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authorDaeho Jeong <daehojeong@google.com>2021-09-29 21:12:03 +0300
committerJaegeuk Kim <jaegeuk@kernel.org>2021-10-27 00:04:30 +0300
commit6691d940b0e09dd1564130e7a354d6deaf05d009 (patch)
treeae609ea58abdfd7ce7c73e72f82d39226f2de3a9 /fs/f2fs/sysfs.c
parent84eab2a899f28137e51a36861ed2df9579f54ebe (diff)
downloadlinux-6691d940b0e09dd1564130e7a354d6deaf05d009.tar.xz
f2fs: introduce fragment allocation mode mount option
Added two options into "mode=" mount option to make it possible for developers to simulate filesystem fragmentation/after-GC situation itself. The developers use these modes to understand filesystem fragmentation/after-GC condition well, and eventually get some insights to handle them better. "fragment:segment": f2fs allocates a new segment in ramdom position. With this, we can simulate the after-GC condition. "fragment:block" : We can scatter block allocation with "max_fragment_chunk" and "max_fragment_hole" sysfs nodes. f2fs will allocate 1..<max_fragment_chunk> blocks in a chunk and make a hole in the length of 1..<max_fragment_hole> by turns in a newly allocated free segment. Plus, this mode implicitly enables "fragment:segment" option for more randomness. Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Daeho Jeong <daehojeong@google.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Diffstat (limited to 'fs/f2fs/sysfs.c')
-rw-r--r--fs/f2fs/sysfs.c20
1 files changed, 20 insertions, 0 deletions
diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index 0fb891efdead..7d289249cd7e 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -551,6 +551,22 @@ out:
return count;
}
+ if (!strcmp(a->attr.name, "max_fragment_chunk")) {
+ if (t >= MIN_FRAGMENT_SIZE && t <= MAX_FRAGMENT_SIZE)
+ sbi->max_fragment_chunk = t;
+ else
+ return -EINVAL;
+ return count;
+ }
+
+ if (!strcmp(a->attr.name, "max_fragment_hole")) {
+ if (t >= MIN_FRAGMENT_SIZE && t <= MAX_FRAGMENT_SIZE)
+ sbi->max_fragment_hole = t;
+ else
+ return -EINVAL;
+ return count;
+ }
+
*ui = (unsigned int)t;
return count;
@@ -781,6 +797,8 @@ F2FS_RW_ATTR(ATGC_INFO, atgc_management, atgc_age_threshold, age_threshold);
F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, seq_file_ra_mul, seq_file_ra_mul);
F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, gc_segment_mode, gc_segment_mode);
F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, gc_reclaimed_segments, gc_reclaimed_segs);
+F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, max_fragment_chunk, max_fragment_chunk);
+F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, max_fragment_hole, max_fragment_hole);
#define ATTR_LIST(name) (&f2fs_attr_##name.attr)
static struct attribute *f2fs_attrs[] = {
@@ -859,6 +877,8 @@ static struct attribute *f2fs_attrs[] = {
ATTR_LIST(seq_file_ra_mul),
ATTR_LIST(gc_segment_mode),
ATTR_LIST(gc_reclaimed_segments),
+ ATTR_LIST(max_fragment_chunk),
+ ATTR_LIST(max_fragment_hole),
NULL,
};
ATTRIBUTE_GROUPS(f2fs);