From: Andy Shevchenko <andy.shevchenko@gmail.com> To: Will Deacon <will.deacon@arm.com> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>, Vinod Koul <vinod.koul@intel.com>, "djbw @ fb . com" <djbw@fb.com>, "linux-kernel @ vger . kernel . org" <linux-kernel@vger.kernel.org>, "linux-arm-kernel @ lists . infradead . org" <linux-arm-kernel@lists.infradead.org>, "viresh.kumar@linaro.org" <viresh.kumar@linaro.org> Subject: Re: [PATCH] dmatest: abort transfers immediately when asked for Date: Wed, 22 May 2013 16:26:20 +0300 [thread overview] Message-ID: <CAHp75Ve=W7bNYK3Vr_xx41SCHsHtAAA1NcPK1CwetoZNsuVe1Q@mail.gmail.com> (raw) In-Reply-To: <20130522124112.GA16361@mudshark.cambridge.arm.com> On Wed, May 22, 2013 at 3:41 PM, Will Deacon <will.deacon@arm.com> wrote: > On Tue, May 21, 2013 at 06:24:15PM +0100, Andy Shevchenko wrote: >> On Tue, May 21, 2013 at 6:11 PM, Will Deacon <will.deacon@arm.com> wrote: >> > I now observe buffer verification failures in subsequent >> > test runs after an aborted run: >> >> I think the description to the commit adfa543e "dmatest: don't use >> set_freezable_with_signal()" may shed light on this. >> >> The background (if I got it correctly) is in race with done flag. So, >> we got a callback call from the DMA engine, but we don't know which >> transfer triggers it. >> I might be wrong. This is just an assumption. > > I've not managed to work out exactly what's going on, but it's certainly > something like that. In fact, I just managed to trigger a case where all but > one of the transfers is aborted, whilst the remaining one fails. Looking at > the code, I can't see how that situation comes about, since the threads are > protected with the info mutex and kthread_stop is synchronous. >> Have you ever see such behaviour on pre v3.10-rc1 kernels? (I mean >> with old dmatest module) > > No, dmatest from 3.9 is completely reliable in my experience. Yeah, I supposed that was a rhetorical question. So, have I understood correctly that if you revert the 77101ce5 ("cancel thread ...") everything is working fine / as before? -- With Best Regards, Andy Shevchenko
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From: andy.shevchenko@gmail.com (Andy Shevchenko) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH] dmatest: abort transfers immediately when asked for Date: Wed, 22 May 2013 16:26:20 +0300 [thread overview] Message-ID: <CAHp75Ve=W7bNYK3Vr_xx41SCHsHtAAA1NcPK1CwetoZNsuVe1Q@mail.gmail.com> (raw) In-Reply-To: <20130522124112.GA16361@mudshark.cambridge.arm.com> On Wed, May 22, 2013 at 3:41 PM, Will Deacon <will.deacon@arm.com> wrote: > On Tue, May 21, 2013 at 06:24:15PM +0100, Andy Shevchenko wrote: >> On Tue, May 21, 2013 at 6:11 PM, Will Deacon <will.deacon@arm.com> wrote: >> > I now observe buffer verification failures in subsequent >> > test runs after an aborted run: >> >> I think the description to the commit adfa543e "dmatest: don't use >> set_freezable_with_signal()" may shed light on this. >> >> The background (if I got it correctly) is in race with done flag. So, >> we got a callback call from the DMA engine, but we don't know which >> transfer triggers it. >> I might be wrong. This is just an assumption. > > I've not managed to work out exactly what's going on, but it's certainly > something like that. In fact, I just managed to trigger a case where all but > one of the transfers is aborted, whilst the remaining one fails. Looking at > the code, I can't see how that situation comes about, since the threads are > protected with the info mutex and kthread_stop is synchronous. >> Have you ever see such behaviour on pre v3.10-rc1 kernels? (I mean >> with old dmatest module) > > No, dmatest from 3.9 is completely reliable in my experience. Yeah, I supposed that was a rhetorical question. So, have I understood correctly that if you revert the 77101ce5 ("cancel thread ...") everything is working fine / as before? -- With Best Regards, Andy Shevchenko
next prev parent reply other threads:[~2013-05-22 13:26 UTC|newest] Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top 2013-05-15 15:28 dmatest regression in 3.10-rc1 Will Deacon 2013-05-15 15:28 ` Will Deacon 2013-05-16 15:35 ` Will Deacon 2013-05-16 15:35 ` Will Deacon 2013-05-17 12:34 ` Vinod Koul 2013-05-17 12:34 ` Vinod Koul 2013-05-17 14:18 ` Will Deacon 2013-05-17 14:18 ` Will Deacon 2013-05-20 7:52 ` Andy Shevchenko 2013-05-20 7:52 ` Andy Shevchenko 2013-05-20 9:58 ` Will Deacon 2013-05-20 9:58 ` Will Deacon 2013-05-21 12:31 ` Andy Shevchenko 2013-05-21 12:31 ` Andy Shevchenko 2013-05-21 12:33 ` [PATCH] dmatest: abort transfers immediately when asked for Andy Shevchenko 2013-05-21 12:33 ` Andy Shevchenko 2013-05-21 15:11 ` Will Deacon 2013-05-21 15:11 ` Will Deacon 2013-05-21 17:24 ` Andy Shevchenko 2013-05-21 17:24 ` Andy Shevchenko 2013-05-22 12:41 ` Will Deacon 2013-05-22 12:41 ` Will Deacon 2013-05-22 13:26 ` Andy Shevchenko [this message] 2013-05-22 13:26 ` Andy Shevchenko 2013-05-23 10:09 ` Vinod Koul 2013-05-23 10:09 ` Vinod Koul 2013-05-23 10:51 ` Andy Shevchenko 2013-05-23 10:51 ` Andy Shevchenko 2013-05-23 10:22 ` Vinod Koul 2013-05-23 10:22 ` Vinod Koul
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