2009-06-12 01:28:24

by Kamezawa Hiroyuki

[permalink] [raw]
Subject: [BUGFIX][PATCH] fix lumpy reclaim lru handiling at isolate_lru_pages v2

Sorry for noisy posts. I hope this should be the last trial.
Thank you for all helps.

-Kame
==
From: KAMEZAWA Hiroyuki <[email protected]>

At lumpy reclaim, a page failed to be taken by __isolate_lru_page() can
be pushed back to "src" list by list_move(). But the page may not be from
"src" list. This pushes the page back to wrong LRU.
And list_move() itself is unnecessary because the page is
not on top of LRU. Then, leave it as it is if __isolate_lru_page() fails.

Changelog: v1->v2
- removed buggy break.

Reviewed-by: Minchan Kim <[email protected]>
Reviewed-by: KOSAKI Motohiro <[email protected]>
Acked-by: Mel Gorman <[email protected]>
Signed-off-by: KAMEZAWA Hiroyuki <[email protected]>
---
mm/vmscan.c | 10 +---------
1 file changed, 1 insertion(+), 9 deletions(-)

Index: lumpy-reclaim-trial/mm/vmscan.c
===================================================================
--- lumpy-reclaim-trial.orig/mm/vmscan.c
+++ lumpy-reclaim-trial/mm/vmscan.c
@@ -936,18 +936,10 @@ static unsigned long isolate_lru_pages(u
/* Check that we have not crossed a zone boundary. */
if (unlikely(page_zone_id(cursor_page) != zone_id))
continue;
- switch (__isolate_lru_page(cursor_page, mode, file)) {
- case 0:
+ if (__isolate_lru_page(cursor_page, mode, file) == 0) {
list_move(&cursor_page->lru, dst);
nr_taken++;
scan++;
- break;
-
- case -EBUSY:
- /* else it is being freed elsewhere */
- list_move(&cursor_page->lru, src);
- default:
- break; /* ! on LRU or wrong list */
}
}
}


2009-06-12 01:30:19

by Kamezawa Hiroyuki

[permalink] [raw]
Subject: [BUGFIX][PATCH] memcg fix lru rotation in isolate_pages v2

From: KAMEZAWA Hiroyuki <[email protected]>

This patch tries to fix memcg's lru rotation sanity...make memcg use
the same logic as global LRU does.

Now, at __isolate_lru_page() retruns -EBUSY, the page is rotated to
the tail of LRU in global LRU's isolate LRU pages. But in memcg,
it's not handled. This makes memcg do the same behavior as global LRU
and rotate LRU in the page is busy.

Changelog: v1->v2
- adjusted to new beas patch.

Signed-off-by: KAMEZAWA Hiroyuki <[email protected]>

---
Index: lumpy-reclaim-trial/mm/vmscan.c
===================================================================
--- lumpy-reclaim-trial.orig/mm/vmscan.c
+++ lumpy-reclaim-trial/mm/vmscan.c
@@ -844,7 +844,6 @@ int __isolate_lru_page(struct page *page
*/
ClearPageLRU(page);
ret = 0;
- mem_cgroup_del_lru(page);
}

return ret;
@@ -892,12 +891,14 @@ static unsigned long isolate_lru_pages(u
switch (__isolate_lru_page(page, mode, file)) {
case 0:
list_move(&page->lru, dst);
+ mem_cgroup_del_lru(page);
nr_taken++;
break;

case -EBUSY:
/* else it is being freed elsewhere */
list_move(&page->lru, src);
+ mem_cgroup_rotate_lru_list(page, page_lru(page));
continue;

default:
@@ -938,6 +939,7 @@ static unsigned long isolate_lru_pages(u
continue;
if (__isolate_lru_page(cursor_page, mode, file) == 0) {
list_move(&cursor_page->lru, dst);
+ mem_cgroup_del_lru(page);
nr_taken++;
scan++;
}
Index: lumpy-reclaim-trial/mm/memcontrol.c
===================================================================
--- lumpy-reclaim-trial.orig/mm/memcontrol.c
+++ lumpy-reclaim-trial/mm/memcontrol.c
@@ -649,6 +649,7 @@ unsigned long mem_cgroup_isolate_pages(u
int zid = zone_idx(z);
struct mem_cgroup_per_zone *mz;
int lru = LRU_FILE * !!file + !!active;
+ int ret;

BUG_ON(!mem_cont);
mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
@@ -666,9 +667,19 @@ unsigned long mem_cgroup_isolate_pages(u
continue;

scan++;
- if (__isolate_lru_page(page, mode, file) == 0) {
+ ret = __isolate_lru_page(page, mode, file);
+ switch (ret) {
+ case 0:
list_move(&page->lru, dst);
+ mem_cgroup_del_lru(page);
nr_taken++;
+ break;
+ case -EBUSY:
+ /* we don't affect global LRU but rotate in our LRU */
+ mem_cgroup_rotate_lru_list(page, page_lru(page));
+ break;
+ default:
+ break;
}
}

2009-06-12 03:09:16

by Daisuke Nishimura

[permalink] [raw]
Subject: Re: [BUGFIX][PATCH] memcg fix lru rotation in isolate_pages v2

On Fri, 12 Jun 2009 10:28:21 +0900, KAMEZAWA Hiroyuki <[email protected]> wrote:
> From: KAMEZAWA Hiroyuki <[email protected]>
>
> This patch tries to fix memcg's lru rotation sanity...make memcg use
> the same logic as global LRU does.
>
> Now, at __isolate_lru_page() retruns -EBUSY, the page is rotated to
> the tail of LRU in global LRU's isolate LRU pages. But in memcg,
> it's not handled. This makes memcg do the same behavior as global LRU
> and rotate LRU in the page is busy.
>
> Changelog: v1->v2
> - adjusted to new beas patch.
>
> Signed-off-by: KAMEZAWA Hiroyuki <[email protected]>
>
Looks good to me.

Reviewed-by: Daisuke Nishimura <[email protected]>

> ---
> Index: lumpy-reclaim-trial/mm/vmscan.c
> ===================================================================
> --- lumpy-reclaim-trial.orig/mm/vmscan.c
> +++ lumpy-reclaim-trial/mm/vmscan.c
> @@ -844,7 +844,6 @@ int __isolate_lru_page(struct page *page
> */
> ClearPageLRU(page);
> ret = 0;
> - mem_cgroup_del_lru(page);
> }
>
> return ret;
> @@ -892,12 +891,14 @@ static unsigned long isolate_lru_pages(u
> switch (__isolate_lru_page(page, mode, file)) {
> case 0:
> list_move(&page->lru, dst);
> + mem_cgroup_del_lru(page);
> nr_taken++;
> break;
>
> case -EBUSY:
> /* else it is being freed elsewhere */
> list_move(&page->lru, src);
> + mem_cgroup_rotate_lru_list(page, page_lru(page));
> continue;
>
> default:
> @@ -938,6 +939,7 @@ static unsigned long isolate_lru_pages(u
> continue;
> if (__isolate_lru_page(cursor_page, mode, file) == 0) {
> list_move(&cursor_page->lru, dst);
> + mem_cgroup_del_lru(page);
> nr_taken++;
> scan++;
> }
> Index: lumpy-reclaim-trial/mm/memcontrol.c
> ===================================================================
> --- lumpy-reclaim-trial.orig/mm/memcontrol.c
> +++ lumpy-reclaim-trial/mm/memcontrol.c
> @@ -649,6 +649,7 @@ unsigned long mem_cgroup_isolate_pages(u
> int zid = zone_idx(z);
> struct mem_cgroup_per_zone *mz;
> int lru = LRU_FILE * !!file + !!active;
> + int ret;
>
> BUG_ON(!mem_cont);
> mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
> @@ -666,9 +667,19 @@ unsigned long mem_cgroup_isolate_pages(u
> continue;
>
> scan++;
> - if (__isolate_lru_page(page, mode, file) == 0) {
> + ret = __isolate_lru_page(page, mode, file);
> + switch (ret) {
> + case 0:
> list_move(&page->lru, dst);
> + mem_cgroup_del_lru(page);
> nr_taken++;
> + break;
> + case -EBUSY:
> + /* we don't affect global LRU but rotate in our LRU */
> + mem_cgroup_rotate_lru_list(page, page_lru(page));
> + break;
> + default:
> + break;
> }
> }
>
>