mm/damon/core: implement per-scheme ops-handled filter-passed bytes stat

Implement a new per-DAMOS scheme statistic field, namely
sz_ops_filter_passed, using the changed damon_operations->apply_scheme()
interface.  It counts total bytes of memory that given DAMOS action tried
to be applied, and passed the operations layer handled region-internal
filters of the scheme.  DAMON API users can access it using DAMON-internal
safe access features such as damon_call() and/or damos_walk().

Link: https://lkml.kernel.org/r/20250106193401.109161-8-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/damon.h b/include/linux/damon.h
index da003173210f385f597a6defe16b71c66f9c5c18..2a93dbe06eccafcc6c57900e9198a5c7b148e38b 100644 (file)
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -286,6 +286,8 @@ struct damos_watermarks {
  * @sz_tried:  Total size of regions that the scheme is tried to be applied.
  * @nr_applied:        Total number of regions that the scheme is applied.
  * @sz_applied:        Total size of regions that the scheme is applied.
+ * @sz_ops_filter_passed:
+ *             Total bytes that passed ops layer-handled DAMOS filters.
  * @qt_exceeds: Total number of times the quota of the scheme has exceeded.
  *
  * "Tried an action to a region" in this context means the DAMOS core logic
@@ -310,6 +312,7 @@ struct damos_stat {
        unsigned long sz_tried;
        unsigned long nr_applied;
        unsigned long sz_applied;
+       unsigned long sz_ops_filter_passed;
        unsigned long qt_exceeds;
 };
 

diff --git a/mm/damon/core.c b/mm/damon/core.c
index c6ccb4825c5724f4f8131d34306d193ce42a5774..c4ce72a86d812b1960bf516671969257068168c4 100644 (file)
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -1362,13 +1362,15 @@ static bool damos_skip_charged_region(struct damon_target *t,
 }
 
 static void damos_update_stat(struct damos *s,
-               unsigned long sz_tried, unsigned long sz_applied)
+               unsigned long sz_tried, unsigned long sz_applied,
+               unsigned long sz_ops_filter_passed)
 {
        s->stat.nr_tried++;
        s->stat.sz_tried += sz_tried;
        if (sz_applied)
                s->stat.nr_applied++;
        s->stat.sz_applied += sz_applied;
+       s->stat.sz_ops_filter_passed += sz_ops_filter_passed;
 }
 
 static bool __damos_filter_out(struct damon_ctx *ctx, struct damon_target *t,
@@ -1586,7 +1588,7 @@ static void damos_apply_scheme(struct damon_ctx *c, struct damon_target *t,
                r->age = 0;
 
 update_stat:
-       damos_update_stat(s, sz, sz_applied);
+       damos_update_stat(s, sz, sz_applied, sz_ops_filter_passed);
 }
 
 static void damon_do_apply_schemes(struct damon_ctx *c,