Mike Snitzer
be04c14a1b
Split abnormal IO in terms of the corresponding operation specific max_sectors (max_discard_sectors, max_secure_erase_sectors or max_write_zeroes_sectors). This fixes a significant dm-thinp discard performance regression that was introduced with commite2dd8aca2d("dm bio prison v1: improve concurrent IO performance"). Relative to discard: max_discard_sectors is used instead of max_sectors; which fixes excessive discard splitting (e.g. max_sectors=128K vs max_discard_sectors=64M). Tested by discarding an 1 Petabyte dm-thin device: lvcreate -V 1125899906842624B -T test/pool -n thin time blkdiscard /dev/test/thin Before this fix (splitting discards every 128K): ~116m After this fix (splitting discards every 64M) : 0m33.460s Reported-by: Zorro Lang <zlang@redhat.com> Fixes:06961c487a("dm: split discards further if target sets max_discard_granularity") Requires:13f6facf3f("dm: allow targets to require splitting WRITE_ZEROES and SECURE_ERASE") Fixes:e2dd8aca2d("dm bio prison v1: improve concurrent IO performance") Signed-off-by: Mike Snitzer <snitzer@kernel.org>
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.