The patch titled
Subject: mm, page_alloc: avoid page_to_pfn() in move_freepages()
has been added to the -mm tree. Its filename is
mm-page_alloc-avoid-page_to_pfn-in-move_freepages.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-page_alloc-avoid-page_to_pfn-in-move_freepages.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-page_alloc-avoid-page_to_pfn-in-move_freepages.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Subject: mm, page_alloc: avoid page_to_pfn() in move_freepages()
The start_pfn and end_pfn are already available in move_freepages_block(),
there is no need to go back and forth between page and pfn in
move_freepages and move_freepages_block, and pfn_valid_within() should
validate pfn first before touching the page.
Link: https://lkml.kernel.org/r/20210323131215.934472-1-liushixin2@xxxxxxxxxx
Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Signed-off-by: Liu Shixin <liushixin2@xxxxxxxxxx>
Reviewed-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 28 +++++++++++++---------------
1 file changed, 13 insertions(+), 15 deletions(-)
--- a/mm/page_alloc.c~mm-page_alloc-avoid-page_to_pfn-in-move_freepages
+++ a/mm/page_alloc.c
@@ -2425,19 +2425,21 @@ static inline struct page *__rmqueue_cma
* boundary. If alignment is required, use move_freepages_block()
*/
static int move_freepages(struct zone *zone,
- struct page *start_page, struct page *end_page,
+ unsigned long start_pfn, unsigned long end_pfn,
int migratetype, int *num_movable)
{
struct page *page;
+ unsigned long pfn;
unsigned int order;
int pages_moved = 0;
- for (page = start_page; page <= end_page;) {
- if (!pfn_valid_within(page_to_pfn(page))) {
- page++;
+ for (pfn = start_pfn; pfn <= end_pfn;) {
+ if (!pfn_valid_within(pfn)) {
+ pfn++;
continue;
}
+ page = pfn_to_page(pfn);
if (!PageBuddy(page)) {
/*
* We assume that pages that could be isolated for
@@ -2447,8 +2449,7 @@ static int move_freepages(struct zone *z
if (num_movable &&
(PageLRU(page) || __PageMovable(page)))
(*num_movable)++;
-
- page++;
+ pfn++;
continue;
}
@@ -2458,7 +2459,7 @@ static int move_freepages(struct zone *z
order = buddy_order(page);
move_to_free_list(page, zone, order, migratetype);
- page += 1 << order;
+ pfn += 1 << order;
pages_moved += 1 << order;
}
@@ -2468,25 +2469,22 @@ static int move_freepages(struct zone *z
int move_freepages_block(struct zone *zone, struct page *page,
int migratetype, int *num_movable)
{
- unsigned long start_pfn, end_pfn;
- struct page *start_page, *end_page;
+ unsigned long start_pfn, end_pfn, pfn;
if (num_movable)
*num_movable = 0;
- start_pfn = page_to_pfn(page);
- start_pfn = start_pfn & ~(pageblock_nr_pages-1);
- start_page = pfn_to_page(start_pfn);
- end_page = start_page + pageblock_nr_pages - 1;
+ pfn = page_to_pfn(page);
+ start_pfn = pfn & ~(pageblock_nr_pages - 1);
end_pfn = start_pfn + pageblock_nr_pages - 1;
/* Do not cross zone boundaries */
if (!zone_spans_pfn(zone, start_pfn))
- start_page = page;
+ start_pfn = pfn;
if (!zone_spans_pfn(zone, end_pfn))
return 0;
- return move_freepages(zone, start_page, end_page, migratetype,
+ return move_freepages(zone, start_pfn, end_pfn, migratetype,
num_movable);
}
_
Patches currently in -mm which might be from wangkefeng.wang@xxxxxxxxxx are
mm-page_alloc-avoid-page_to_pfn-in-move_freepages.patch
