From: Wang Shilong <wshilong@xxxxxxx>
number of threads in pfsck should not exceed flex bg numbers.
This patch adds the support in libext2fs to calculate
ext2fs_get_avg_group() which returns an average group
count which each thread has to scan.
fs->fs_num_threads will be set by the client, in this case e2fsck.
No. of threads will be passed along with -m option while running e2fsck.
That will also set fs->fs_num_threads, which will help in controlling
the amount of memory consumed to maintain in memory data structures (per
thread) in case of multiple parallel threads (pfsck) to avoid oom.
Signed-off-by: Wang Shilong <wshilong@xxxxxxx>
Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@xxxxxxxxx>
---
lib/ext2fs/ext2fs.h | 32 +++++++++++++++++++++++++++++++-
1 file changed, 31 insertions(+), 1 deletion(-)
diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
index b1505f95..6b4926ce 100644
--- a/lib/ext2fs/ext2fs.h
+++ b/lib/ext2fs/ext2fs.h
@@ -279,10 +279,11 @@ struct struct_ext2_filsys {
int cluster_ratio_bits;
__u16 default_bitmap_type;
__u16 pad;
+ __u32 fs_num_threads;
/*
* Reserved for future expansion
*/
- __u32 reserved[5];
+ __u32 reserved[4];
/*
* Reserved for the use of the calling application.
@@ -2231,6 +2232,35 @@ ext2fs_orphan_block_tail(ext2_filsys fs, char *buf)
sizeof(struct ext4_orphan_block_tail));
}
+static dgrp_t ext2fs_get_avg_group(ext2_filsys fs)
+{
+#ifdef HAVE_PTHREAD
+ dgrp_t average_group;
+ unsigned flexbg_size;
+
+ if (fs->fs_num_threads <= 1)
+ return fs->group_desc_count;
+
+ average_group = fs->group_desc_count / fs->fs_num_threads;
+ if (average_group <= 1)
+ return 1;
+
+ if (ext2fs_has_feature_flex_bg(fs->super)) {
+ int times = 1;
+
+ flexbg_size = 1 << fs->super->s_log_groups_per_flex;
+ if (average_group % flexbg_size) {
+ times = average_group / flexbg_size;
+ average_group = times * flexbg_size;
+ }
+ }
+
+ return average_group;
+#else
+ return fs->group_desc_count;
+#endif
+}
+
#undef _INLINE_
#endif
--
2.37.3
