No description
Find a file
Jan Kara c10f778ddf fs: fix performance regression in clean_bdev_aliases()
Commit e64855c6cf ("fs: Add helper to clean bdev aliases under a bh
and use it") added a wrapper for clean_bdev_aliases() that invalidates
bdev aliases underlying a single buffer head.

However this has caused a performance regression for bonnie++ benchmark
on ext4 filesystem when delayed allocation is turned off (ext3 mode) -
average of 3 runs:

  Hmean SeqOut Char  164787.55 (  0.00%) 107189.06 (-34.95%)
  Hmean SeqOut Block 219883.89 (  0.00%) 168870.32 (-23.20%)

The reason for this regression is that clean_bdev_aliases() is slower
when called for a single block because pagevec_lookup() it uses will end
up iterating through the radix tree until it finds a page (which may
take a while) but we are only interested whether there's a page at a
particular index.

Fix the problem by using pagevec_lookup_range() instead which avoids the
needless iteration.

Fixes: e64855c6cf ("fs: Add helper to clean bdev aliases under a bh and use it")
Link: http://lkml.kernel.org/r/20170726114704.7626-5-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-06 17:27:26 -07:00
arch metag/numa: remove the unused parent_node() macro 2017-09-06 17:27:24 -07:00
block Char/Misc drivers for 4.14-rc1 2017-09-05 11:08:17 -07:00
certs
crypto
Documentation fscache: remove unused ->now_uncached callback 2017-09-06 17:27:26 -07:00
drivers zram: add config and doc file for writeback feature 2017-09-06 17:27:25 -07:00
firmware
fs fs: fix performance regression in clean_bdev_aliases() 2017-09-06 17:27:26 -07:00
include mm: implement find_get_pages_range() 2017-09-06 17:27:26 -07:00
init mm, memory_hotplug: drop zone from build_all_zonelists 2017-09-06 17:27:25 -07:00
ipc
kernel Device properties framework updates for v4.14-rc1 2017-09-05 12:50:00 -07:00
lib Driver core update for 4.14-rc1 2017-09-05 10:41:21 -07:00
mm mm: implement find_get_pages_range() 2017-09-06 17:27:26 -07:00
net Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid 2017-09-05 11:54:41 -07:00
samples
scripts modpost: simplify sec_name() 2017-09-06 17:27:24 -07:00
security
sound Merge branch 'parisc-4.14-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux 2017-09-05 09:37:11 -07:00
tools ACPI updates for v4.14-rc1 2017-09-05 12:45:03 -07:00
usr
virt
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS ACPI updates for v4.14-rc1 2017-09-05 12:45:03 -07:00
Makefile Merge branch 'docs-next' of git://git.lwn.net/linux 2017-09-03 21:07:29 -07:00
README

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

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

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.