From a9cc799eca0c798ab5dd8648564fc2025bdd9bd2 Mon Sep 17 00:00:00 2001 From: Eric Sandeen Date: Wed, 3 Feb 2010 17:50:13 +0000 Subject: [PATCH] xfs: increase readdir buffer size While doing some testing of readdir perf a while back, I noticed that the buffer size we're using internally is smaller than what glibc gives us by default. Upping this size helped a bit, and seems safe. glibc's __alloc_dir() does: const size_t default_allocation = (4 * BUFSIZ < sizeof (struct dirent64) ? sizeof (struct dirent64) : 4 * BUFSIZ); const size_t small_allocation = (BUFSIZ < sizeof (struct dirent64) ? sizeof (struct dirent64) : BUFSIZ); size_t allocation = default_allocation; #ifdef _STATBUF_ST_BLKSIZE if (statp != NULL && default_allocation < statp->st_blksize) allocation = statp->st_blksize; #endif and #define _G_BUFSIZ 8192 #define _IO_BUFSIZ _G_BUFSIZ # define BUFSIZ _IO_BUFSIZ so the default buffer is 4 * 8192 = 32768 (except in the unlikely case of blocks > 32k....) Signed-off-by: Eric Sandeen Reviewed-by: Christoph Hellwig Signed-off-by: Alex Elder --- fs/xfs/linux-2.6/xfs_file.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/xfs/linux-2.6/xfs_file.c b/fs/xfs/linux-2.6/xfs_file.c index e4caeb28ce2e..3805ada98747 100644 --- a/fs/xfs/linux-2.6/xfs_file.c +++ b/fs/xfs/linux-2.6/xfs_file.c @@ -203,9 +203,9 @@ xfs_file_readdir( * * Try to give it an estimate that's good enough, maybe at some * point we can change the ->readdir prototype to include the - * buffer size. + * buffer size. For now we use the current glibc buffer size. */ - bufsize = (size_t)min_t(loff_t, PAGE_SIZE, ip->i_d.di_size); + bufsize = (size_t)min_t(loff_t, 32768, ip->i_d.di_size); error = xfs_readdir(ip, dirent, bufsize, (xfs_off_t *)&filp->f_pos, filldir); -- GitLab