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/ext4.h b/fs/ext4/ext4.h
index b491576..c508cf7 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -65,6 +65,12 @@
/* data type for block group number */
typedef unsigned int ext4_group_t;
+/*
+ * Flags used in mballoc's allocation_context flags field.
+ *
+ * Also used to show what's going on for debugging purposes when the
+ * flag field is exported via the traceport interface
+ */
/* prefer goal again. length */
#define EXT4_MB_HINT_MERGE 0x0001
@@ -971,14 +977,6 @@
unsigned long s_mb_last_group;
unsigned long s_mb_last_start;
- /* history to debug policy */
- struct ext4_mb_history *s_mb_history;
- int s_mb_history_cur;
- int s_mb_history_max;
- int s_mb_history_num;
- spinlock_t s_mb_history_lock;
- int s_mb_history_filter;
-
/* stats for buddy allocator */
spinlock_t s_mb_pa_lock;
atomic_t s_bal_reqs; /* number of reqs with len > 1 */