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mm/compaction: split freepages without holding the zone lock

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We don't need to split freepages with holding the zone lock.  It will
cause more contention on zone lock so not desirable.

[rientjes@google.com: if __isolate_free_page() fails, avoid adding to freelist so we don't call map_pages() with it]
  Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1606211447001.43430@chino.kir.corp.google.com
Link: http://lkml.kernel.org/r/1464230275-25791-1-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Joonsoo Kim 2016-07-26 15:23:40 -07:00 committed by Linus Torvalds
parent 3b1d9ca65a
commit 66c64223ad
3 changed files with 33 additions and 42 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
include/linux/mm.h
View File

@ -537,7 +537,6 @@ void __put_page(struct page *page);
void put_pages_list(struct list_head *pages);
void split_page(struct page *page, unsigned int order);
int split_free_page(struct page *page);
/*
* Compound pages have a destructor function. Provide a

47
mm/compaction.c
View File

@ -64,13 +64,31 @@ static unsigned long release_freepages(struct list_head *freelist)
static void map_pages(struct list_head *list)
{
struct page *page;
unsigned int i, order, nr_pages;
struct page *page, *next;
LIST_HEAD(tmp_list);
list_for_each_entry(page, list, lru) {
arch_alloc_page(page, 0);
kernel_map_pages(page, 1, 1);
kasan_alloc_pages(page, 0);
list_for_each_entry_safe(page, next, list, lru) {
list_del(&page->lru);
order = page_private(page);
nr_pages = 1 << order;
set_page_private(page, 0);
set_page_refcounted(page);
arch_alloc_page(page, order);
kernel_map_pages(page, nr_pages, 1);
kasan_alloc_pages(page, order);
if (order)
split_page(page, order);
for (i = 0; i < nr_pages; i++) {
list_add(&page->lru, &tmp_list);
page++;
}
}
list_splice(&tmp_list, list);
}
static inline bool migrate_async_suitable(int migratetype)
@ -405,12 +423,13 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
unsigned long flags = 0;
bool locked = false;
unsigned long blockpfn = *start_pfn;
unsigned int order;
cursor = pfn_to_page(blockpfn);
/* Isolate free pages. */
for (; blockpfn < end_pfn; blockpfn++, cursor++) {
int isolated, i;
int isolated;
struct page *page = cursor;
/*
@ -476,17 +495,17 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
goto isolate_fail;
}
/* Found a free page, break it into order-0 pages */
isolated = split_free_page(page);
/* Found a free page, will break it into order-0 pages */
order = page_order(page);
isolated = __isolate_free_page(page, order);
if (!isolated)
break;
set_page_private(page, order);
total_isolated += isolated;
cc->nr_freepages += isolated;
for (i = 0; i < isolated; i++) {
list_add(&page->lru, freelist);
page++;
}
list_add_tail(&page->lru, freelist);
if (!strict && cc->nr_migratepages <= cc->nr_freepages) {
blockpfn += isolated;
break;
@ -605,7 +624,7 @@ isolate_freepages_range(struct compact_control *cc,
*/
}
/* split_free_page does not map the pages */
/* __isolate_free_page() does not map the pages */
map_pages(&freelist);
if (pfn < end_pfn) {
@ -1102,7 +1121,7 @@ static void isolate_freepages(struct compact_control *cc)
}
}
/* split_free_page does not map the pages */
/* __isolate_free_page() does not map the pages */
map_pages(freelist);
/*

27
mm/page_alloc.c
View File

@ -2526,33 +2526,6 @@ int __isolate_free_page(struct page *page, unsigned int order)
return 1UL << order;
}
/*
* Similar to split_page except the page is already free. As this is only
* being used for migration, the migratetype of the block also changes.
* As this is called with interrupts disabled, the caller is responsible
* for calling arch_alloc_page() and kernel_map_page() after interrupts
* are enabled.
*
* Note: this is probably too low level an operation for use in drivers.
* Please consult with lkml before using this in your driver.
*/
int split_free_page(struct page *page)
{
unsigned int order;
int nr_pages;
order = page_order(page);
nr_pages = __isolate_free_page(page, order);
if (!nr_pages)
return 0;
/* Split into individual pages */
set_page_refcounted(page);
split_page(page, order);
return nr_pages;
}
/*
* Update NUMA hit/miss statistics
*