vmscan: add shrink_slab tracepoints
It is impossible to understand what the shrinkers are actually doing
without instrumenting the code, so add a some tracepoints to allow
insight to be gained.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/mm/vmscan.c b/mm/vmscan.c
index d036e59..2552265 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -250,6 +250,7 @@
unsigned long long delta;
unsigned long total_scan;
unsigned long max_pass;
+ int shrink_ret = 0;
max_pass = do_shrinker_shrink(shrinker, shrink, 0);
delta = (4 * nr_pages_scanned) / shrinker->seeks;
@@ -274,9 +275,12 @@
total_scan = shrinker->nr;
shrinker->nr = 0;
+ trace_mm_shrink_slab_start(shrinker, shrink, total_scan,
+ nr_pages_scanned, lru_pages,
+ max_pass, delta, total_scan);
+
while (total_scan >= SHRINK_BATCH) {
long this_scan = SHRINK_BATCH;
- int shrink_ret;
int nr_before;
nr_before = do_shrinker_shrink(shrinker, shrink, 0);
@@ -293,6 +297,8 @@
}
shrinker->nr += total_scan;
+ trace_mm_shrink_slab_end(shrinker, shrink_ret, total_scan,
+ shrinker->nr);
}
up_read(&shrinker_rwsem);
out: