* [PATCH 0/2] Follow-up to Leave IRQs enabled for per-cpu page allocations
@ 2022-11-22 13:12 Mel Gorman
2022-11-22 13:12 ` [PATCH 1/2] mm/page_alloc: Leave IRQs enabled for per-cpu page allocations -fix Mel Gorman
2022-11-22 13:12 ` [PATCH 2/2] mm/page_alloc: Simplify locking during free_unref_page_list Mel Gorman
0 siblings, 2 replies; 3+ messages in thread
From: Mel Gorman @ 2022-11-22 13:12 UTC (permalink / raw)
To: Andrew Morton
Cc: Hugh Dickins, Yu Zhao, Vlastimil Babka, Marcelo Tosatti,
Michal Hocko, Marek Szyprowski, LKML, Linux-MM, Mel Gorman
The following two patches are a fixup patch and a simplification as
suggested by Vlastimil Babka.
mm/page_alloc.c | 29 +++++++++++------------------
1 file changed, 11 insertions(+), 18 deletions(-)
--
2.35.3
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH 1/2] mm/page_alloc: Leave IRQs enabled for per-cpu page allocations -fix
2022-11-22 13:12 [PATCH 0/2] Follow-up to Leave IRQs enabled for per-cpu page allocations Mel Gorman
@ 2022-11-22 13:12 ` Mel Gorman
2022-11-22 13:12 ` [PATCH 2/2] mm/page_alloc: Simplify locking during free_unref_page_list Mel Gorman
1 sibling, 0 replies; 3+ messages in thread
From: Mel Gorman @ 2022-11-22 13:12 UTC (permalink / raw)
To: Andrew Morton
Cc: Hugh Dickins, Yu Zhao, Vlastimil Babka, Marcelo Tosatti,
Michal Hocko, Marek Szyprowski, LKML, Linux-MM, Mel Gorman
As noted by Vlastimil Babka, the migratetype might be wrong if a PCP was
not locked so check the migrate type early. Similarly the !pcp check is
generally unlikely so explicitly tagging it makes sense.
This is a fix for the mm-unstable patch
mm-page_alloc-leave-irqs-enabled-for-per-cpu-page-allocations.patch
Reported-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
---
mm/page_alloc.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 323fec05c4c6..445066617204 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3516,6 +3516,7 @@ void free_unref_page_list(struct list_head *list)
struct zone *zone = page_zone(page);
list_del(&page->lru);
+ migratetype = get_pcppage_migratetype(page);
/* Different zone, different pcp lock. */
if (zone != locked_zone) {
@@ -3530,7 +3531,7 @@ void free_unref_page_list(struct list_head *list)
*/
pcp_trylock_prepare(UP_flags);
pcp = pcp_spin_trylock(zone->per_cpu_pageset);
- if (!pcp) {
+ if (unlikely(!pcp)) {
pcp_trylock_finish(UP_flags);
free_one_page(zone, page, page_to_pfn(page),
0, migratetype, FPI_NONE);
@@ -3545,7 +3546,6 @@ void free_unref_page_list(struct list_head *list)
* Non-isolated types over MIGRATE_PCPTYPES get added
* to the MIGRATE_MOVABLE pcp list.
*/
- migratetype = get_pcppage_migratetype(page);
if (unlikely(migratetype >= MIGRATE_PCPTYPES))
migratetype = MIGRATE_MOVABLE;
--
2.35.3
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [PATCH 2/2] mm/page_alloc: Simplify locking during free_unref_page_list
2022-11-22 13:12 [PATCH 0/2] Follow-up to Leave IRQs enabled for per-cpu page allocations Mel Gorman
2022-11-22 13:12 ` [PATCH 1/2] mm/page_alloc: Leave IRQs enabled for per-cpu page allocations -fix Mel Gorman
@ 2022-11-22 13:12 ` Mel Gorman
1 sibling, 0 replies; 3+ messages in thread
From: Mel Gorman @ 2022-11-22 13:12 UTC (permalink / raw)
To: Andrew Morton
Cc: Hugh Dickins, Yu Zhao, Vlastimil Babka, Marcelo Tosatti,
Michal Hocko, Marek Szyprowski, LKML, Linux-MM, Mel Gorman
While freeing a large list, the zone lock will be released and reacquired
to avoid long hold times since commit c24ad77d962c ("mm/page_alloc.c: avoid
excessive IRQ disabled times in free_unref_page_list()"). As suggested
by Vlastimil Babka, the lockrelease/reacquire logic can be simplified by
reusing the logic that acquires a different lock when changing zones.
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
---
mm/page_alloc.c | 25 +++++++++----------------
1 file changed, 9 insertions(+), 16 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 445066617204..08e32daf0918 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3518,13 +3518,19 @@ void free_unref_page_list(struct list_head *list)
list_del(&page->lru);
migratetype = get_pcppage_migratetype(page);
- /* Different zone, different pcp lock. */
- if (zone != locked_zone) {
+ /*
+ * Either different zone requiring a different pcp lock or
+ * excessive lock hold times when freeing a large list of
+ * pages.
+ */
+ if (zone != locked_zone || batch_count == SWAP_CLUSTER_MAX) {
if (pcp) {
pcp_spin_unlock(pcp);
pcp_trylock_finish(UP_flags);
}
+ batch_count = 0;
+
/*
* trylock is necessary as pages may be getting freed
* from IRQ or SoftIRQ context after an IO completion.
@@ -3539,7 +3545,6 @@ void free_unref_page_list(struct list_head *list)
continue;
}
locked_zone = zone;
- batch_count = 0;
}
/*
@@ -3551,19 +3556,7 @@ void free_unref_page_list(struct list_head *list)
trace_mm_page_free_batched(page);
free_unref_page_commit(zone, pcp, page, migratetype, 0);
-
- /*
- * Guard against excessive lock hold times when freeing
- * a large list of pages. Lock will be reacquired if
- * necessary on the next iteration.
- */
- if (++batch_count == SWAP_CLUSTER_MAX) {
- pcp_spin_unlock(pcp);
- pcp_trylock_finish(UP_flags);
- batch_count = 0;
- pcp = NULL;
- locked_zone = NULL;
- }
+ batch_count++;
}
if (pcp) {
--
2.35.3
^ permalink raw reply related [flat|nested] 3+ messages in thread
end of thread, other threads:[~2022-11-22 13:13 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-11-22 13:12 [PATCH 0/2] Follow-up to Leave IRQs enabled for per-cpu page allocations Mel Gorman
2022-11-22 13:12 ` [PATCH 1/2] mm/page_alloc: Leave IRQs enabled for per-cpu page allocations -fix Mel Gorman
2022-11-22 13:12 ` [PATCH 2/2] mm/page_alloc: Simplify locking during free_unref_page_list Mel Gorman
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.