Commit 3a9bb7b1 authored by Yang Yang's avatar Yang Yang Committed by Andrew Morton

mm/page_io: count submission time as thrashing delay for delayacct

Once upon a time, we only support accounting thrashing of page cache. 
Then Joonsoo introduced workingset detection for anonymous pages and we
gained the ability to account thrashing of them[1].

Likes PSI, we count submission time as thrashing delay because when the
device is congested, or the submitting cgroup IO-throttled, submission can
be a significant part of overall IO time.

Without this patch, swap thrashing through frontswap or some block
device supporting rw_page operation isn't measured correctly.

This patch is based on "delayacct: support re-entrance detection of
thrashing accounting".

[1] commit aae466b0 ("mm/swap: implement workingset detection for anonymous LRU")

Link: https://lkml.kernel.org/r/20220815072835.74876-1-yang.yang29@zte.com.cnSigned-off-by: default avatarYang Yang <yang.yang29@zte.com.cn>
Signed-off-by: default avatarCGEL ZTE <cgel.zte@gmail.com>
Reviewed-by: default avatarRan Xiaokai <ran.xiaokai@zte.com.cn>
Reviewed-by: default avatarwangyong <wang.yong12@zte.com.cn>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent aa1cf99b
......@@ -452,18 +452,21 @@ int swap_readpage(struct page *page, bool synchronous,
struct swap_info_struct *sis = page_swap_info(page);
bool workingset = PageWorkingset(page);
unsigned long pflags;
bool in_thrashing;
VM_BUG_ON_PAGE(!PageSwapCache(page) && !synchronous, page);
VM_BUG_ON_PAGE(!PageLocked(page), page);
VM_BUG_ON_PAGE(PageUptodate(page), page);
/*
* Count submission time as memory stall. When the device is congested,
* or the submitting cgroup IO-throttled, submission can be a
* significant part of overall IO time.
* Count submission time as memory stall and delay. When the device
* is congested, or the submitting cgroup IO-throttled, submission
* can be a significant part of overall IO time.
*/
if (workingset)
if (workingset) {
delayacct_thrashing_start(&in_thrashing);
psi_memstall_enter(&pflags);
}
delayacct_swapin_start();
if (frontswap_load(page) == 0) {
......@@ -512,8 +515,10 @@ int swap_readpage(struct page *page, bool synchronous,
bio_put(bio);
out:
if (workingset)
if (workingset) {
delayacct_thrashing_end(&in_thrashing);
psi_memstall_leave(&pflags);
}
delayacct_swapin_end();
return ret;
}
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment