From: Jan Kara <jack@suse.cz>
To: linux-ext4@vger.kernel.org
Cc: Ted Tso <tytso@mit.edu>, Jan Kara <jack@suse.cz>
Subject: [PATCH 0/5] jbd2: Avoid unnecessary locking when buffer is already journaled
Date: Thu, 2 Apr 2015 15:58:15 +0200 [thread overview]
Message-ID: <1427983100-29889-1-git-send-email-jack@suse.cz> (raw)
Hello,
this patch set improves do_get_write_access(), jbd2_journal_get_undo_access(),
and jbd2_journal_dirty_metadata() to be completely lockless in case buffer
is already part of an appropriate journalling list. First three patches
are independent small cleanups so they can go in right away I think.
The other two patches *should* improve the situation for frequent bitmap
or inode table block updates. But frankly, I haven't been able to come up
with a load where I'd see significant contention on update of a single buffer
(or it's hidden by a larger lock). Similarly we could see improvements when
do_get_write_access() would be waiting for buffer lock because buffer is
being written out by checkpointing code. But again I wasn't able to hit this
reliably.
Ted, you mentioned at Vault you had a setup where frequent
do_get_write_access() calls were contending in the revoke code. What was the
load exactly? These patches should improve that as well...
Honza
next reply other threads:[~2015-04-02 13:58 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-02 13:58 Jan Kara [this message]
2015-04-02 13:58 ` [PATCH 1/5] jbd2: Simplify code flow in do_get_write_access() Jan Kara
2015-06-08 16:39 ` Theodore Ts'o
2015-04-02 13:58 ` [PATCH 2/5] jbd2: Simplify error path on allocation failure " Jan Kara
2015-06-08 16:42 ` Theodore Ts'o
2015-04-02 13:58 ` [PATCH 3/5] jbd2: Simplify code flow " Jan Kara
2015-06-08 16:45 ` Theodore Ts'o
2015-04-02 13:58 ` [PATCH 4/5] jbd2: Speedup jbd2_journal_get_[write|undo]_access() Jan Kara
2015-06-08 16:47 ` Theodore Ts'o
2015-06-08 22:32 ` Theodore Ts'o
2015-06-09 5:24 ` Theodore Ts'o
2015-06-17 16:39 ` Jan Kara
2015-06-17 16:56 ` Jan Kara
[not found] ` <CAA1ppbhojR0aaDr-BUWQLWQDo5+sO9Tc6b=Dxf5XrRAr2DT0oQ@mail.gmail.com>
2015-06-18 8:52 ` Jan Kara
2015-06-21 1:56 ` Theodore Ts'o
2015-04-02 13:58 ` [PATCH 5/5] jbd2: Speedup jbd2_journal_dirty_metadata() Jan Kara
2015-06-08 16:50 ` Theodore Ts'o
2015-04-02 14:23 ` [PATCH 0/5] jbd2: Avoid unnecessary locking when buffer is already journaled Theodore Ts'o
2015-04-12 10:09 ` Dmitry Monakhov
2015-04-16 10:46 ` Jan Kara
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