This is a note to let you know that I've just added the patch titled
ext4: add mballoc stats proc file
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ext4-add-mballoc-stats-proc-file.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 98f5eedb9fcc293187dbf950338190fbd7b97635
Author: Harshad Shirwadkar <harshadshirwadkar@xxxxxxxxx>
Date: Thu Apr 1 10:21:25 2021 -0700
ext4: add mballoc stats proc file
[ Upstream commit a6c75eaf11032f4a3d2b3ce2265a194ac6e4a7f0 ]
Add new stats for measuring the performance of mballoc. This patch is
forked from Artem Blagodarenko's work that can be found here:
https://github.com/lustre/lustre-release/blob/master/ldiskfs/kernel_patches/patches/rhel8/ext4-simple-blockalloc.patch
This patch reorganizes the stats by cr level. This is how the output
looks like:
mballoc:
reqs: 0
success: 0
groups_scanned: 0
cr0_stats:
hits: 0
groups_considered: 0
useless_loops: 0
bad_suggestions: 0
cr1_stats:
hits: 0
groups_considered: 0
useless_loops: 0
bad_suggestions: 0
cr2_stats:
hits: 0
groups_considered: 0
useless_loops: 0
cr3_stats:
hits: 0
groups_considered: 0
useless_loops: 0
extents_scanned: 0
goal_hits: 0
2^n_hits: 0
breaks: 0
lost: 0
buddies_generated: 0/40
buddies_time_used: 0
preallocated: 0
discarded: 0
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@xxxxxxxxx>
Reviewed-by: Andreas Dilger <adilger@xxxxxxxxx>
Reviewed-by: Ritesh Harjani <ritesh.list@xxxxxxxxx>
Link: https://lore.kernel.org/r/20210401172129.189766-4-harshadshirwadkar@xxxxxxxxx
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Stable-dep-of: 5354b2af3406 ("ext4: allow ext4_get_group_info() to fail")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 5efd48d7c9a79..1de55d8e0d354 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1535,9 +1535,13 @@ struct ext4_sb_info {
atomic_t s_bal_success; /* we found long enough chunks */
atomic_t s_bal_allocated; /* in blocks */
atomic_t s_bal_ex_scanned; /* total extents scanned */
+ atomic_t s_bal_groups_scanned; /* number of groups scanned */
atomic_t s_bal_goals; /* goal hits */
atomic_t s_bal_breaks; /* too long searches */
atomic_t s_bal_2orders; /* 2^order hits */
+ atomic64_t s_bal_cX_groups_considered[4];
+ atomic64_t s_bal_cX_hits[4];
+ atomic64_t s_bal_cX_failed[4]; /* cX loop didn't find blocks */
atomic_t s_mb_buddies_generated; /* number of buddies generated */
atomic64_t s_mb_generation_time;
atomic_t s_mb_lost_chunks;
@@ -2784,6 +2788,7 @@ int ext4_fc_record_regions(struct super_block *sb, int ino,
extern const struct seq_operations ext4_mb_seq_groups_ops;
extern long ext4_mb_stats;
extern long ext4_mb_max_to_scan;
+extern int ext4_seq_mb_stats_show(struct seq_file *seq, void *offset);
extern int ext4_mb_init(struct super_block *);
extern int ext4_mb_release(struct super_block *);
extern ext4_fsblk_t ext4_mb_new_blocks(handle_t *,
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index beee54480562a..aa51d1b837274 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2151,6 +2151,8 @@ static int ext4_mb_good_group_nolock(struct ext4_allocation_context *ac,
ext4_grpblk_t free;
int ret = 0;
+ if (sbi->s_mb_stats)
+ atomic64_inc(&sbi->s_bal_cX_groups_considered[ac->ac_criteria]);
if (should_lock)
ext4_lock_group(sb, group);
free = grp->bb_free;
@@ -2425,6 +2427,9 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
if (ac->ac_status != AC_STATUS_CONTINUE)
break;
}
+ /* Processed all groups and haven't found blocks */
+ if (sbi->s_mb_stats && i == ngroups)
+ atomic64_inc(&sbi->s_bal_cX_failed[cr]);
}
if (ac->ac_b_ex.fe_len > 0 && ac->ac_status != AC_STATUS_FOUND &&
@@ -2454,6 +2459,9 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
goto repeat;
}
}
+
+ if (sbi->s_mb_stats && ac->ac_status == AC_STATUS_FOUND)
+ atomic64_inc(&sbi->s_bal_cX_hits[ac->ac_criteria]);
out:
if (!err && ac->ac_status != AC_STATUS_FOUND && first_err)
err = first_err;
@@ -2553,6 +2561,67 @@ const struct seq_operations ext4_mb_seq_groups_ops = {
.show = ext4_mb_seq_groups_show,
};
+int ext4_seq_mb_stats_show(struct seq_file *seq, void *offset)
+{
+ struct super_block *sb = (struct super_block *)seq->private;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+ seq_puts(seq, "mballoc:\n");
+ if (!sbi->s_mb_stats) {
+ seq_puts(seq, "\tmb stats collection turned off.\n");
+ seq_puts(seq, "\tTo enable, please write \"1\" to sysfs file mb_stats.\n");
+ return 0;
+ }
+ seq_printf(seq, "\treqs: %u\n", atomic_read(&sbi->s_bal_reqs));
+ seq_printf(seq, "\tsuccess: %u\n", atomic_read(&sbi->s_bal_success));
+
+ seq_printf(seq, "\tgroups_scanned: %u\n", atomic_read(&sbi->s_bal_groups_scanned));
+
+ seq_puts(seq, "\tcr0_stats:\n");
+ seq_printf(seq, "\t\thits: %llu\n", atomic64_read(&sbi->s_bal_cX_hits[0]));
+ seq_printf(seq, "\t\tgroups_considered: %llu\n",
+ atomic64_read(&sbi->s_bal_cX_groups_considered[0]));
+ seq_printf(seq, "\t\tuseless_loops: %llu\n",
+ atomic64_read(&sbi->s_bal_cX_failed[0]));
+
+ seq_puts(seq, "\tcr1_stats:\n");
+ seq_printf(seq, "\t\thits: %llu\n", atomic64_read(&sbi->s_bal_cX_hits[1]));
+ seq_printf(seq, "\t\tgroups_considered: %llu\n",
+ atomic64_read(&sbi->s_bal_cX_groups_considered[1]));
+ seq_printf(seq, "\t\tuseless_loops: %llu\n",
+ atomic64_read(&sbi->s_bal_cX_failed[1]));
+
+ seq_puts(seq, "\tcr2_stats:\n");
+ seq_printf(seq, "\t\thits: %llu\n", atomic64_read(&sbi->s_bal_cX_hits[2]));
+ seq_printf(seq, "\t\tgroups_considered: %llu\n",
+ atomic64_read(&sbi->s_bal_cX_groups_considered[2]));
+ seq_printf(seq, "\t\tuseless_loops: %llu\n",
+ atomic64_read(&sbi->s_bal_cX_failed[2]));
+
+ seq_puts(seq, "\tcr3_stats:\n");
+ seq_printf(seq, "\t\thits: %llu\n", atomic64_read(&sbi->s_bal_cX_hits[3]));
+ seq_printf(seq, "\t\tgroups_considered: %llu\n",
+ atomic64_read(&sbi->s_bal_cX_groups_considered[3]));
+ seq_printf(seq, "\t\tuseless_loops: %llu\n",
+ atomic64_read(&sbi->s_bal_cX_failed[3]));
+ seq_printf(seq, "\textents_scanned: %u\n", atomic_read(&sbi->s_bal_ex_scanned));
+ seq_printf(seq, "\t\tgoal_hits: %u\n", atomic_read(&sbi->s_bal_goals));
+ seq_printf(seq, "\t\t2^n_hits: %u\n", atomic_read(&sbi->s_bal_2orders));
+ seq_printf(seq, "\t\tbreaks: %u\n", atomic_read(&sbi->s_bal_breaks));
+ seq_printf(seq, "\t\tlost: %u\n", atomic_read(&sbi->s_mb_lost_chunks));
+
+ seq_printf(seq, "\tbuddies_generated: %u/%u\n",
+ atomic_read(&sbi->s_mb_buddies_generated),
+ ext4_get_groups_count(sb));
+ seq_printf(seq, "\tbuddies_time_used: %llu\n",
+ atomic64_read(&sbi->s_mb_generation_time));
+ seq_printf(seq, "\tpreallocated: %u\n",
+ atomic_read(&sbi->s_mb_preallocated));
+ seq_printf(seq, "\tdiscarded: %u\n",
+ atomic_read(&sbi->s_mb_discarded));
+ return 0;
+}
+
static struct kmem_cache *get_groupinfo_cache(int blocksize_bits)
{
int cache_index = blocksize_bits - EXT4_MIN_BLOCK_LOG_SIZE;
@@ -2980,9 +3049,10 @@ int ext4_mb_release(struct super_block *sb)
atomic_read(&sbi->s_bal_reqs),
atomic_read(&sbi->s_bal_success));
ext4_msg(sb, KERN_INFO,
- "mballoc: %u extents scanned, %u goal hits, "
+ "mballoc: %u extents scanned, %u groups scanned, %u goal hits, "
"%u 2^N hits, %u breaks, %u lost",
atomic_read(&sbi->s_bal_ex_scanned),
+ atomic_read(&sbi->s_bal_groups_scanned),
atomic_read(&sbi->s_bal_goals),
atomic_read(&sbi->s_bal_2orders),
atomic_read(&sbi->s_bal_breaks),
@@ -3620,12 +3690,13 @@ static void ext4_mb_collect_stats(struct ext4_allocation_context *ac)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
- if (sbi->s_mb_stats && ac->ac_g_ex.fe_len > 1) {
+ if (sbi->s_mb_stats && ac->ac_g_ex.fe_len >= 1) {
atomic_inc(&sbi->s_bal_reqs);
atomic_add(ac->ac_b_ex.fe_len, &sbi->s_bal_allocated);
if (ac->ac_b_ex.fe_len >= ac->ac_o_ex.fe_len)
atomic_inc(&sbi->s_bal_success);
atomic_add(ac->ac_found, &sbi->s_bal_ex_scanned);
+ atomic_add(ac->ac_groups_scanned, &sbi->s_bal_groups_scanned);
if (ac->ac_g_ex.fe_start == ac->ac_b_ex.fe_start &&
ac->ac_g_ex.fe_group == ac->ac_b_ex.fe_group)
atomic_inc(&sbi->s_bal_goals);
diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c
index ce74cde6d8faa..b0bb4a92c9c94 100644
--- a/fs/ext4/sysfs.c
+++ b/fs/ext4/sysfs.c
@@ -539,6 +539,8 @@ int ext4_register_sysfs(struct super_block *sb)
ext4_fc_info_show, sb);
proc_create_seq_data("mb_groups", S_IRUGO, sbi->s_proc,
&ext4_mb_seq_groups_ops, sb);
+ proc_create_single_data("mb_stats", 0444, sbi->s_proc,
+ ext4_seq_mb_stats_show, sb);
}
return 0;
}
