From: "Theodore Y. Ts'o" <tytso@mit.edu>
To: Andreas Dilger <adilger@whamcloud.com>
Cc: linux-ext4@vger.kernel.org
Subject: Re: [PATCH 4/9] e2fsck: reduce memory usage for many directories
Date: Sat, 29 Feb 2020 18:29:14 -0500 [thread overview]
Message-ID: <20200229232914.GD38945@mit.edu> (raw)
In-Reply-To: <1581037786-62789-4-git-send-email-adilger@whamcloud.com>
On Thu, Feb 06, 2020 at 06:09:41PM -0700, Andreas Dilger wrote:
> Pack struct dx_dir_info and dx_dirblock_info properly in memory, to
> avoid holes, and fields are not larger than necessary. This reduces
> the memory needed for each hashed dir, according to pahole(1) from:
>
> struct dx_dir_info {
> /* size: 32, cachelines: 1, members: 6 */
> /* sum members: 26, holes: 1, sum holes: 2 */
> /* padding: 4 */
> };
> struct dx_dirblock_info {
> /* size: 56, cachelines: 1, members: 9 */
> /* sum members: 48, holes: 2, sum holes: 8 */
> /* last cacheline: 56 bytes */
> };
>
> to 8 bytes less for each directory and directory block, and leaves
> space for future use if needed (e.g. larger numblocks):
>
> struct dx_dir_info {
> /* size: 24, cachelines: 1, members: 6 */
> /* sum members: 20, holes: 1, sum holes: 4 */
> /* bit holes: 1, sum bit holes: 7 bits */
> };
> struct dx_dirblock_info {
> /* size: 48, cachelines: 1, members: 9 */
> };
>
> Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
> Lustre-bug-id: https://jira.whamcloud.com/browse/LU-13197
Applied, thanks.
- Ted
next prev parent reply other threads:[~2020-02-29 23:29 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-07 1:09 [PATCH 1/9] e2fsck: fix e2fsck_allocate_memory() overflow Andreas Dilger
2020-02-07 1:09 ` [PATCH 2/9] e2fsck: use proper types for variables Andreas Dilger
2020-02-29 23:27 ` Theodore Y. Ts'o
2020-02-07 1:09 ` [PATCH 3/9] e2fsck: avoid mallinfo() if over 2GB allocated Andreas Dilger
2020-02-29 23:28 ` Theodore Y. Ts'o
2020-02-07 1:09 ` [PATCH 4/9] e2fsck: reduce memory usage for many directories Andreas Dilger
2020-02-29 23:29 ` Theodore Y. Ts'o [this message]
2020-02-07 1:09 ` [PATCH 5/9] debugfs: allow comment lines in command file Andreas Dilger
2020-02-29 23:32 ` Theodore Y. Ts'o
2020-02-07 1:09 ` [PATCH 6/9] debugfs: print inode numbers as unsigned Andreas Dilger
2020-02-29 23:34 ` Theodore Y. Ts'o
2020-02-07 1:09 ` [PATCH 7/9] e2fsck: fix overflow if more than 4B inodes Andreas Dilger
2020-02-29 23:35 ` Theodore Y. Ts'o
2020-02-07 1:09 ` [PATCH 8/9] e2fsck: consistently use ext2fs_get_mem() Andreas Dilger
2020-02-29 23:36 ` Theodore Y. Ts'o
2020-03-04 23:23 ` Theodore Y. Ts'o
2020-02-07 1:09 ` [PATCH 9/9] misc: handle very large files with filefrag Andreas Dilger
2020-03-04 23:27 ` Theodore Y. Ts'o
2020-02-12 0:58 ` [PATCH] " Andreas Dilger
2020-02-12 1:09 ` Andreas Dilger
2020-02-12 1:07 ` [PATCH] e2fsck: avoid overflow with very large dirs Andreas Dilger
2020-03-04 23:39 ` Theodore Y. Ts'o
2020-02-29 23:25 ` [PATCH 1/9] e2fsck: fix e2fsck_allocate_memory() overflow Theodore Y. Ts'o
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