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Yu Kuai 84a578961b md/raid10: prevent soft lockup while flush writes
[ Upstream commit 010444623e ]

Currently, there is no limit for raid1/raid10 plugged bio. While flushing
writes, raid1 has cond_resched() while raid10 doesn't, and too many
writes can cause soft lockup.

Follow up soft lockup can be triggered easily with writeback test for
raid10 with ramdisks:

watchdog: BUG: soft lockup - CPU#10 stuck for 27s! [md0_raid10:1293]
Call Trace:
 <TASK>
 call_rcu+0x16/0x20
 put_object+0x41/0x80
 __delete_object+0x50/0x90
 delete_object_full+0x2b/0x40
 kmemleak_free+0x46/0xa0
 slab_free_freelist_hook.constprop.0+0xed/0x1a0
 kmem_cache_free+0xfd/0x300
 mempool_free_slab+0x1f/0x30
 mempool_free+0x3a/0x100
 bio_free+0x59/0x80
 bio_put+0xcf/0x2c0
 free_r10bio+0xbf/0xf0
 raid_end_bio_io+0x78/0xb0
 one_write_done+0x8a/0xa0
 raid10_end_write_request+0x1b4/0x430
 bio_endio+0x175/0x320
 brd_submit_bio+0x3b9/0x9b7 [brd]
 __submit_bio+0x69/0xe0
 submit_bio_noacct_nocheck+0x1e6/0x5a0
 submit_bio_noacct+0x38c/0x7e0
 flush_pending_writes+0xf0/0x240
 raid10d+0xac/0x1ed0

Fix the problem by adding cond_resched() to raid10 like what raid1 did.

Note that unlimited plugged bio still need to be optimized, for example,
in the case of lots of dirty pages writeback, this will take lots of
memory and io will spend a long time in plug, hence io latency is bad.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230529131106.2123367-2-yukuai1@huaweicloud.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-01 13:21:55 +01:00
Documentation platform/x86: asus-wmi: Document the dgpu_disable sysfs attribute 2024-03-01 13:21:52 +01:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
arch powerpc/eeh: Set channel state after notifying the drivers 2024-03-01 13:21:53 +01:00
block blk-iocost: Fix an UBSAN shift-out-of-bounds warning 2024-02-23 08:54:59 +01:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:22:01 +02:00
crypto crypto: api - Disallow identical driver names 2024-02-23 08:54:23 +01:00
drivers md/raid10: prevent soft lockup while flush writes 2024-03-01 13:21:55 +01:00
fs cifs: remove useless parameter 'is_fsctl' from SMB2_ioctl() 2024-03-01 13:21:53 +01:00
include PM: core: Remove static qualifier in DEFINE_SIMPLE_DEV_PM_OPS macro 2024-03-01 13:21:54 +01:00
init rootfs: Fix support for rootfstype= when root= is given 2024-01-25 14:52:48 -08:00
io_uring io_uring/rw: ensure io->bytes_done is always initialized 2024-01-25 14:52:48 -08:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:28:45 +01:00
kernel sched/rt: Disallow writing invalid values to sched_rt_period_us 2024-03-01 13:21:43 +01:00
lib debugobjects: Recheck debug_objects_enabled before reporting 2024-03-01 13:21:54 +01:00
mm userfaultfd: fix mmap_changing checking in mfill_atomic_hugetlb 2024-03-01 13:21:43 +01:00
net netfilter: nf_tables: add rescheduling points during loop detection walks 2024-03-01 13:21:54 +01:00
samples samples/hw_breakpoint: fix building without module unloading 2023-09-23 11:10:01 +02:00
scripts scripts/decode_stacktrace.sh: optionally use LLVM utilities 2024-02-23 08:55:13 +01:00
security lsm: fix the logic in security_inode_getsecctx() 2024-02-23 08:55:05 +01:00
sound ALSA: usb-audio: Ignore clock selector errors for single connection 2024-03-01 13:21:45 +01:00
tools tools/virtio: fix build 2024-03-01 13:21:52 +01:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2022-02-01 17:27:15 +01:00
virt KVM: Grab a reference to KVM for VM and vCPU stats file descriptors 2023-08-03 10:22:40 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: add Andrej Shadura 2021-10-18 20:22:03 -10:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS iio: stx104: Move to addac subdirectory 2023-08-26 14:23:27 +02:00
Makefile Linux 5.15.149 2024-02-23 08:55:16 +01:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.