ext4: Use tracepoints for mb_history trace file
The /proc/fs/ext4/<dev>/mb_history was maintained manually, and had a
number of problems: it required a largish amount of memory to be
allocated for each ext4 filesystem, and the s_mb_history_lock
introduced a CPU contention problem.
By ripping out the mb_history code and replacing it with ftrace
tracepoints, and we get more functionality: timestamps, event
filtering, the ability to correlate mballoc history with other ext4
tracepoints, etc.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 3e2320e..bba1282 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2096,207 +2096,6 @@
return err;
}
-#ifdef EXT4_MB_HISTORY
-struct ext4_mb_proc_session {
- struct ext4_mb_history *history;
- struct super_block *sb;
- int start;
- int max;
-};
-
-static void *ext4_mb_history_skip_empty(struct ext4_mb_proc_session *s,
- struct ext4_mb_history *hs,
- int first)
-{
- if (hs == s->history + s->max)
- hs = s->history;
- if (!first && hs == s->history + s->start)
- return NULL;
- while (hs->orig.fe_len == 0) {
- hs++;
- if (hs == s->history + s->max)
- hs = s->history;
- if (hs == s->history + s->start)
- return NULL;
- }
- return hs;
-}
-
-static void *ext4_mb_seq_history_start(struct seq_file *seq, loff_t *pos)
-{
- struct ext4_mb_proc_session *s = seq->private;
- struct ext4_mb_history *hs;
- int l = *pos;
-
- if (l == 0)
- return SEQ_START_TOKEN;
- hs = ext4_mb_history_skip_empty(s, s->history + s->start, 1);
- if (!hs)
- return NULL;
- while (--l && (hs = ext4_mb_history_skip_empty(s, ++hs, 0)) != NULL);
- return hs;
-}
-
-static void *ext4_mb_seq_history_next(struct seq_file *seq, void *v,
- loff_t *pos)
-{
- struct ext4_mb_proc_session *s = seq->private;
- struct ext4_mb_history *hs = v;
-
- ++*pos;
- if (v == SEQ_START_TOKEN)
- return ext4_mb_history_skip_empty(s, s->history + s->start, 1);
- else
- return ext4_mb_history_skip_empty(s, ++hs, 0);
-}
-
-static int ext4_mb_seq_history_show(struct seq_file *seq, void *v)
-{
- char buf[25], buf2[25], buf3[25], *fmt;
- struct ext4_mb_history *hs = v;
-
- if (v == SEQ_START_TOKEN) {
- seq_printf(seq, "%-5s %-8s %-23s %-23s %-23s %-5s "
- "%-5s %-2s %-6s %-5s %-5s %-6s\n",
- "pid", "inode", "original", "goal", "result", "found",
- "grps", "cr", "flags", "merge", "tail", "broken");
- return 0;
- }
-
- if (hs->op == EXT4_MB_HISTORY_ALLOC) {
- fmt = "%-5u %-8u %-23s %-23s %-23s %-5u %-5u %-2u "
- "0x%04x %-5s %-5u %-6u\n";
- sprintf(buf2, "%u/%d/%u@%u", hs->result.fe_group,
- hs->result.fe_start, hs->result.fe_len,
- hs->result.fe_logical);
- sprintf(buf, "%u/%d/%u@%u", hs->orig.fe_group,
- hs->orig.fe_start, hs->orig.fe_len,
- hs->orig.fe_logical);
- sprintf(buf3, "%u/%d/%u@%u", hs->goal.fe_group,
- hs->goal.fe_start, hs->goal.fe_len,
- hs->goal.fe_logical);
- seq_printf(seq, fmt, hs->pid, hs->ino, buf, buf3, buf2,
- hs->found, hs->groups, hs->cr, hs->flags,
- hs->merged ? "M" : "", hs->tail,
- hs->buddy ? 1 << hs->buddy : 0);
- } else if (hs->op == EXT4_MB_HISTORY_PREALLOC) {
- fmt = "%-5u %-8u %-23s %-23s %-23s\n";
- sprintf(buf2, "%u/%d/%u@%u", hs->result.fe_group,
- hs->result.fe_start, hs->result.fe_len,
- hs->result.fe_logical);
- sprintf(buf, "%u/%d/%u@%u", hs->orig.fe_group,
- hs->orig.fe_start, hs->orig.fe_len,
- hs->orig.fe_logical);
- seq_printf(seq, fmt, hs->pid, hs->ino, buf, "", buf2);
- } else if (hs->op == EXT4_MB_HISTORY_DISCARD) {
- sprintf(buf2, "%u/%d/%u", hs->result.fe_group,
- hs->result.fe_start, hs->result.fe_len);
- seq_printf(seq, "%-5u %-8u %-23s discard\n",
- hs->pid, hs->ino, buf2);
- } else if (hs->op == EXT4_MB_HISTORY_FREE) {
- sprintf(buf2, "%u/%d/%u", hs->result.fe_group,
- hs->result.fe_start, hs->result.fe_len);
- seq_printf(seq, "%-5u %-8u %-23s free\n",
- hs->pid, hs->ino, buf2);
- }
- return 0;
-}
-
-static void ext4_mb_seq_history_stop(struct seq_file *seq, void *v)
-{
-}
-
-static const struct seq_operations ext4_mb_seq_history_ops = {
- .start = ext4_mb_seq_history_start,
- .next = ext4_mb_seq_history_next,
- .stop = ext4_mb_seq_history_stop,
- .show = ext4_mb_seq_history_show,
-};
-
-static int ext4_mb_seq_history_open(struct inode *inode, struct file *file)
-{
- struct super_block *sb = PDE(inode)->data;
- struct ext4_sb_info *sbi = EXT4_SB(sb);
- struct ext4_mb_proc_session *s;
- int rc;
- int size;
-
- if (unlikely(sbi->s_mb_history == NULL))
- return -ENOMEM;
- s = kmalloc(sizeof(*s), GFP_KERNEL);
- if (s == NULL)
- return -ENOMEM;
- s->sb = sb;
- size = sizeof(struct ext4_mb_history) * sbi->s_mb_history_max;
- s->history = kmalloc(size, GFP_KERNEL);
- if (s->history == NULL) {
- kfree(s);
- return -ENOMEM;
- }
-
- spin_lock(&sbi->s_mb_history_lock);
- memcpy(s->history, sbi->s_mb_history, size);
- s->max = sbi->s_mb_history_max;
- s->start = sbi->s_mb_history_cur % s->max;
- spin_unlock(&sbi->s_mb_history_lock);
-
- rc = seq_open(file, &ext4_mb_seq_history_ops);
- if (rc == 0) {
- struct seq_file *m = (struct seq_file *)file->private_data;
- m->private = s;
- } else {
- kfree(s->history);
- kfree(s);
- }
- return rc;
-
-}
-
-static int ext4_mb_seq_history_release(struct inode *inode, struct file *file)
-{
- struct seq_file *seq = (struct seq_file *)file->private_data;
- struct ext4_mb_proc_session *s = seq->private;
- kfree(s->history);
- kfree(s);
- return seq_release(inode, file);
-}
-
-static ssize_t ext4_mb_seq_history_write(struct file *file,
- const char __user *buffer,
- size_t count, loff_t *ppos)
-{
- struct seq_file *seq = (struct seq_file *)file->private_data;
- struct ext4_mb_proc_session *s = seq->private;
- struct super_block *sb = s->sb;
- char str[32];
- int value;
-
- if (count >= sizeof(str)) {
- printk(KERN_ERR "EXT4-fs: %s string too long, max %u bytes\n",
- "mb_history", (int)sizeof(str));
- return -EOVERFLOW;
- }
-
- if (copy_from_user(str, buffer, count))
- return -EFAULT;
-
- value = simple_strtol(str, NULL, 0);
- if (value < 0)
- return -ERANGE;
- EXT4_SB(sb)->s_mb_history_filter = value;
-
- return count;
-}
-
-static const struct file_operations ext4_mb_seq_history_fops = {
- .owner = THIS_MODULE,
- .open = ext4_mb_seq_history_open,
- .read = seq_read,
- .write = ext4_mb_seq_history_write,
- .llseek = seq_lseek,
- .release = ext4_mb_seq_history_release,
-};
-
static void *ext4_mb_seq_groups_start(struct seq_file *seq, loff_t *pos)
{
struct super_block *sb = seq->private;
@@ -2396,82 +2195,6 @@
.release = seq_release,
};
-static void ext4_mb_history_release(struct super_block *sb)
-{
- struct ext4_sb_info *sbi = EXT4_SB(sb);
-
- if (sbi->s_proc != NULL) {
- remove_proc_entry("mb_groups", sbi->s_proc);
- if (sbi->s_mb_history_max)
- remove_proc_entry("mb_history", sbi->s_proc);
- }
- kfree(sbi->s_mb_history);
-}
-
-static void ext4_mb_history_init(struct super_block *sb)
-{
- struct ext4_sb_info *sbi = EXT4_SB(sb);
- int i;
-
- if (sbi->s_proc != NULL) {
- if (sbi->s_mb_history_max)
- proc_create_data("mb_history", S_IRUGO, sbi->s_proc,
- &ext4_mb_seq_history_fops, sb);
- proc_create_data("mb_groups", S_IRUGO, sbi->s_proc,
- &ext4_mb_seq_groups_fops, sb);
- }
-
- sbi->s_mb_history_cur = 0;
- spin_lock_init(&sbi->s_mb_history_lock);
- i = sbi->s_mb_history_max * sizeof(struct ext4_mb_history);
- sbi->s_mb_history = i ? kzalloc(i, GFP_KERNEL) : NULL;
- /* if we can't allocate history, then we simple won't use it */
-}
-
-static noinline_for_stack void
-ext4_mb_store_history(struct ext4_allocation_context *ac)
-{
- struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
- struct ext4_mb_history h;
-
- if (sbi->s_mb_history == NULL)
- return;
-
- if (!(ac->ac_op & sbi->s_mb_history_filter))
- return;
-
- h.op = ac->ac_op;
- h.pid = current->pid;
- h.ino = ac->ac_inode ? ac->ac_inode->i_ino : 0;
- h.orig = ac->ac_o_ex;
- h.result = ac->ac_b_ex;
- h.flags = ac->ac_flags;
- h.found = ac->ac_found;
- h.groups = ac->ac_groups_scanned;
- h.cr = ac->ac_criteria;
- h.tail = ac->ac_tail;
- h.buddy = ac->ac_buddy;
- h.merged = 0;
- if (ac->ac_op == EXT4_MB_HISTORY_ALLOC) {
- 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)
- h.merged = 1;
- h.goal = ac->ac_g_ex;
- h.result = ac->ac_f_ex;
- }
-
- spin_lock(&sbi->s_mb_history_lock);
- memcpy(sbi->s_mb_history + sbi->s_mb_history_cur, &h, sizeof(h));
- if (++sbi->s_mb_history_cur >= sbi->s_mb_history_max)
- sbi->s_mb_history_cur = 0;
- spin_unlock(&sbi->s_mb_history_lock);
-}
-
-#else
-#define ext4_mb_history_release(sb)
-#define ext4_mb_history_init(sb)
-#endif
-
/* Create and initialize ext4_group_info data for the given group. */
int ext4_mb_add_groupinfo(struct super_block *sb, ext4_group_t group,
@@ -2690,7 +2413,6 @@
sbi->s_mb_stats = MB_DEFAULT_STATS;
sbi->s_mb_stream_request = MB_DEFAULT_STREAM_THRESHOLD;
sbi->s_mb_order2_reqs = MB_DEFAULT_ORDER2_REQS;
- sbi->s_mb_history_filter = EXT4_MB_HISTORY_DEFAULT;
sbi->s_mb_group_prealloc = MB_DEFAULT_GROUP_PREALLOC;
sbi->s_locality_groups = alloc_percpu(struct ext4_locality_group);
@@ -2708,7 +2430,9 @@
spin_lock_init(&lg->lg_prealloc_lock);
}
- ext4_mb_history_init(sb);
+ if (sbi->s_proc)
+ proc_create_data("mb_groups", S_IRUGO, sbi->s_proc,
+ &ext4_mb_seq_groups_fops, sb);
if (sbi->s_journal)
sbi->s_journal->j_commit_callback = release_blocks_on_commit;
@@ -2788,7 +2512,8 @@
}
free_percpu(sbi->s_locality_groups);
- ext4_mb_history_release(sb);
+ if (sbi->s_proc)
+ remove_proc_entry("mb_groups", sbi->s_proc);
return 0;
}
@@ -3274,7 +2999,10 @@
atomic_inc(&sbi->s_bal_breaks);
}
- ext4_mb_store_history(ac);
+ if (ac->ac_op == EXT4_MB_HISTORY_ALLOC)
+ trace_ext4_mballoc_alloc(ac);
+ else
+ trace_ext4_mballoc_prealloc(ac);
}
/*
@@ -3774,7 +3502,6 @@
if (ac) {
ac->ac_sb = sb;
ac->ac_inode = pa->pa_inode;
- ac->ac_op = EXT4_MB_HISTORY_DISCARD;
}
while (bit < end) {
@@ -3794,7 +3521,7 @@
ac->ac_b_ex.fe_start = bit;
ac->ac_b_ex.fe_len = next - bit;
ac->ac_b_ex.fe_logical = 0;
- ext4_mb_store_history(ac);
+ trace_ext4_mballoc_discard(ac);
}
trace_ext4_mb_release_inode_pa(ac, pa, grp_blk_start + bit,
@@ -3829,9 +3556,6 @@
ext4_group_t group;
ext4_grpblk_t bit;
- if (ac)
- ac->ac_op = EXT4_MB_HISTORY_DISCARD;
-
trace_ext4_mb_release_group_pa(ac, pa);
BUG_ON(pa->pa_deleted == 0);
ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
@@ -3846,7 +3570,7 @@
ac->ac_b_ex.fe_start = bit;
ac->ac_b_ex.fe_len = pa->pa_len;
ac->ac_b_ex.fe_logical = 0;
- ext4_mb_store_history(ac);
+ trace_ext4_mballoc_discard(ac);
}
return 0;
@@ -4737,7 +4461,6 @@
ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
if (ac) {
- ac->ac_op = EXT4_MB_HISTORY_FREE;
ac->ac_inode = inode;
ac->ac_sb = sb;
}
@@ -4804,7 +4527,7 @@
ac->ac_b_ex.fe_group = block_group;
ac->ac_b_ex.fe_start = bit;
ac->ac_b_ex.fe_len = count;
- ext4_mb_store_history(ac);
+ trace_ext4_mballoc_free(ac);
}
err = ext4_mb_load_buddy(sb, block_group, &e4b);