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Ming Lei 872a2b3182 blk-mq: insert request not through ->queue_rq into sw/scheduler queue
[ Upstream commit db03f88fae ]

c616cbee97 ("blk-mq: punt failed direct issue to dispatch list") supposed
to add request which has been through ->queue_rq() to the hw queue dispatch
list, however it adds request running out of budget or driver tag to hw queue
too. This way basically bypasses request merge, and causes too many request
dispatched to LLD, and system% is unnecessary increased.

Fixes this issue by adding request not through ->queue_rq into sw/scheduler
queue, and this way is safe because no ->queue_rq is called on this request
yet.

High %system can be observed on Azure storvsc device, and even soft lock
is observed. This patch reduces %system during heavy sequential IO,
meantime decreases soft lockup risk.

Fixes: c616cbee97 ("blk-mq: punt failed direct issue to dispatch list")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-09-03 11:26:54 +02:00
arch s390/numa: set node distance to LOCAL_DISTANCE 2020-09-03 11:26:50 +02:00
block blk-mq: insert request not through ->queue_rq into sw/scheduler queue 2020-09-03 11:26:54 +02:00
certs PKCS#7: Refactor verify_pkcs7_signature() 2019-08-05 18:40:18 -04:00
crypto crypto: algif_aead - fix uninitialized ctx->init 2020-08-21 13:05:38 +02:00
Documentation kbuild: support LLVM=1 to switch the default tools to Clang/LLVM 2020-08-26 10:40:47 +02:00
drivers hwmon: (nct7904) Correct divide by 0 2020-09-03 11:26:54 +02:00
fs btrfs: only commit delayed items at fsync if we are logging a directory 2020-09-03 11:26:51 +02:00
include efi: provide empty efi_enter_virtual_mode implementation 2020-09-03 11:26:49 +02:00
init x86: Fix early boot crash on gcc-10, third try 2020-05-20 08:20:34 +02:00
ipc ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2020-05-20 08:20:16 +02:00
kernel sched/uclamp: Fix a deadlock when enabling uclamp static key 2020-09-03 11:26:49 +02:00
lib test_kmod: avoid potential double free in trigger_config_run_type() 2020-08-21 13:05:37 +02:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm mm/vunmap: add cond_resched() in vunmap_pmd_range 2020-09-03 11:26:52 +02:00
net net/sched: act_ct: Fix skb double-free in tcf_ct_handle_fragments() error flow 2020-09-03 11:26:40 +02:00
samples bpf: Fix fds_example SIGSEGV error 2020-08-19 08:16:03 +02:00
scripts kconfig: qconf: fix signal connection to invalid slots 2020-08-26 10:41:04 +02:00
security Smack: prevent underflow in smk_set_cipso() 2020-08-19 08:16:16 +02:00
sound ALSA: usb-audio: Add capture support for Saffire 6 (USB 1.1) 2020-09-03 11:26:53 +02:00
tools selftests/powerpc: Purge extra count_pmc() calls of ebb selftests 2020-09-03 11:26:44 +02:00
usr initramfs: restore default compression behavior 2020-04-08 09:08:38 +02:00
virt KVM: arm64: Only reschedule if MMU_NOTIFIER_RANGE_BLOCKABLE is not set 2020-08-26 10:41:08 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes
.gitignore Modules updates for v5.4 2019-09-22 10:34:46 -07:00
.mailmap ARM: SoC fixes 2019-11-10 13:41:59 -08:00
COPYING
CREDITS MAINTAINERS: Remove Simon as Renesas SoC Co-Maintainer 2019-10-10 08:12:51 -07:00
Kbuild kbuild: do not descend to ./Kbuild when cleaning 2019-08-21 21:03:58 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS Documentation/llvm: add documentation on building w/ Clang/LLVM 2020-08-26 10:40:46 +02:00
Makefile Linux 5.4.61 2020-08-26 10:41:08 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.