-24 18:09:06 -07:00
asm-xtensa asm-{alpha,h8300,um,v850,xtensa}/param.h: unbreak HZ for userspace 2008-05-14 19:11:14 -07:00
crypto [CRYPTO] api: Fix scatterwalk_sg_chain 2008-05-01 18:22:28 +08:00
keys
linux Properly notify block layer of sync writes 2008-07-01 09:07:34 +02:00
math-emu
media V4L/DVB (8092): videodev: simplify and fix standard enumeration 2008-06-26 15:58:57 -03:00
mtd
net netns: Don't receive new packets in a dead network namespace. 2008-06-20 22:16:51 -07:00
pcmcia
rdma IB/core: Remove IB_DEVICE_SEND_W_INV capability flag 2008-06-09 09:58:42 -07:00
rxrpc
scsi Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6 2008-05-02 13:52:35 -07:00
sound [ALSA] ac97 - Fix ASUS A9T laptop output 2008-05-30 16:20:42 +02:00
video fbdev: platforming hecubafb and n411 2008-04-28 08:58:41 -07:00
xen x86: Make xen use the paravirt clocksource structs and functions 2008-06-24 21:02:32 +03:00
Kbuild