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authorDave Chinner <dchinner@redhat.com>2011-07-08 14:14:34 +1000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-08-01 12:26:55 -0700
commit5e5b3d2ed3aee6f8bbe38c0945876aacce11ff03 (patch)
tree16b91161462ffbc0c838973343ea32e504827f19 /mm
parent564ea9dd5ab042cb2fe8373f4d627073706e1d4f (diff)
downloadlwn-5e5b3d2ed3aee6f8bbe38c0945876aacce11ff03.tar.gz
lwn-5e5b3d2ed3aee6f8bbe38c0945876aacce11ff03.zip
vmscan: add shrink_slab tracepoints
commit 095760730c1047c69159ce88021a7fa3833502c8 upstream. Stable note: This patch makes later patches easier to apply but otherwise has little to justify it. It is a diagnostic patch that was part of a series addressing excessive slab shrinking after GFP_NOFS failures. There is detailed information on the series' motivation at https://lkml.org/lkml/2011/6/2/42 . 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> Signed-off-by: Mel Gorman <mgorman@suse.de>
Diffstat (limited to 'mm')
-rw-r--r--mm/vmscan.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 6b0f8a60ca68..abc798167cf2 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -250,6 +250,7 @@ unsigned long shrink_slab(struct shrink_control *shrink,
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 @@ unsigned long shrink_slab(struct shrink_control *shrink,
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 @@ unsigned long shrink_slab(struct shrink_control *shrink,
}
shrinker->nr += total_scan;
+ trace_mm_shrink_slab_end(shrinker, shrink_ret, total_scan,
+ shrinker->nr);
}
up_read(&shrinker_rwsem);
out: