The patch titled
Subject: mm/page_alloc: track range of active PCP lists during bulk free
has been added to the -mm tree. Its filename is
mm-page_alloc-track-range-of-active-pcp-lists-during-bulk-free.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-page_alloc-track-range-of-active-pcp-lists-during-bulk-free.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-page_alloc-track-range-of-active-pcp-lists-during-bulk-free.patch
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------------------------------------------------------
From: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Subject: mm/page_alloc: track range of active PCP lists during bulk free
free_pcppages_bulk() frees pages in a round-robin fashion. Originally,
this was dealing only with migratetypes but storing high-order pages means
that there can be many more empty lists that are uselessly checked. Track
the minimum and maximum active pindex to reduce the search space.
Link: https://lkml.kernel.org/r/20220217002227.5739-3-mgorman@xxxxxxxxxxxxxxxxxxx
Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Aaron Lu <aaron.lu@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 17 +++++++++++++----
1 file changed, 13 insertions(+), 4 deletions(-)
--- a/mm/page_alloc.c~mm-page_alloc-track-range-of-active-pcp-lists-during-bulk-free
+++ a/mm/page_alloc.c
@@ -1450,6 +1450,8 @@ static void free_pcppages_bulk(struct zo
struct per_cpu_pages *pcp)
{
int pindex = 0;
+ int min_pindex = 0;
+ int max_pindex = NR_PCP_LISTS - 1;
int batch_free = 0;
int nr_freed = 0;
unsigned int order;
@@ -1475,13 +1477,20 @@ static void free_pcppages_bulk(struct zo
*/
do {
batch_free++;
- if (++pindex == NR_PCP_LISTS)
- pindex = 0;
+ if (++pindex > max_pindex)
+ pindex = min_pindex;
list = &pcp->lists[pindex];
- } while (list_empty(list));
+ if (!list_empty(list))
+ break;
+
+ if (pindex == max_pindex)
+ max_pindex--;
+ if (pindex == min_pindex)
+ min_pindex++;
+ } while (1);
/* This is the only non-empty list. Free them all. */
- if (batch_free == NR_PCP_LISTS)
+ if (batch_free >= max_pindex - min_pindex)
batch_free = count;
order = pindex_to_order(pindex);
_
Patches currently in -mm which might be from mgorman@xxxxxxxxxxxxxxxxxxx are
mm-page_alloc-fetch-the-correct-pcp-buddy-during-bulk-free.patch
mm-page_alloc-track-range-of-active-pcp-lists-during-bulk-free.patch
mm-page_alloc-simplify-how-many-pages-are-selected-per-pcp-list-during-bulk-free.patch
mm-page_alloc-drain-the-requested-list-first-during-bulk-free.patch
mm-page_alloc-free-pages-in-a-single-pass-during-bulk-free.patch
mm-page_alloc-limit-number-of-high-order-pages-on-pcp-during-bulk-free.patch
