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From: Andrew Morton <akpm@linux-foundation.org>
To: Jaewon Kim <jaewon31.kim@samsung.com>
Cc: sj@kernel.org, minchan@kernel.org, vbabka@suse.cz,
	kaleshsingh@google.com, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, jaewon31.kim@gmail.com
Subject: Re: [PATCH] vmscan: add a vmscan event for reclaim_pages
Date: Wed, 9 Oct 2024 13:49:00 -0700	[thread overview]
Message-ID: <20241009134900.7cd8fe9000a9fafd7ca1c592@linux-foundation.org> (raw)
In-Reply-To: <20241009093124.3647359-1-jaewon31.kim@samsung.com>

On Wed,  9 Oct 2024 18:31:24 +0900 Jaewon Kim <jaewon31.kim@samsung.com> wrote:

> The reclaim_folio_list uses a dummy reclaim_stat and is not being
> used. To know the memory stat, add a new trace event. This is useful how
> how many pages are not reclaimed or why.
> 
> This is an example.
> mm_vmscan_reclaim_pages: nr_scanned=17 nr_reclaimed=17 nr_dirty=0 nr_writeback=0 nr_congested=0 nr_immediate=0 nr_activate_anon=0 nr_activate_file=0 nr_ref_keep=0 nr_unmap_fail=0
> 
> Currenlty reclaim_folio_list is only called by reclaim_pages, and
> reclaim_pages is used by damon and madvise. In the latest Android,
> reclaim_pages is also used by shmem to reclaim all pages in a
> address_space.
> 

This looks like it will add some overhead when tracing has been
enabled.  Has this been measured and is it significant?

Also, we're adding a significant amount of code for a simple trace
record.  Do others think this is justifiable?


  reply	other threads:[~2024-10-09 20:49 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20241009093133epcas1p39b770ebcc6d2d78cad2f9a522bc6f179@epcas1p3.samsung.com>
2024-10-09  9:31 ` Jaewon Kim
2024-10-09 20:49   ` Andrew Morton [this message]
     [not found]   ` <CGME20241009093133epcas1p39b770ebcc6d2d78cad2f9a522bc6f179@epcms1p6>
2024-10-09 23:53     ` Jaewon Kim
2024-10-11  8:25     ` Jaewon Kim
2024-10-11  8:55       ` Vlastimil Babka
     [not found]       ` <CGME20241009093133epcas1p39b770ebcc6d2d78cad2f9a522bc6f179@epcms1p4>
2024-10-11 11:39         ` Jaewon Kim
2024-10-10  8:28   ` Vlastimil Babka
     [not found]   ` <CGME20241009093133epcas1p39b770ebcc6d2d78cad2f9a522bc6f179@epcms1p1>
2024-10-11  8:22     ` 김재원

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