From: Greg KH <gregkh@linuxfoundation.org>
To: SeongJae Park <sj@kernel.org>
Cc: stable@vger.kernel.org, damon@lists.linux.dev,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 6.1.y] mm/damon/reclaim: fix quota stauts loss due to online tunings
Date: Tue, 27 Feb 2024 10:19:41 +0100 [thread overview]
Message-ID: <2024022731-varying-underpaid-c855@gregkh> (raw)
In-Reply-To: <20240227051335.168121-1-sj@kernel.org>
On Mon, Feb 26, 2024 at 09:13:35PM -0800, SeongJae Park wrote:
> Patch series "mm/damon: fix quota status loss due to online tunings".
>
> DAMON_RECLAIM and DAMON_LRU_SORT is not preserving internal quota status
> when applying new user parameters, and hence could cause temporal quota
> accuracy degradation. Fix it by preserving the status.
>
> This patch (of 2):
>
> For online parameters change, DAMON_RECLAIM creates new scheme based on
> latest values of the parameters and replaces the old scheme with the new
> one. When creating it, the internal status of the quota of the old
> scheme is not preserved. As a result, charging of the quota starts from
> zero after the online tuning. The data that collected to estimate the
> throughput of the scheme's action is also reset, and therefore the
> estimation should start from the scratch again. Because the throughput
> estimation is being used to convert the time quota to the effective size
> quota, this could result in temporal time quota inaccuracy. It would be
> recovered over time, though. In short, the quota accuracy could be
> temporarily degraded after online parameters update.
>
> Fix the problem by checking the case and copying the internal fields for
> the status.
>
> Link: https://lkml.kernel.org/r/20240216194025.9207-1-sj@kernel.org
> Link: https://lkml.kernel.org/r/20240216194025.9207-2-sj@kernel.org
> Fixes: e035c280f6df ("mm/damon/reclaim: support online inputs update")
> Signed-off-by: SeongJae Park <sj@kernel.org>
> Cc: <stable@vger.kernel.org> [5.19+]
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> (cherry picked from commit 1b0ca4e4ff10a2c8402e2cf70132c683e1c772e4)
> ---
> mm/damon/reclaim.c | 18 +++++++++++++++++-
> 1 file changed, 17 insertions(+), 1 deletion(-)
>
Now queued up, thanks.
greg k-h
prev parent reply other threads:[~2024-02-27 9:19 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <2024022643-scorn-filtrate-8677@gregkh>
2024-02-27 5:13 ` [PATCH 6.1.y] mm/damon/reclaim: fix quota stauts loss due to online tunings SeongJae Park
2024-02-27 9:19 ` Greg KH [this message]
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