mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-05-14 10:02:33 -04:00
0faa77afe7
There are two meaningless folio refcount update for order0 folio in filemap_map_pages(). First, filemap_map_order0_folio() adds folio refcount after the folio is mapped to pte. And then, filemap_map_pages() drops a refcount grabbed by next_uptodate_folio(). We could remain the refcount unchanged in this case. As Matthew metenioned in [1], it is safe to call folio_unlock() before calling folio_put() here, because the folio is in page cache with refcount held, and truncation will wait for the unlock. Optimize filemap_map_folio_range() with the same method too. With this patch, we can get 8% performance gain for lmbench testcase 'lat_pagefault -P 1 file' in order0 folio case, the size of file is 512M. Link: https://lkml.kernel.org/r/20250904132737.1250368-1-tujinjiang@huawei.com Link: https://lore.kernel.org/all/aKcU-fzxeW3xT5Wv@casper.infradead.org/ [1] Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.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 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.