From: Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
To: Chris Wilson <chris-Y6uKTt2uX1cEflXRtASbqLVCufUGDwFn@public.gmane.org>
Cc: intel-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org,
Joonas Lahtinen
<joonas.lahtinen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>,
iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH v3 2/2] iommu: Remove cpu-local spinlock
Date: Wed, 15 Jun 2016 14:22:23 +0200 [thread overview]
Message-ID: <20160615122223.GI26566@8bytes.org> (raw)
In-Reply-To: <1464779409-26711-2-git-send-email-chris-Y6uKTt2uX1cEflXRtASbqLVCufUGDwFn@public.gmane.org>
On Wed, Jun 01, 2016 at 12:10:09PM +0100, Chris Wilson wrote:
> By avoiding cross-CPU usage of the per-cpu iova cache, we can forgo
> having a spinlock inside the per-cpu struct. The only place where we
> actually may touch another CPU's data is when performing a cache flush
> after running out of memory. Here, we can instead schedule a task to run
> on the other CPU to do the flush before trying again.
The big benefit of the spinlock is that the rcache can be flushed from a
different cpu without the need to send IPIs to everyone.
Joerg
WARNING: multiple messages have this Message-ID (diff)
From: Joerg Roedel <joro@8bytes.org>
To: Chris Wilson <chris@chris-wilson.co.uk>
Cc: intel-gfx@lists.freedesktop.org,
Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 2/2] iommu: Remove cpu-local spinlock
Date: Wed, 15 Jun 2016 14:22:23 +0200 [thread overview]
Message-ID: <20160615122223.GI26566@8bytes.org> (raw)
In-Reply-To: <1464779409-26711-2-git-send-email-chris@chris-wilson.co.uk>
On Wed, Jun 01, 2016 at 12:10:09PM +0100, Chris Wilson wrote:
> By avoiding cross-CPU usage of the per-cpu iova cache, we can forgo
> having a spinlock inside the per-cpu struct. The only place where we
> actually may touch another CPU's data is when performing a cache flush
> after running out of memory. Here, we can instead schedule a task to run
> on the other CPU to do the flush before trying again.
The big benefit of the spinlock is that the rcache can be flushed from a
different cpu without the need to send IPIs to everyone.
Joerg
next prev parent reply other threads:[~2016-06-15 12:22 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-31 16:34 [PATCH] iommu: Disable preemption around use of this_cpu_ptr() Chris Wilson
2016-05-31 16:34 ` Chris Wilson
2016-05-31 17:04 ` ✗ Ro.CI.BAT: warning for " Patchwork
2016-06-01 10:23 ` [PATCH v2] " Chris Wilson
2016-06-01 11:10 ` [PATCH v3 1/2] " Chris Wilson
2016-06-01 11:10 ` [PATCH v3 2/2] iommu: Remove cpu-local spinlock Chris Wilson
2016-06-01 11:10 ` Chris Wilson
2016-06-01 12:40 ` Joonas Lahtinen
[not found] ` <1464779409-26711-2-git-send-email-chris-Y6uKTt2uX1cEflXRtASbqLVCufUGDwFn@public.gmane.org>
2016-06-15 12:22 ` Joerg Roedel [this message]
2016-06-15 12:22 ` Joerg Roedel
2016-06-01 12:25 ` [PATCH v3 1/2] iommu: Disable preemption around use of this_cpu_ptr() Joonas Lahtinen
2016-06-01 12:25 ` Joonas Lahtinen
2016-06-15 12:25 ` Joerg Roedel
2016-06-26 10:54 ` Thorsten Leemhuis
2016-06-27 11:19 ` Joerg Roedel
2016-06-27 11:19 ` Joerg Roedel
2016-06-27 11:14 ` Joerg Roedel
2016-06-27 11:14 ` Joerg Roedel
2016-06-01 11:00 ` ✓ Ro.CI.BAT: success for iommu: Disable preemption around use of this_cpu_ptr() (rev2) Patchwork
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