From: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
To: Chris Wilson <chris@chris-wilson.co.uk>, igt-dev@lists.freedesktop.org
Subject: Re: [igt-dev] [PATCH i-g-t] igt/sw_sync: Wrap threaded counter manipulation with mb
Date: Fri, 15 Jun 2018 14:00:11 +0300 [thread overview]
Message-ID: <152906041105.7952.2191979154027542088@jlahtine-desk.ger.corp.intel.com> (raw)
In-Reply-To: <20180502092807.28266-1-chris@chris-wilson.co.uk>
Quoting Chris Wilson (2018-05-02 12:28:07)
> sw_sync/sync_multi_consumer_producer was communicating between threads
> using the sw_sync ioctl and manipulating a shared volatile counter.
> However, the ioctl itself does not imply a memory barrier, and so
> different CPUs may see different states of the counter (the volatile
> making GCC perform the operation in stages making the race even more
> likely). Instead of using volatile, use locked operations to make the
> counter manipulation thread-safe.
>
> References: https://bugs.freedesktop.org/show_bug.cgi?id=106344
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Sorry, this has got buried along with the probably thousand other
patches.
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Regards, Joonas
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prev parent reply other threads:[~2018-06-15 11:00 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-02 9:28 [igt-dev] [PATCH i-g-t] igt/sw_sync: Wrap threaded counter manipulation with mb Chris Wilson
2018-05-02 15:16 ` [igt-dev] ✓ Fi.CI.BAT: success for " Patchwork
2018-05-02 19:40 ` [igt-dev] ✓ Fi.CI.IGT: " Patchwork
2018-05-03 16:55 ` [igt-dev] [PATCH i-g-t] " Joonas Lahtinen
2018-05-03 19:40 ` Chris Wilson
2018-06-15 9:07 ` Chris Wilson
2018-05-14 8:06 ` Chris Wilson
2018-06-15 11:00 ` Joonas Lahtinen [this message]
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