From: Johannes Weiner <hannes@cmpxchg.org>
To: Minchan Kim <minchan@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Sahkeel Butt <shakeelb@google.com>,
Minchan Kim <minchan@google.com>
Subject: Re: [PATCH] mm: annotate refault stalls from swap_readpage
Date: Thu, 10 Oct 2019 15:17:47 -0400 [thread overview]
Message-ID: <20191010191747.GA31673@cmpxchg.org> (raw)
In-Reply-To: <20191010152134.38545-1-minchan@kernel.org>
On Thu, Oct 10, 2019 at 08:21:34AM -0700, Minchan Kim wrote:
> From: Minchan Kim <minchan@google.com>
>
> If block device supports rw_page operation, it doesn't submit bio
> so annotation in submit_bio for refault stall doesn't work.
> It happens with zram in android, especially swap read path which
> could consume CPU cycle for decompress. It is also a problem for
> zswap which uses frontswap.
>
> Annotate swap_readpage() to account the synchronous IO overhead
> to prevent underreport memory pressure.
>
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> Signed-off-by: Minchan Kim <minchan@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Can you please add a comment to the caller? Lifted from submit_bio():
/*
* 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.
*/
next prev parent reply other threads:[~2019-10-10 19:17 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-10 15:21 [PATCH] mm: annotate refault stalls from swap_readpage Minchan Kim
2019-10-10 19:17 ` Johannes Weiner [this message]
2019-10-10 22:11 ` Minchan Kim
2019-10-11 17:32 ` Shakeel Butt
2019-10-11 21:32 ` Andrew Morton
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