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Naohiro Aota 2761ece893 btrfs: introduce offload_csum_mode to tweak checksum offloading behavior
We disable offloading checksum to workqueues and do it synchronously when
the checksum algorithm is fast. However, as reported in the link below,
RAID0 with multiple devices may suffer from the sync checksum, because
"fast checksum" is still not fast enough to catch up with RAID0 writing.

We don't have an effective way to determine whether to offload or not,
for now add a sysfs knob so this can be debugged. This is intentionally
under CONFIG_BTRFS_DEBUG so ti's not exposed to users as it may be
removed in the future agin.

Introduce fs_devices->offload_csum_mode, so that a btrfs developer can
change the behavior by writing to /sys/fs/btrfs/<uuid>/offload_csum. The
default is "auto" which is the same as the previous behavior. Or, you
can set "on" or "off" (or "y" or "n" whatever kstrtobool() accepts) to
always/never offload checksum.

More benchmark need to be collected with this knob to implement a proper
criteria to enable/disable checksum offloading.

Link: https://lore.kernel.org/linux-btrfs/20230731152223.4EFB.409509F4@e16-tech.com/
Link: https://lore.kernel.org/linux-btrfs/p3vo3g7pqn664mhmdhlotu5dzcna6vjtcoc2hb2lsgo2fwct7k@xzaxclba5tae/
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-03-04 16:24:52 +01:00
Documentation Including fixes from bluetooth, WiFi and netfilter. 2024-02-29 12:40:20 -08:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
arch powerpc fixes for 6.8 #5 2024-03-03 09:47:19 -08:00
block block: sed-opal: handle empty atoms when parsing response 2024-02-16 15:52:45 -07:00
certs This update includes the following changes: 2023-11-02 16:15:30 -10:00
crypto crypto: lskcipher - Copy IV in lskcipher glue code always 2024-02-24 08:37:24 +08:00
drivers phy second set of fixes for 6.8 2024-03-03 09:56:49 -08:00
fs btrfs: introduce offload_csum_mode to tweak checksum offloading behavior 2024-03-04 16:24:52 +01:00
include block: define bvec_iter as __packed __aligned(4) 2024-03-02 09:15:01 -08:00
init update workarounds for gcc "asm goto" issue 2024-02-15 11:14:33 -08:00
io_uring io_uring/net: fix multishot accept overflow handling 2024-02-14 18:30:19 -07:00
ipc shm: Slim down dependencies 2023-12-20 19:26:31 -05:00
kernel Probes fixes for v6.8-rc5: 2024-03-01 11:17:23 -08:00
lib Including fixes from bluetooth, WiFi and netfilter. 2024-02-29 12:40:20 -08:00
mm 6 hotfixes. 3 are cc:stable and the remainder address post-6.7 issues 2024-02-27 16:44:15 -08:00
net bluetooth pull request for net: 2024-02-29 09:10:24 -08:00
rust Rust changes for v6.8 2024-01-11 13:05:41 -08:00
samples work around gcc bugs with 'asm goto' with outputs 2024-02-09 15:57:48 -08:00
scripts RISC-V Fixes for 6.8-rc7 2024-03-01 12:44:33 -08:00
security tomoyo: fix UAF write bug in tomoyo_write_control() 2024-03-01 11:14:00 -08:00
sound ASoC: Fixes for v6.8 2024-02-29 08:29:04 +01:00
tools powerpc fixes for 6.8 #5 2024-03-03 09:47:19 -08:00
usr Kbuild updates for v6.8 2024-01-18 17:57:07 -08:00
virt Generic: 2024-01-17 13:03:37 -08:00
.clang-format clang-format: Update with v6.7-rc4's `for_each` macro list 2023-12-08 23:54:38 +01:00
.cocciconfig
.editorconfig Add .editorconfig file for basic formatting 2023-12-28 16:22:47 +09:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore Add .editorconfig file for basic formatting 2023-12-28 16:22:47 +09:00
.mailmap MAINTAINERS: mailmap: update Shakeel's email address 2024-02-20 14:20:50 -08:00
.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 MAINTAINERS: supplement of zswap maintainers update 2024-01-25 23:52:21 -08:00
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 RISC-V Fixes for 6.8-rc7 2024-03-01 12:44:33 -08:00
Makefile Linux 6.8-rc7 2024-03-03 13:02:52 -08:00
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.