Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 09576073 authored by Dave Chinner's avatar Dave Chinner Committed by Al Viro
Browse files

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: default avatarDave Chinner <dchinner@redhat.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent a9049376

include/trace/events/vmscan.h

+77 −0
Original line number Diff line number Diff line
@@ -179,6 +179,83 @@ DEFINE_EVENT(mm_vmscan_direct_reclaim_end_template, mm_vmscan_memcg_softlimit_re 
	TP_ARGS(nr_reclaimed)

);



TRACE_EVENT(mm_shrink_slab_start,

	TP_PROTO(struct shrinker *shr, struct shrink_control *sc,

		long nr_objects_to_shrink, unsigned long pgs_scanned,

		unsigned long lru_pgs, unsigned long cache_items,

		unsigned long long delta, unsigned long total_scan),



	TP_ARGS(shr, sc, nr_objects_to_shrink, pgs_scanned, lru_pgs,

		cache_items, delta, total_scan),



	TP_STRUCT__entry(

		__field(struct shrinker *, shr)

		__field(void *, shrink)

		__field(long, nr_objects_to_shrink)

		__field(gfp_t, gfp_flags)

		__field(unsigned long, pgs_scanned)

		__field(unsigned long, lru_pgs)

		__field(unsigned long, cache_items)

		__field(unsigned long long, delta)

		__field(unsigned long, total_scan)

	),



	TP_fast_assign(

		__entry->shr = shr;

		__entry->shrink = shr->shrink;

		__entry->nr_objects_to_shrink = nr_objects_to_shrink;

		__entry->gfp_flags = sc->gfp_mask;

		__entry->pgs_scanned = pgs_scanned;

		__entry->lru_pgs = lru_pgs;

		__entry->cache_items = cache_items;

		__entry->delta = delta;

		__entry->total_scan = total_scan;

	),



	TP_printk("%pF %p: objects to shrink %ld gfp_flags %s pgs_scanned %ld lru_pgs %ld cache items %ld delta %lld total_scan %ld",

		__entry->shrink,

		__entry->shr,

		__entry->nr_objects_to_shrink,

		show_gfp_flags(__entry->gfp_flags),

		__entry->pgs_scanned,

		__entry->lru_pgs,

		__entry->cache_items,

		__entry->delta,

		__entry->total_scan)

);



TRACE_EVENT(mm_shrink_slab_end,

	TP_PROTO(struct shrinker *shr, int shrinker_retval,

		long unused_scan_cnt, long new_scan_cnt),



	TP_ARGS(shr, shrinker_retval, unused_scan_cnt, new_scan_cnt),



	TP_STRUCT__entry(

		__field(struct shrinker *, shr)

		__field(void *, shrink)

		__field(long, unused_scan)

		__field(long, new_scan)

		__field(int, retval)

		__field(long, total_scan)

	),



	TP_fast_assign(

		__entry->shr = shr;

		__entry->shrink = shr->shrink;

		__entry->unused_scan = unused_scan_cnt;

		__entry->new_scan = new_scan_cnt;

		__entry->retval = shrinker_retval;

		__entry->total_scan = new_scan_cnt - unused_scan_cnt;

	),



	TP_printk("%pF %p: unused scan count %ld new scan count %ld total_scan %ld last shrinker return val %d",

		__entry->shrink,

		__entry->shr,

		__entry->unused_scan,

		__entry->new_scan,

		__entry->total_scan,

		__entry->retval)

);



DECLARE_EVENT_CLASS(mm_vmscan_lru_isolate_template,

mm/vmscan.c

+7 −1
Original line number Diff line number Diff line
@@ -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: