From: Christian Brauner <brauner@kernel.org>
Date: Thu, 21 Nov 2024 10:15:21 +0000 (+0100)
Subject: Merge patch series "symlink length caching"
X-Git-Tag: v6.14-rc1~216^2~14
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=84208b8fa3b7e73d1cc08efe7eaf527e28d8b951;p=thirdparty%2Fkernel%2Flinux.git

Merge patch series "symlink length caching"

Mateusz Guzik <mjguzik@gmail.com> says:

quote:
    When utilized it dodges strlen() in vfs_readlink(), giving about 1.5%
    speed up when issuing readlink on /initrd.img on ext4.

The size is stored in a union with i_devices, which is never looked at
unless the inode is for a device.

ext4 and tmpfs are patched, other filesystems can also get there with
some more work.

benchmark:
plug into will-it-scale into tests/readlink1.c:

char *testcase_description = "readlink /initrd.img";

void testcase(unsigned long long *iterations, unsigned long nr)
{
        char *tmplink = "/initrd.img";
        char buf[1024];

        while (1) {
                int error = readlink(tmplink, buf, sizeof(buf));
                assert(error > 0);

                (*iterations)++;
        }
}

* patches from https://lore.kernel.org/r/20241120112037.822078-1-mjguzik@gmail.com:
  tmpfs: use inode_set_cached_link()
  ext4: use inode_set_cached_link()
  vfs: support caching symlink lengths in inodes

Link: https://lore.kernel.org/r/20241120112037.822078-1-mjguzik@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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84208b8fa3b7e73d1cc08efe7eaf527e28d8b951