mm/damon: ask apply_scheme() to report filter-passed region-internal bytes

Some DAMOS filter types including those for young page, anon page, and
belonging memcg are handled by underlying DAMON operations set
implementation, via damon_operations->apply_scheme() interface.  How many
bytes of the region have passed the filter can be useful for DAMOS scheme
tuning and access pattern monitoring.  Modify the interface to let the
callback implementation reports back the number if possible.

Link: https://lkml.kernel.org/r/20250106193401.109161-5-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 b85eae388f5bcdb051d8d55cf3109ecd09c1296a..da003173210f385f597a6defe16b71c66f9c5c18 100644 (file)
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -529,7 +529,8 @@ enum damon_ops_id {
  * @apply_scheme is called from @kdamond when a region for user provided
  * DAMON-based operation scheme is found.  It should apply the scheme's action
  * to the region and return bytes of the region that the action is successfully
- * applied.
+ * applied.  It should also report how many bytes of the region has passed
+ * filters (&struct damos_filter) that handled by itself.
  * @target_valid should check whether the target is still valid for the
  * monitoring.
  * @cleanup is called from @kdamond just before its termination.
@@ -546,7 +547,7 @@ struct damon_operations {
                        struct damos *scheme);
        unsigned long (*apply_scheme)(struct damon_ctx *context,
                        struct damon_target *t, struct damon_region *r,
-                       struct damos *scheme);
+                       struct damos *scheme, unsigned long *sz_filter_passed);
        bool (*target_valid)(struct damon_target *t);
        void (*cleanup)(struct damon_ctx *context);
 };

diff --git a/mm/damon/core.c b/mm/damon/core.c
index d02a7d6da855cf67b460453e798b7daf56082f9f..c6ccb4825c5724f4f8131d34306d193ce42a5774 100644 (file)
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -1523,6 +1523,7 @@ static void damos_apply_scheme(struct damon_ctx *c, struct damon_target *t,
        unsigned long sz = damon_sz_region(r);
        struct timespec64 begin, end;
        unsigned long sz_applied = 0;
+       unsigned long sz_ops_filter_passed = 0;
        int err = 0;
        /*
         * We plan to support multiple context per kdamond, as DAMON sysfs
@@ -1568,7 +1569,8 @@ static void damos_apply_scheme(struct damon_ctx *c, struct damon_target *t,
                if (!err) {
                        trace_damos_before_apply(cidx, sidx, tidx, r,
                                        damon_nr_regions(t), do_trace);
-                       sz_applied = c->ops.apply_scheme(c, t, r, s);
+                       sz_applied = c->ops.apply_scheme(c, t, r, s,
+                                       &sz_ops_filter_passed);
                }
                damos_walk_call_walk(c, t, r, s);
                ktime_get_coarse_ts64(&end);

diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c
index a9ff35341d65d22d89dec521c374ab9bb58a4f64..3530ef9c80bd76bdc8272e32d2dbe96d419a6b79 100644 (file)
--- a/mm/damon/paddr.c
+++ b/mm/damon/paddr.c
@@ -477,7 +477,7 @@ put_folio:
 
 static unsigned long damon_pa_apply_scheme(struct damon_ctx *ctx,
                struct damon_target *t, struct damon_region *r,
-               struct damos *scheme)
+               struct damos *scheme, unsigned long *sz_filter_passed)
 {
        switch (scheme->action) {
        case DAMOS_PAGEOUT:

diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c
index b9eaa20b73b9abca3efbc0673357c5fa1caa7579..a6174f725bd7bfa7d0a1b0e75021377721788ac9 100644 (file)
--- a/mm/damon/vaddr.c
+++ b/mm/damon/vaddr.c
@@ -655,7 +655,7 @@ static unsigned long damos_madvise(struct damon_target *target,
 
 static unsigned long damon_va_apply_scheme(struct damon_ctx *ctx,
                struct damon_target *t, struct damon_region *r,
-               struct damos *scheme)
+               struct damos *scheme, unsigned long *sz_filter_passed)
 {
        int madv_action;