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f3650ef89b
Patch series "Improve the tmpfs large folio read performance", v2. tmpfs already supports PMD-sized large folios, but the tmpfs read operation still performs copying at PAGE_SIZE granularity, which is not perfect. This patchset changes tmpfs to copy data at the folio granularity, which can improve the read performance. Use 'fio bs=64k' to read a 1G tmpfs file populated with 2M THPs, and I can see about 20% performance improvement, and no regression with bs=4k. I also did some functional testing with the xfstests suite, and I did not find any regressions with the following xfstests config: FSTYP=tmpfs export TEST_DIR=/mnt/tempfs_mnt export TEST_DEV=/mnt/tempfs_mnt export SCRATCH_MNT=/mnt/scratchdir export SCRATCH_DEV=/mnt/scratchdir This patch (of 2): Using iocb->ki_pos to check if the read bytes exceeds the file size and to calculate the bytes to be read can help simplify the code logic. Meanwhile, this is also a preparation for improving tmpfs large folios read performance in the following patch. Link: https://lkml.kernel.org/r/cover.1729218573.git.baolin.wang@linux.alibaba.com Link: https://lkml.kernel.org/r/e8863e289577e0dc1e365b5419bf2d1c9a24ae3d.1729218573.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Yang Shi <shy828301@gmail.com> Cc: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Matthew Wilcox <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.