Matthew Wilcox (Oracle) 9cecde80aa mm: increase folio batch size
On a 104 thread, 2 socket Skylake system, Intel report a 4.7% performance
reduction with will-it-scale page_fault2.  This was due to reducing the
size of the batch from 32 to 15.  Increasing the folio batch size from 15
to 31 gives a performance increase of 12.5% relative to the original, or
17.2% relative to the reduced performance commit.

The penalty of this commit is an additional 128 bytes of stack usage.  Six
folio_batches are also allocated from percpu memory in cpu_fbatches so
that will be an additional 768 bytes of percpu memory (per CPU).  Tim Chen
originally submitted a patch like this in 2020:
https://lore.kernel.org/linux-mm/d1cc9f12a8ad6c2a52cb600d93b06b064f2bbc57.1593205965.git.tim.c.chen@linux.intel.com/

Link: https://lkml.kernel.org/r/20240315140823.2478146-1-willy@infradead.org
Fixes: 99fbb6bfc1 ("mm: make folios_put() the basis of release_pages()")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Tested-by: Yujie Liu <yujie.liu@intel.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202403151058.7048f6a8-oliver.sang@intel.com
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-03-26 11:07:20 -07:00
2024-03-26 11:07:20 -07:00
2024-03-26 11:07:20 -07:00
2024-03-24 14:10:05 -07:00
2024-03-18 03:36:32 -06:00

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 reStructuredText 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.
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