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  1. Lustre
  2. LU-17779

switch lnet loopback to use copy_page()

Details

    • Improvement
    • Resolution: Fixed
    • Minor
    • Lustre 2.16.0
    • None
    • None
    • 3
    • 9223372036854775807

    Description

      When copying one page to another in kernel memory (not to/from userspace, so this can't be used for the general purpose IO stuff), the kernel has an optimized copy_page which can be used instead of memcpy().

      This is relevant in the lnet loopback subsystem, which copies from the kiov from the client to that on the server.  (Using the same page is nasty for a lot of reasons, so copying is best.)  The most common case is full page to full page, so add a check for that.

      On my little tiny VM system, this improves maximum write performance (with the fake write fail_loc enabled) by about 20%, from 4.4 GiB/s to 5.7 GiB/s.

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            [LU-17779] switch lnet loopback to use copy_page()

            "Oleg Drokin <green@whamcloud.com>" merged in patch https://review.whamcloud.com/c/fs/lustre-release/+/54923/
            Subject: LU-17779 lnet: use copy_page()
            Project: fs/lustre-release
            Branch: master
            Current Patch Set:
            Commit: 36629c15fbd0e2d88e813f4d8af392b71da8147d

            gerrit Gerrit Updater added a comment - "Oleg Drokin <green@whamcloud.com>" merged in patch https://review.whamcloud.com/c/fs/lustre-release/+/54923/ Subject: LU-17779 lnet: use copy_page() Project: fs/lustre-release Branch: master Current Patch Set: Commit: 36629c15fbd0e2d88e813f4d8af392b71da8147d

            "Patrick Farrell <patrick.farrell@oracle.com>" uploaded a new patch: https://review.whamcloud.com/c/fs/lustre-release/+/54923
            Subject: LU-17779 lnet: use copy_page()
            Project: fs/lustre-release
            Branch: master
            Current Patch Set: 1
            Commit: 91f3dfb7fda00e2c0dbcceb17a1e51b22349152e

            gerrit Gerrit Updater added a comment - "Patrick Farrell <patrick.farrell@oracle.com>" uploaded a new patch: https://review.whamcloud.com/c/fs/lustre-release/+/54923 Subject: LU-17779 lnet: use copy_page() Project: fs/lustre-release Branch: master Current Patch Set: 1 Commit: 91f3dfb7fda00e2c0dbcceb17a1e51b22349152e

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              paf Patrick Farrell (Inactive)
              paf Patrick Farrell (Inactive)
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                Updated:
                Resolved: