From: Doug Ledford <dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
To: Roland Dreier <roland-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
Yishai Hadas <yishaih-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
Cc: linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH] IB/mlx4: Allocation of CQ resize structure doesn't need to be atomic
Date: Tue, 02 Aug 2016 13:52:56 -0400 [thread overview]
Message-ID: <1470160376.18081.25.camel@redhat.com> (raw)
In-Reply-To: <1469768323-8093-1-git-send-email-roland-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
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On Thu, 2016-07-28 at 21:58 -0700, Roland Dreier wrote:
> From: Roland Dreier <roland-BHEL68pLQRGGvPXPguhicg@public.gmane.org>
>
> We allocate a small tracking structure as part of
> mlx4_ib_resize_cq().
> However, we don't need to use GFP_ATOMIC -- immediately after the
> allocation, we call mlx4_cq_resize(), which allocates a command
> mailbox with GFP_KERNEL and then sleeps on a firmware command, so we
> better not be in an atomic context.
>
> This actually has a real impact, because when this GFP_ATOMIC
> allocation fails (and GFP_ATOMIC does fail in practice) then a
> userspace consumer resizing a CQ will get a spurious failure that we
> can easily avoid.
>
> Signed-off-by: Roland Dreier <roland-BHEL68pLQRGGvPXPguhicg@public.gmane.org>
>
Thanks, I reworded the commit subject for length and applied.
--
Doug Ledford <dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
GPG KeyID: 0E572FDD
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prev parent reply other threads:[~2016-08-02 17:52 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-29 4:58 [PATCH] IB/mlx4: Allocation of CQ resize structure doesn't need to be atomic Roland Dreier
[not found] ` <1469768323-8093-1-git-send-email-roland-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2016-07-31 6:42 ` Leon Romanovsky
2016-08-02 17:52 ` Doug Ledford [this message]
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