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Jan Kara 2f1f31042e nfs: Block on write congestion
Commit 6df25e5853 ("nfs: remove reliance on bdi congestion")
introduced NFS-private solution for limiting number of writes
outstanding against a particular server. Unlike previous bdi congestion
this algorithm actually works and limits number of outstanding writeback
pages to nfs_congestion_kb which scales with amount of client's memory
and is capped at 256 MB. As a result some workloads such as random
buffered writes over NFS got slower (from ~170 MB/s to ~126 MB/s). The
fio command to reproduce is:

fio --direct=0 --ioengine=sync --thread --invalidate=1 --group_reporting=1
  --runtime=300 --fallocate=posix --ramp_time=10 --new_group --rw=randwrite
  --size=64256m --numjobs=4 --bs=4k --fsync_on_close=1 --end_fsync=1

This happens because the client sends ~256 MB worth of dirty pages to
the server and any further background writeback request is ignored until
the number of writeback pages gets below the threshold of 192 MB. By the
time this happens and clients decides to trigger another round of
writeback, the server often has no pages to write and the disk is idle.

To fix this problem and make the client react faster to eased congestion
of the server by blocking waiting for congestion to resolve instead of
aborting writeback. This improves the random 4k buffered write
throughput to 184 MB/s.

Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2024-07-08 13:47:27 -04:00
arch powerpc fixes for 6.10 #4 2024-07-06 18:31:24 -07:00
block block: unmap and free user mapped integrity via submitter 2024-06-12 11:00:50 -06:00
certs kbuild: use $(src) instead of $(srctree)/$(src) for source directory 2024-05-10 04:34:52 +09:00
crypto This push fixes a bug in the new ecc P521 code as well as a buggy 2024-05-20 08:47:54 -07:00
Documentation RISC-V Fixes for 6.10-rc7 2024-07-05 12:22:51 -07:00
drivers A set of clk fixes for the Qualcomm, Mediatek, and Allwinner drivers: 2024-07-07 10:59:38 -07:00
fs nfs: Block on write congestion 2024-07-08 13:47:27 -04:00
include nfs: Block on write congestion 2024-07-08 13:47:27 -04:00
init gcc: disable '-Warray-bounds' for gcc-9 2024-06-15 10:43:04 -07:00
io_uring io_uring/net: don't clear msg_inq before io_recv_buf_select() needs it 2024-07-02 09:42:10 -06:00
ipc Mainly singleton patches, documented in their respective changelogs. 2024-05-19 14:02:03 -07:00
kernel mm: optimize the redundant loop of mm_update_owner_next() 2024-07-03 12:29:24 -07:00
lib hardening fixes for v6.10-rc6 2024-06-28 16:11:02 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm filemap: Convert generic_perform_write() to support large folios 2024-07-08 10:55:39 -04:00
net SUNRPC: avoid soft lockup when transmitting UDP to reachable server. 2024-07-08 13:47:24 -04:00
rust rust: avoid unused import warning in rusttest 2024-06-11 23:33:28 +02:00
samples tracing/treewide: Remove second parameter of __assign_str() 2024-05-22 20:14:47 -04:00
scripts kbuild: scripts/gdb: bring the "abspath" back 2024-06-27 04:20:32 +09:00
security integrity-v6.10-fix 2024-07-05 16:21:54 -07:00
sound ASoC: Fixes for v6.10 2024-06-26 22:02:55 +02:00
tools powerpc fixes for 6.10 #4 2024-07-06 18:31:24 -07:00
usr kbuild: use $(src) instead of $(srctree)/$(src) for source directory 2024-05-10 04:34:52 +09:00
virt KVM fixes for 6.10 2024-06-21 08:03:55 -04:00
.clang-format clang-format: Update with v6.7-rc4's for_each macro list 2023-12-08 23:54:38 +01:00
.cocciconfig
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: create a list of all built DTB files 2024-02-19 18:20:39 +09:00
.mailmap bpf-for-netdev 2024-06-14 17:57:10 -07:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS pci-v6.10-fixes-2 2024-07-05 12:33:00 -07:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS pci-v6.10-fixes-2 2024-07-05 12:33:00 -07:00
Makefile Linux 6.10-rc7 2024-07-07 14:23:46 -07:00
README README: Fix spelling 2024-03-18 03:36:32 -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 reStructuredText 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.