From: Ming Lei <ming.lei@redhat.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>,
David Gibson <david@gibson.dropbear.id.au>,
"Darrick J. Wong" <darrick.wong@oracle.com>,
linux-block@vger.kernel.org, linux-xfs@vger.kernel.org
Subject: Re: alternative take on the same page merging leak fix
Date: Wed, 12 Jun 2019 09:09:23 +0800 [thread overview]
Message-ID: <20190612010922.GA17522@ming.t460p> (raw)
In-Reply-To: <20190611151007.13625-1-hch@lst.de>
Hi Christoph,
On Tue, Jun 11, 2019 at 05:10:02PM +0200, Christoph Hellwig wrote:
> Hi Jens, hi Ming,
>
> this is the tested and split version of what I think is the better
> fix for the get_user_pages page leak, as it leaves the intelligence
> in the callers instead of in bio_try_to_merge_page.
I am fine with either one from upstream developer view, so let Jens
decide.
However:
We have to backport the fixes to -stable tree, and downstream need to
ship the fix too.
The issue is quite serious because the leak is in IO path and the whole
system ram can be used up easily on some workloads. So I think the fix
should be for 5.2, however, regression risk might be increased by
pulling cleanup & re-factor in now.
I really appreciate you may cook a fix-only patch for this issue.
Especially the change in add pc page code isn't necessary for fixing
the issue.
Thanks,
Ming
next prev parent reply other threads:[~2019-06-12 1:09 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-11 15:10 alternative take on the same page merging leak fix Christoph Hellwig
2019-06-11 15:10 ` [PATCH 1/5] block: fix gap checking in __bio_add_pc_page Christoph Hellwig
2019-06-11 15:10 ` [PATCH 2/5] block: factor out a bio_try_merge_pc_page helper Christoph Hellwig
2019-06-11 15:10 ` [PATCH 3/5] block: return from __bio_try_merge_page if merging occured in the same page Christoph Hellwig
2019-06-12 10:14 ` Ming Lei
2019-06-11 15:10 ` [PATCH 4/5] block: fix page leak when merging to " Christoph Hellwig
2019-06-12 10:18 ` Ming Lei
2019-06-11 15:10 ` [PATCH 5/5] block: use __bio_try_merge_page in __bio_try_merge_pc_page Christoph Hellwig
2019-06-12 1:09 ` Ming Lei [this message]
2019-06-12 7:45 ` alternative take on the same page merging leak fix Christoph Hellwig
2019-06-12 10:11 ` Ming Lei
2019-06-13 9:02 ` Jens Axboe
2019-06-13 9:02 ` Christoph Hellwig
2019-06-13 9:11 ` Jens Axboe
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