mm/ksm: fix ksm_pages_scanned accounting
Patch series "mm/ksm: fix some accounting problems", v3.
We encountered some abnormal ksm_pages_scanned and ksm_zero_pages during
some random tests.
1. ksm_pages_scanned unchanged even ksmd scanning has progress.
2. ksm_zero_pages maybe -1 in some rare cases.
This patch (of 2):
During testing, I found ksm_pages_scanned is unchanged although the
scan_get_next_rmap_item() did return valid rmap_item that is not NULL.
The reason is the scan_get_next_rmap_item() will return NULL after a full
scan, so ksm_do_scan() just return without accounting of the
ksm_pages_scanned.
Fix it by just putting ksm_pages_scanned accounting in that loop, and it
will be accounted more timely if that loop would last for a long time.
Link: https://lkml.kernel.org/r/20240528-b4-ksm-counters-v3-0-34bb358fdc13@linux.dev
Link: https://lkml.kernel.org/r/20240528-b4-ksm-counters-v3-1-34bb358fdc13@linux.dev
Fixes: b348b5fe2b
("mm/ksm: add pages scanned metric")
Signed-off-by: Chengming Zhou <chengming.zhou@linux.dev>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: xu xin <xu.xin16@zte.com.cn>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ran Xiaokai <ran.xiaokai@zte.com.cn>
Cc: Stefan Roesch <shr@devkernel.io>
Cc: Yang Yang <yang.yang29@zte.com.cn>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
parent
2ef3cec44c
commit
730cdc2c72
6
mm/ksm.c
6
mm/ksm.c
@ -2754,18 +2754,16 @@ static void ksm_do_scan(unsigned int scan_npages)
|
||||
{
|
||||
struct ksm_rmap_item *rmap_item;
|
||||
struct page *page;
|
||||
unsigned int npages = scan_npages;
|
||||
|
||||
while (npages-- && likely(!freezing(current))) {
|
||||
while (scan_npages-- && likely(!freezing(current))) {
|
||||
cond_resched();
|
||||
rmap_item = scan_get_next_rmap_item(&page);
|
||||
if (!rmap_item)
|
||||
return;
|
||||
cmp_and_merge_page(page, rmap_item);
|
||||
put_page(page);
|
||||
ksm_pages_scanned++;
|
||||
}
|
||||
|
||||
ksm_pages_scanned += scan_npages - npages;
|
||||
}
|
||||
|
||||
static int ksmd_should_run(void)
|
||||
|
Loading…
Reference in New Issue
Block a user