diff mbox series

[v1,1/2] mm/damon: have damon_get_folio return folio even for tail pages

Message ID 20250116144436.3947318-1-usamaarif642@gmail.com (mailing list archive)
State New
Headers show
Series [v1,1/2] mm/damon: have damon_get_folio return folio even for tail pages | expand

Commit Message

Usama Arif Jan. 16, 2025, 2:44 p.m. UTC 
This effectively adds support for large folios in damon for paddr,
as damon_pa_mkold/young won't get a null folio from this function
and won't ignore it, hence access will be checked and reported.
This also means that larger folios will be considered for
different DAMOS actions like pageout, prioritization and migration.
As these DAMOS actions will consider larger folios, iterate through
the region at folio_size and not PAGE_SIZE intervals.
This should not have an affect on vaddr, as damon_young_pmd_entry
considers pmd entries.

Signed-off-by: Usama Arif <usamaarif642@gmail.com>
---
 mm/damon/ops-common.c |  2 +-
 mm/damon/paddr.c      | 24 ++++++++++++++++++------
 2 files changed, 19 insertions(+), 7 deletions(-)

Comments

SeongJae Park Jan. 16, 2025, 6:49 p.m. UTC | #1 
On Thu, 16 Jan 2025 14:44:35 +0000 Usama Arif <usamaarif642@gmail.com> wrote:

> This effectively adds support for large folios in damon for paddr,
> as damon_pa_mkold/young won't get a null folio from this function
> and won't ignore it, hence access will be checked and reported.
> This also means that larger folios will be considered for
> different DAMOS actions like pageout, prioritization and migration.
> As these DAMOS actions will consider larger folios, iterate through
> the region at folio_size and not PAGE_SIZE intervals.
> This should not have an affect on vaddr, as damon_young_pmd_entry
> considers pmd entries.

This patch will improve both accuracy of monitoring results and efficiency of
DAMOS for paddr use cases on THP-enabled systems.  Thank you Usama!

> 
> Signed-off-by: Usama Arif <usamaarif642@gmail.com>

Reviewed-by: SeongJae Park <sj@kernel.org>


Thanks,
SJ

[...]
diff mbox series

Patch

diff --git a/mm/damon/ops-common.c b/mm/damon/ops-common.c
index d25d99cb5f2b..d511be201c4c 100644
--- a/mm/damon/ops-common.c
+++ b/mm/damon/ops-common.c
@@ -24,7 +24,7 @@  struct folio *damon_get_folio(unsigned long pfn)
 	struct page *page = pfn_to_online_page(pfn);
 	struct folio *folio;
 
-	if (!page || PageTail(page))
+	if (!page)
 		return NULL;
 
 	folio = page_folio(page);
diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c
index bd8cfe10121b..c0ccf4fade24 100644
--- a/mm/damon/paddr.c
+++ b/mm/damon/paddr.c
@@ -266,11 +266,14 @@  static unsigned long damon_pa_pageout(struct damon_region *r, struct damos *s,
 		damos_add_filter(s, filter);
 	}
 
-	for (addr = r->ar.start; addr < r->ar.end; addr += PAGE_SIZE) {
+	addr = r->ar.start;
+	while (addr < r->ar.end) {
 		struct folio *folio = damon_get_folio(PHYS_PFN(addr));
 
-		if (!folio)
+		if (!folio) {
+			addr += PAGE_SIZE;
 			continue;
+		}
 
 		if (damos_pa_filter_out(s, folio))
 			goto put_folio;
@@ -286,6 +289,7 @@  static unsigned long damon_pa_pageout(struct damon_region *r, struct damos *s,
 		else
 			list_add(&folio->lru, &folio_list);
 put_folio:
+		addr += folio_size(folio);
 		folio_put(folio);
 	}
 	if (install_young_filter)
@@ -301,11 +305,14 @@  static inline unsigned long damon_pa_mark_accessed_or_deactivate(
 {
 	unsigned long addr, applied = 0;
 
-	for (addr = r->ar.start; addr < r->ar.end; addr += PAGE_SIZE) {
+	addr = r->ar.start;
+	while (addr < r->ar.end) {
 		struct folio *folio = damon_get_folio(PHYS_PFN(addr));
 
-		if (!folio)
+		if (!folio) {
+			addr += PAGE_SIZE;
 			continue;
+		}
 
 		if (damos_pa_filter_out(s, folio))
 			goto put_folio;
@@ -318,6 +325,7 @@  static inline unsigned long damon_pa_mark_accessed_or_deactivate(
 			folio_deactivate(folio);
 		applied += folio_nr_pages(folio);
 put_folio:
+		addr += folio_size(folio);
 		folio_put(folio);
 	}
 	return applied * PAGE_SIZE;
@@ -464,11 +472,14 @@  static unsigned long damon_pa_migrate(struct damon_region *r, struct damos *s,
 	unsigned long addr, applied;
 	LIST_HEAD(folio_list);
 
-	for (addr = r->ar.start; addr < r->ar.end; addr += PAGE_SIZE) {
+	addr = r->ar.start;
+	while (addr < r->ar.end) {
 		struct folio *folio = damon_get_folio(PHYS_PFN(addr));
 
-		if (!folio)
+		if (!folio) {
+			addr += PAGE_SIZE;
 			continue;
+		}
 
 		if (damos_pa_filter_out(s, folio))
 			goto put_folio;
@@ -479,6 +490,7 @@  static unsigned long damon_pa_migrate(struct damon_region *r, struct damos *s,
 			goto put_folio;
 		list_add(&folio->lru, &folio_list);
 put_folio:
+		addr += folio_size(folio);
 		folio_put(folio);
 	}
 	applied = damon_pa_migrate_pages(&folio_list, s->target_nid);