22c06bf1f9
commit 869b6ea1609f655a43251bf41757aa44e5350a8f upstream.
Eric has reported that commit dabc8b207566 ("quota: fix dqput() to
follow the guarantees dquot_srcu should provide") heavily increases
runtime of generic/270 xfstest for ext4 in nojournal mode. The reason
for this is that ext4 in nojournal mode leaves dquots dirty until the last
dqput() and thus the cleanup done in quota_release_workfn() has to write
them all. Due to the way quota_release_workfn() is written this results
in synchronize_srcu() call for each dirty dquot which makes the dquot
cleanup when turning quotas off extremely slow.
To be able to avoid synchronize_srcu() for each dirty dquot we need to
rework how we track dquots to be cleaned up. Instead of keeping the last
dquot reference while it is on releasing_dquots list, we drop it right
away and mark the dquot with new DQ_RELEASING_B bit instead. This way we
can we can remove dquot from releasing_dquots list when new reference to
it is acquired and thus there's no need to call synchronize_srcu() each
time we drop dq_list_lock.
References: https://lore.kernel.org/all/ZRytn6CxFK2oECUt@debian-BULLSEYE-live-builder-AMD64
Reported-by: Eric Whitney <enwlinux@gmail.com>
Fixes: dabc8b207566 ("quota: fix dqput() to follow the guarantees dquot_srcu should provide")
CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| 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.