From 3a9bb7b1879bef057a5dbff1dac1fa1411638064 Mon Sep 17 00:00:00 2001 From: Yang Yang Date: Mon, 15 Aug 2022 07:28:37 +0000 Subject: [PATCH] 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 aae466b0052e ("mm/swap: implement workingset detection for anonymous LRU") Link: https://lkml.kernel.org/r/20220815072835.74876-1-yang.yang29@zte.com.cn Signed-off-by: Yang Yang Signed-off-by: CGEL ZTE Reviewed-by: Ran Xiaokai Reviewed-by: wangyong Cc: Joonsoo Kim Signed-off-by: Andrew Morton --- mm/page_io.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/mm/page_io.c b/mm/page_io.c index 68d53fc27598..fc6b3fb1f7c5 100644 --- a/mm/page_io.c +++ b/mm/page_io.c @@ -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; }