[PATCH V4 0/4] mm/damon: Do some small changes

[PATCH V4 0/4] mm/damon: Do some small changes

[Xin Hao]

V3 -> V4
	Fix kernel test compile warning of patch[4]

V2 -> V3
	Fix commit information patch[2], as suggested by SeongJae Park
	Add reviewed by SeongJae Park
	https://lore.kernel.org/linux-mm/20211111082034.13323-1-sj@kernel.org/

V1 -> V2
	Add reviewed by SeongJae Park
	Add two new patches

V1:
https://lore.kernel.org/linux-mm/cover.1636546262.git.xhao@linux.alibaba.com/


Xin Hao (4):
  mm/damon: Unified access_check function naming rules
  mm/damon: Add 'age' of region tracepoint support
  mm/damon/core: Using function abs() instead of diff_of()
  mm/damon: Remove some no need func definitions in damon.h file

 include/linux/damon.h        | 25 ++-----------------------
 include/trace/events/damon.h |  7 +++++--
 mm/damon/core.c              |  6 ++----
 mm/damon/paddr.c             |  8 ++++----
 mm/damon/vaddr.c             | 20 ++++++++++----------
 5 files changed, 23 insertions(+), 43 deletions(-)

--
2.31.0

[PATCH V4 1/4] mm/damon: Unified access_check function naming rules

[Xin Hao]

In damon/paddr.c file, two functions names start with underscore,
	static void __damon_pa_prepare_access_check(struct damon_ctx *ctx,
			struct damon_region *r)
	static void __damon_pa_prepare_access_check(struct damon_ctx *ctx,
			struct damon_region *r)
In damon/vaddr.c file, there are also two functions with the same function,
	static void damon_va_prepare_access_check(struct damon_ctx *ctx,
			struct mm_struct *mm, struct damon_region *r)
	static void damon_va_check_access(struct damon_ctx *ctx,
			struct mm_struct *mm, struct damon_region *r)

It makes sense to keep consistent, and it is not easy to be confused with
the function that call them.

Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/vaddr.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c
index 35fe49080ee9..905e0fc8a8ec 100644
--- a/mm/damon/vaddr.c
+++ b/mm/damon/vaddr.c
@@ -409,7 +409,7 @@ static void damon_va_mkold(struct mm_struct *mm, unsigned long addr)
  * Functions for the access checking of the regions
  */
 
-static void damon_va_prepare_access_check(struct damon_ctx *ctx,
+static void __damon_va_prepare_access_check(struct damon_ctx *ctx,
 			struct mm_struct *mm, struct damon_region *r)
 {
 	r->sampling_addr = damon_rand(r->ar.start, r->ar.end);
@@ -428,7 +428,7 @@ void damon_va_prepare_access_checks(struct damon_ctx *ctx)
 		if (!mm)
 			continue;
 		damon_for_each_region(r, t)
-			damon_va_prepare_access_check(ctx, mm, r);
+			__damon_va_prepare_access_check(ctx, mm, r);
 		mmput(mm);
 	}
 }
@@ -514,7 +514,7 @@ static bool damon_va_young(struct mm_struct *mm, unsigned long addr,
  * mm	'mm_struct' for the given virtual address space
  * r	the region to be checked
  */
-static void damon_va_check_access(struct damon_ctx *ctx,
+static void __damon_va_check_access(struct damon_ctx *ctx,
 			       struct mm_struct *mm, struct damon_region *r)
 {
 	static struct mm_struct *last_mm;
@@ -550,7 +550,7 @@ unsigned int damon_va_check_accesses(struct damon_ctx *ctx)
 		if (!mm)
 			continue;
 		damon_for_each_region(r, t) {
-			damon_va_check_access(ctx, mm, r);
+			__damon_va_check_access(ctx, mm, r);
 			max_nr_accesses = max(r->nr_accesses, max_nr_accesses);
 		}
 		mmput(mm);
-- 
2.31.0

[PATCH V4 2/4] mm/damon: Add 'age' of region tracepoint support

[Xin Hao]

In Damon, we can get age information by analyzing the nr_access change,
But short time sampling is not effective, we have to obtain enough data
for analysis through long time trace, this also means that we need to
consume more cpu resources and storage space.

Now the region add a new 'age' variable, we only need to get the change
of age value through a little time trace, for example, age has been
increasing to 141, but nr_access shows a value of 0 at the same time,
Through this，we can conclude that the region has a very low nr_access
value for a long time.

Fixes: 2fcb93629ad8 ("mm/damon: add a tracepoint")
Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
---
 include/trace/events/damon.h | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/include/trace/events/damon.h b/include/trace/events/damon.h
index 2f422f4f1fb9..99ffa601e351 100644
--- a/include/trace/events/damon.h
+++ b/include/trace/events/damon.h
@@ -22,6 +22,7 @@ TRACE_EVENT(damon_aggregated,
 		__field(unsigned long, start)
 		__field(unsigned long, end)
 		__field(unsigned int, nr_accesses)
+		__field(unsigned int, age)
 	),

 	TP_fast_assign(
@@ -30,11 +31,13 @@ TRACE_EVENT(damon_aggregated,
 		__entry->start = r->ar.start;
 		__entry->end = r->ar.end;
 		__entry->nr_accesses = r->nr_accesses;
+		__entry->age = r->age;
 	),

-	TP_printk("target_id=%lu nr_regions=%u %lu-%lu: %u",
+	TP_printk("target_id=%lu nr_regions=%u %lu-%lu: %u %u",
 			__entry->target_id, __entry->nr_regions,
-			__entry->start, __entry->end, __entry->nr_accesses)
+			__entry->start, __entry->end,
+			__entry->nr_accesses, __entry->age)
 );

 #endif /* _TRACE_DAMON_H */
--
2.31.0

[PATCH V4 3/4] mm/damon/core: Using function abs() instead of diff_of()

[Xin Hao]

In kernel, we can use abs(a - b) to get the absolute value,
So there is no need to redefine a new one.

Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/core.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/mm/damon/core.c b/mm/damon/core.c
index f37c17b53814..4d2c3a0c7c8a 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -757,8 +757,6 @@ static void damon_merge_two_regions(struct damon_target *t,
 	damon_destroy_region(r, t);
 }
 
-#define diff_of(a, b) (a > b ? a - b : b - a)
-
 /*
  * Merge adjacent regions having similar access frequencies
  *
@@ -772,13 +770,13 @@ static void damon_merge_regions_of(struct damon_target *t, unsigned int thres,
 	struct damon_region *r, *prev = NULL, *next;
 
 	damon_for_each_region_safe(r, next, t) {
-		if (diff_of(r->nr_accesses, r->last_nr_accesses) > thres)
+		if (abs(r->nr_accesses - r->last_nr_accesses) > thres)
 			r->age = 0;
 		else
 			r->age++;
 
 		if (prev && prev->ar.end == r->ar.start &&
-		    diff_of(prev->nr_accesses, r->nr_accesses) <= thres &&
+		    abs(prev->nr_accesses - r->nr_accesses) <= thres &&
 		    sz_damon_region(prev) + sz_damon_region(r) <= sz_limit)
 			damon_merge_two_regions(t, prev, r);
 		else
-- 
2.31.0

[PATCH V4 4/4] mm/damon: Remove some no need func definitions in damon.h file

[Xin Hao]

In the damon.h header file, some func definitions about VA & PA
can only be used in its own file, so there no need to define in
the header file, and the header file will looks cleaner.

If other files later call these functions, then put them to the
header file will not be late.

Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
---
 include/linux/damon.h | 25 ++-----------------------
 mm/damon/paddr.c      |  8 ++++----
 mm/damon/vaddr.c      | 12 ++++++------
 3 files changed, 12 insertions(+), 33 deletions(-)

diff --git a/include/linux/damon.h b/include/linux/damon.h
index 321de9d72360..8a73e825e0d5 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -461,34 +461,13 @@ int damon_stop(struct damon_ctx **ctxs, int nr_ctxs);
 #endif	/* CONFIG_DAMON */

 #ifdef CONFIG_DAMON_VADDR
-
-/* Monitoring primitives for virtual memory address spaces */
-void damon_va_init(struct damon_ctx *ctx);
-void damon_va_update(struct damon_ctx *ctx);
-void damon_va_prepare_access_checks(struct damon_ctx *ctx);
-unsigned int damon_va_check_accesses(struct damon_ctx *ctx);
-bool damon_va_target_valid(void *t);
-void damon_va_cleanup(struct damon_ctx *ctx);
-int damon_va_apply_scheme(struct damon_ctx *context, struct damon_target *t,
-		struct damon_region *r, struct damos *scheme);
-int damon_va_scheme_score(struct damon_ctx *context, struct damon_target *t,
-		struct damon_region *r, struct damos *scheme);
 void damon_va_set_primitives(struct damon_ctx *ctx);
-
+bool damon_va_target_valid(void *t);
 #endif	/* CONFIG_DAMON_VADDR */

 #ifdef CONFIG_DAMON_PADDR
-
-/* Monitoring primitives for the physical memory address space */
-void damon_pa_prepare_access_checks(struct damon_ctx *ctx);
-unsigned int damon_pa_check_accesses(struct damon_ctx *ctx);
-bool damon_pa_target_valid(void *t);
-int damon_pa_apply_scheme(struct damon_ctx *context, struct damon_target *t,
-		struct damon_region *r, struct damos *scheme);
-int damon_pa_scheme_score(struct damon_ctx *context, struct damon_target *t,
-		struct damon_region *r, struct damos *scheme);
 void damon_pa_set_primitives(struct damon_ctx *ctx);
-
+bool damon_pa_target_valid(void *t);
 #endif	/* CONFIG_DAMON_PADDR */

 #endif	/* _DAMON_H */
diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c
index a496d6f203d6..5c3a29d32638 100644
--- a/mm/damon/paddr.c
+++ b/mm/damon/paddr.c
@@ -73,7 +73,7 @@ static void __damon_pa_prepare_access_check(struct damon_ctx *ctx,
 	damon_pa_mkold(r->sampling_addr);
 }

-void damon_pa_prepare_access_checks(struct damon_ctx *ctx)
+static void damon_pa_prepare_access_checks(struct damon_ctx *ctx)
 {
 	struct damon_target *t;
 	struct damon_region *r;
@@ -192,7 +192,7 @@ static void __damon_pa_check_access(struct damon_ctx *ctx,
 	last_addr = r->sampling_addr;
 }

-unsigned int damon_pa_check_accesses(struct damon_ctx *ctx)
+static unsigned int damon_pa_check_accesses(struct damon_ctx *ctx)
 {
 	struct damon_target *t;
 	struct damon_region *r;
@@ -213,7 +213,7 @@ bool damon_pa_target_valid(void *t)
 	return true;
 }

-int damon_pa_apply_scheme(struct damon_ctx *ctx, struct damon_target *t,
+static int damon_pa_apply_scheme(struct damon_ctx *ctx, struct damon_target *t,
 		struct damon_region *r, struct damos *scheme)
 {
 	unsigned long addr;
@@ -246,7 +246,7 @@ int damon_pa_apply_scheme(struct damon_ctx *ctx, struct damon_target *t,
 	return 0;
 }

-int damon_pa_scheme_score(struct damon_ctx *context, struct damon_target *t,
+static int damon_pa_scheme_score(struct damon_ctx *context, struct damon_target *t,
 		struct damon_region *r, struct damos *scheme)
 {
 	switch (scheme->action) {
diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c
index 905e0fc8a8ec..eb1e955b5aba 100644
--- a/mm/damon/vaddr.c
+++ b/mm/damon/vaddr.c
@@ -271,7 +271,7 @@ static void __damon_va_init_regions(struct damon_ctx *ctx,
 }

 /* Initialize '->regions_list' of every target (task) */
-void damon_va_init(struct damon_ctx *ctx)
+static void damon_va_init(struct damon_ctx *ctx)
 {
 	struct damon_target *t;

@@ -355,7 +355,7 @@ static void damon_va_apply_three_regions(struct damon_target *t,
 /*
  * Update regions for current memory mappings
  */
-void damon_va_update(struct damon_ctx *ctx)
+static void damon_va_update(struct damon_ctx *ctx)
 {
 	struct damon_addr_range three_regions[3];
 	struct damon_target *t;
@@ -417,7 +417,7 @@ static void __damon_va_prepare_access_check(struct damon_ctx *ctx,
 	damon_va_mkold(mm, r->sampling_addr);
 }

-void damon_va_prepare_access_checks(struct damon_ctx *ctx)
+static void damon_va_prepare_access_checks(struct damon_ctx *ctx)
 {
 	struct damon_target *t;
 	struct mm_struct *mm;
@@ -538,7 +538,7 @@ static void __damon_va_check_access(struct damon_ctx *ctx,
 	last_addr = r->sampling_addr;
 }

-unsigned int damon_va_check_accesses(struct damon_ctx *ctx)
+static unsigned int damon_va_check_accesses(struct damon_ctx *ctx)
 {
 	struct damon_target *t;
 	struct mm_struct *mm;
@@ -602,7 +602,7 @@ static int damos_madvise(struct damon_target *target, struct damon_region *r,
 }
 #endif	/* CONFIG_ADVISE_SYSCALLS */

-int damon_va_apply_scheme(struct damon_ctx *ctx, struct damon_target *t,
+static int damon_va_apply_scheme(struct damon_ctx *ctx, struct damon_target *t,
 		struct damon_region *r, struct damos *scheme)
 {
 	int madv_action;
@@ -633,7 +633,7 @@ int damon_va_apply_scheme(struct damon_ctx *ctx, struct damon_target *t,
 	return damos_madvise(t, r, madv_action);
 }

-int damon_va_scheme_score(struct damon_ctx *context, struct damon_target *t,
+static int damon_va_scheme_score(struct damon_ctx *context, struct damon_target *t,
 		struct damon_region *r, struct damos *scheme)
 {

--
2.31.0