@@ -357,6 +357,7 @@ struct damon_operations {
* @after_wmarks_check: Called after each schemes' watermarks check.
* @after_sampling: Called after each sampling.
* @after_aggregation: Called after each aggregation.
+ * @before_damos_apply: Called before applying DAMOS action.
* @before_terminate: Called before terminating the monitoring.
* @private: User private data.
*
@@ -385,6 +386,10 @@ struct damon_callback {
int (*after_wmarks_check)(struct damon_ctx *context);
int (*after_sampling)(struct damon_ctx *context);
int (*after_aggregation)(struct damon_ctx *context);
+ int (*before_damos_apply)(struct damon_ctx *context,
+ struct damon_target *target,
+ struct damon_region *region,
+ struct damos *scheme);
void (*before_terminate)(struct damon_ctx *context);
};
@@ -772,6 +772,7 @@ 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;
+ int err = 0;
if (c->ops.apply_scheme) {
if (quota->esz && quota->charged_sz + sz > quota->esz) {
@@ -782,7 +783,10 @@ static void damos_apply_scheme(struct damon_ctx *c, struct damon_target *t,
damon_split_region_at(t, r, sz);
}
ktime_get_coarse_ts64(&begin);
- sz_applied = c->ops.apply_scheme(c, t, r, s);
+ if (c->callback.before_damos_apply)
+ err = c->callback.before_damos_apply(c, t, r, s);
+ if (!err)
+ sz_applied = c->ops.apply_scheme(c, t, r, s);
ktime_get_coarse_ts64(&end);
quota->total_charged_ns += timespec64_to_ns(&end) -
timespec64_to_ns(&begin);
Getting DAMON monitoring results of only specific access pattern (e.g., getting address ranges of memory that not accessed at all for two minutes) can be useful for efficient monitoring of the system. The information can also be helpful for deep level investigation of DAMON-based operation schemes. For that, users need to record (in case of the user space users) or iterate (in case of the kernel space users) full monitoring results and filter it out for the specific access pattern. In case of the DAMOS investigation, users will even need to simulate DAMOS' quota and prioritization mechanisms. It's inefficient and complex. Add a new DAMON callback that will be called before each scheme is applied to each region. DAMON kernel API users will be able to do the query-like monitoring results collection, or DAMOS investigation in an efficient and simple way using it. Commits for providing the capability to the user space users will follow. Signed-off-by: SeongJae Park <sj@kernel.org> --- include/linux/damon.h | 5 +++++ mm/damon/core.c | 6 +++++- 2 files changed, 10 insertions(+), 1 deletion(-)