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Jan Kara
14ff628630
When reserved transaction handle is unused, we subtract its reserved
credits in __jbd2_journal_unreserve_handle() called from
jbd2_journal_stop(). However this function forgets to remove reserved
credits from transaction->t_outstanding_credits and thus the transaction
space that was reserved remains effectively leaked. The leaked
transaction space can be quite significant in some cases and leads to
unnecessarily small transactions and thus reducing throughput of the
journalling machinery. E.g. fsmark workload creating lots of 4k files
was observed to have about 20% lower throughput due to this when ext4 is
mounted with dioread_nolock mount option.
Subtract reserved credits from t_outstanding_credits as well.
CC: [email protected]
Fixes: 8f7d89f368 ("jbd2: transaction reservation support")
Reviewed-by: Andreas Dilger <[email protected]>
Signed-off-by: Jan Kara <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Theodore Ts'o <[email protected]>
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.