linux-kernel - [PATCH] delayacct: add memory reclaim delay in get_page_from

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Date:   Wed, 20 Sep 2023 17:38:49 +0800
From:   liwenyu <wenyuli@...bilibili.com>
To:     akpm@...ux-foundation.org
Cc:     bsingharora@...il.com, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, wangyun@...ibili.com
Subject: [PATCH] delayacct: add memory reclaim delay in get_page_from_freelist

The current memory reclaim delay statistics only count the direct memory
reclaim of the task in do_try_to_free_pages(). In systems with NUMA
open, some tasks occasionally experience slower response times, but the
total count of reclaim does not increase, using ftrace can show that
node_reclaim has occurred.

The memory reclaim occurring in get_page_from_freelist() is also due to
heavy memory load. To get the impact of tasks in memory reclaim, this
patch adds the statistics of the memory reclaim delay statistics for
__node_reclaim().

Signed-off-by: Wen Yu Li <wenyuli@...bilibili.com>
---
  mm/vmscan.c | 2 ++
  1 file changed, 2 insertions(+)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 6f13394b112e..88be3dedc584 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -8026,6 +8026,7 @@ static int __node_reclaim(struct pglist_data 
*pgdat, gfp_t gfp_mask, unsigned in

  	cond_resched();
  	psi_memstall_enter(&pflags);
+	delayacct_freepages_start();
  	fs_reclaim_acquire(sc.gfp_mask);
  	/*
  	 * We need to be able to allocate from the reserves for RECLAIM_UNMAP
@@ -8048,6 +8049,7 @@ static int __node_reclaim(struct pglist_data 
*pgdat, gfp_t gfp_mask, unsigned in
  	memalloc_noreclaim_restore(noreclaim_flag);
  	fs_reclaim_release(sc.gfp_mask);
  	psi_memstall_leave(&pflags);
+	delayacct_freepages_end();

  	trace_mm_vmscan_node_reclaim_end(sc.nr_reclaimed);

-- 
2.30.2