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/super.c b/fs/ext4/super.c
index e5b206a..12e726a 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -50,13 +50,6 @@
#define CREATE_TRACE_POINTS
#include <trace/events/ext4.h>
-static int default_mb_history_length = 1000;
-
-module_param_named(default_mb_history_length, default_mb_history_length,
- int, 0644);
-MODULE_PARM_DESC(default_mb_history_length,
- "Default number of entries saved for mb_history");
-
struct proc_dir_entry *ext4_proc_root;
static struct kset *ext4_kset;
@@ -1079,7 +1072,7 @@
Opt_journal_update, Opt_journal_dev,
Opt_journal_checksum, Opt_journal_async_commit,
Opt_abort, Opt_data_journal, Opt_data_ordered, Opt_data_writeback,
- Opt_data_err_abort, Opt_data_err_ignore, Opt_mb_history_length,
+ Opt_data_err_abort, Opt_data_err_ignore,
Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_quota, Opt_noquota,
Opt_ignore, Opt_barrier, Opt_nobarrier, Opt_err, Opt_resize,
@@ -1126,7 +1119,6 @@
{Opt_data_writeback, "data=writeback"},
{Opt_data_err_abort, "data_err=abort"},
{Opt_data_err_ignore, "data_err=ignore"},
- {Opt_mb_history_length, "mb_history_length=%u"},
{Opt_offusrjquota, "usrjquota="},
{Opt_usrjquota, "usrjquota=%s"},
{Opt_offgrpjquota, "grpjquota="},
@@ -1367,13 +1359,6 @@
case Opt_data_err_ignore:
clear_opt(sbi->s_mount_opt, DATA_ERR_ABORT);
break;
- case Opt_mb_history_length:
- if (match_int(&args[0], &option))
- return 0;
- if (option < 0)
- return 0;
- sbi->s_mb_history_max = option;
- break;
#ifdef CONFIG_QUOTA
case Opt_usrjquota:
qtype = USRQUOTA;
@@ -2435,7 +2420,6 @@
sbi->s_commit_interval = JBD2_DEFAULT_MAX_COMMIT_AGE * HZ;
sbi->s_min_batch_time = EXT4_DEF_MIN_BATCH_TIME;
sbi->s_max_batch_time = EXT4_DEF_MAX_BATCH_TIME;
- sbi->s_mb_history_max = default_mb_history_length;
set_opt(sbi->s_mount_opt, BARRIER);