From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: Peter Chen <hzpeterchen@gmail.com>
Cc: Michal Nazarewicz <mina86@mina86.com>,
peter.chen@nxp.com, fugang.duan@nxp.com,
linux-usb@vger.kernel.org, lkml <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org,
Marek Szyprowski <m.szyprowski@samsung.com>
Subject: Re: Why CMA allocater fails if there is a signal pending?
Date: Mon, 25 Mar 2019 10:26:33 +0000 [thread overview]
Message-ID: <20190325102633.v6hkvda6q7462wza@shell.armlinux.org.uk> (raw)
In-Reply-To: <CAL411-pwHq4Df-FsBu=Vzd4CR6Pzee2yR579hHeZuh8T7fBNJA@mail.gmail.com>
On Mon, Mar 25, 2019 at 04:37:09PM +0800, Peter Chen wrote:
> Hi Michal & Marek,
>
> I meet an issue that the DMA (CMA used) allocation failed if there is a user
> signal, Eg Ctrl+C, it causes the USB xHCI stack fails to resume due to
> dma_alloc_coherent
> failed. It can be easy to reproduce if the user press Ctrl+C at
> suspend/resume test.
It has been possible in the past for cma_alloc() to take seconds or
longer to allocate, depending on the size of the CMA area and the
number of pinned GFP_MOVABLE pages within the CMA area. Whether that
is true of today's CMA or not, I don't know.
It's probably there to allow such a situation to be recoverable, but
is not a good idea if we're expecting dma_alloc_*() not to fail in
those scenarios.
--
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next prev parent reply other threads:[~2019-03-25 10:26 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-25 8:37 Peter Chen
2019-03-25 10:26 ` Russell King - ARM Linux admin [this message]
2019-03-25 16:44 ` Florian Fainelli
2019-03-25 17:43 ` Russell King - ARM Linux admin
2019-03-26 2:21 ` Peter Chen
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