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Filipe Manana 2e438442ba btrfs: remove not needed mod_start and mod_len from struct extent_map 
The mod_start and mod_len fields of struct extent_map were introduced by
commit 4e2f84e63d ("Btrfs: improve fsync by filtering extents that we
want") in order to avoid too low performance when fsyncing a file that
keeps getting extent maps merge, because it resulted in each fsync logging
again csum ranges that were already merged before.

We don't need this anymore as extent maps in the list of modified extents
are never merged with other extent maps and once we log an extent map we
remove it from the list of modified extent maps, so it's never logged
twice.

So remove the mod_start and mod_len fields from struct extent_map and use
instead the start and len fields when logging checksums in the fast fsync
path. This also makes EXTENT_FLAG_FILLING unused so remove it as well.

Running the reproducer from the commit mentioned before, with a larger
number of extents and against a null block device, so that IO is fast
and we can better see any impact from searching checksums items and
logging them, gave the following results from dd:

Before this change:

   409600000 bytes (410 MB, 391 MiB) copied, 22.948 s, 17.8 MB/s

After this change:

   409600000 bytes (410 MB, 391 MiB) copied, 22.9997 s, 17.8 MB/s

So no changes in throughput.
The test was done in a release kernel (non-debug, Debian's default kernel
config) and its steps are the following:

   $ mkfs.btrfs -f /dev/nullb0
   $ mount /dev/sdb /mnt
   $ dd if=/dev/zero of=/mnt/foobar bs=4k count=100000 oflag=sync
   $ umount /mnt

This also reduces the size of struct extent_map from 128 bytes down to 112
bytes, so now we can have 36 extents maps per 4K page instead of 32.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-05-07 21:31:02 +02:00
arch powerpc fixes for 6.9 #4 2024-05-05 10:44:04 -07:00
block vfs-6.9-rc6.fixes 2024-04-26 11:01:28 -07:00
certs This update includes the following changes: 2023-11-02 16:15:30 -10:00
crypto This push fixes a regression that broke iwd as well as a divide by 2024-03-25 10:48:23 -07:00
Documentation Char/Misc driver fixes for 6.9-rc7 2024-05-05 10:08:52 -07:00
drivers Reapply "drm/qxl: simplify qxl_fence_wait" 2024-05-06 13:28:59 -07:00
fs btrfs: remove not needed mod_start and mod_len from struct extent_map 2024-05-07 21:31:02 +02:00
include btrfs: remove not needed mod_start and mod_len from struct extent_map 2024-05-07 21:31:02 +02:00
init Rust fixes for v6.9 2024-04-27 12:11:55 -07:00
io_uring io_uring/net: restore msg_control on sendzc retry 2024-04-08 21:48:41 -06:00
ipc sysctl changes for v6.9-rc1 2024-03-18 14:59:13 -07:00
kernel Fix suspicious RCU usage in __do_softirq(). 2024-05-05 10:12:32 -07:00
lib Char/Misc driver fixes for 6.9-rc7 2024-05-05 10:08:52 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm/slub: avoid zeroing outside-object freepointer for single free 2024-05-01 17:28:56 +02:00
net Including fixes from bpf. 2024-05-02 08:51:47 -07:00
rust rust: remove params from module macro example 2024-04-25 17:34:33 +02:00
samples Tracing updates for 6.9: 2024-03-18 15:11:44 -07:00
scripts Rust fixes for v6.9 2024-04-27 12:11:55 -07:00
security security: Place security_path_post_mknod() where the original IMA call was 2024-04-03 10:21:32 -07:00
sound ALSA: hda/realtek: Fix build error without CONFIG_PM 2024-05-02 08:25:06 +02:00
tools cxl fix for v6.9-rc7 2024-05-03 16:21:05 -07:00
usr Kbuild updates for v6.8 2024-01-18 17:57:07 -08:00
virt KVM: Drop unused @may_block param from gfn_to_pfn_cache_invalidate_start() 2024-04-11 12:58:53 -07:00
.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 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 2024-04-26 17:36:53 -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 MAINTAINERS: Drop Gustavo Pimentel as PCI DWC Maintainer 2024-03-27 13:41:02 -05:00
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 Including fixes from bpf. 2024-05-02 08:51:47 -07:00
Makefile Linux 6.9-rc7 2024-05-05 14:06:01 -07:00
README README: Fix spelling 2024-03-18 03:36:32 -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 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.