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From: Chris Wilson <chris@chris-wilson.co.uk>
To: Roman Peniaev <r.peniaev@gmail.com>
Cc: intel-gfx@lists.freedesktop.org,
	Andrew Morton <akpm@linux-foundation.org>,
	David Rientjes <rientjes@google.com>,
	Mel Gorman <mgorman@techsingularity.net>,
	linux-mm@kvack.org,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] mm/vmap: Add a notifier for when we run out of vmap address space
Date: Thu, 17 Mar 2016 12:57:36 +0000	[thread overview]
Message-ID: <20160317125736.GT14143@nuc-i3427.alporthouse.com> (raw)
In-Reply-To: <CACZ9PQX+E2LscOGyVQ4xZNK3qdYYotq4HiyGc8o+YwoNi-w1Hg@mail.gmail.com>

On Thu, Mar 17, 2016 at 01:37:06PM +0100, Roman Peniaev wrote:
> > +       freed = 0;
> > +       blocking_notifier_call_chain(&vmap_notify_list, 0, &freed);
> 
> It seems to me that alloc_vmap_area() was designed not to sleep,
> at least on GFP_NOWAIT path (__GFP_DIRECT_RECLAIM is not set).
> 
> But blocking_notifier_call_chain() might sleep.

Indeed, I had not anticipated anybody using GFP_ATOMIC or equivalently
restrictive gfp_t for vmap and yes there are such callers.

Would guarding the notifier with gfp & __GFP_DIRECT_RECLAIM and
!(gfp & __GFP_NORETRY) == be sufficient? Is that enough for GFP_NOFS?
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre

WARNING: multiple messages have this Message-ID (diff)
From: Chris Wilson <chris@chris-wilson.co.uk>
To: Roman Peniaev <r.peniaev@gmail.com>
Cc: intel-gfx@lists.freedesktop.org,
	Andrew Morton <akpm@linux-foundation.org>,
	David Rientjes <rientjes@google.com>,
	Mel Gorman <mgorman@techsingularity.net>,
	linux-mm@kvack.org,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] mm/vmap: Add a notifier for when we run out of vmap address space
Date: Thu, 17 Mar 2016 12:57:36 +0000	[thread overview]
Message-ID: <20160317125736.GT14143@nuc-i3427.alporthouse.com> (raw)
In-Reply-To: <CACZ9PQX+E2LscOGyVQ4xZNK3qdYYotq4HiyGc8o+YwoNi-w1Hg@mail.gmail.com>

On Thu, Mar 17, 2016 at 01:37:06PM +0100, Roman Peniaev wrote:
> > +       freed = 0;
> > +       blocking_notifier_call_chain(&vmap_notify_list, 0, &freed);
> 
> It seems to me that alloc_vmap_area() was designed not to sleep,
> at least on GFP_NOWAIT path (__GFP_DIRECT_RECLAIM is not set).
> 
> But blocking_notifier_call_chain() might sleep.

Indeed, I had not anticipated anybody using GFP_ATOMIC or equivalently
restrictive gfp_t for vmap and yes there are such callers.

Would guarding the notifier with gfp & __GFP_DIRECT_RECLAIM and
!(gfp & __GFP_NORETRY) == be sufficient? Is that enough for GFP_NOFS?
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre

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  reply	other threads:[~2016-03-17 13:25 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-17 11:59 [PATCH 1/2] mm/vmap: Add a notifier for when we run out of vmap address space Chris Wilson
2016-03-17 11:59 ` Chris Wilson
2016-03-17 11:59 ` Chris Wilson
2016-03-17 11:59 ` [PATCH 2/2] drm/i915/shrinker: Hook up vmap allocation failure notifier Chris Wilson
2016-03-17 11:59   ` Chris Wilson
2016-03-17 12:37 ` [PATCH 1/2] mm/vmap: Add a notifier for when we run out of vmap address space Roman Peniaev
2016-03-17 12:37   ` Roman Peniaev
2016-03-17 12:57   ` Chris Wilson [this message]
2016-03-17 12:57     ` Chris Wilson
2016-03-17 13:21     ` Roman Peniaev
2016-03-17 13:21       ` Roman Peniaev
2016-03-17 13:30       ` Chris Wilson
2016-03-17 13:30         ` Chris Wilson
2016-03-17 13:34 ` [PATCH v2] " Chris Wilson
2016-03-17 13:34   ` Chris Wilson
2016-03-17 13:34   ` Chris Wilson
2016-03-17 13:41   ` Chris Wilson
2016-03-17 13:41     ` Chris Wilson
2016-03-28 23:15     ` Andrew Morton
2016-03-28 23:15       ` Andrew Morton
2016-03-29  8:16       ` [PATCH v3] " Chris Wilson
2016-03-29  8:16         ` Chris Wilson
2016-03-29  8:16         ` Chris Wilson
2016-03-18  7:03 ` ✗ Fi.CI.BAT: failure for series starting with [v2] mm/vmap: Add a notifier for when we run out of vmap address space (rev2) Patchwork
2016-03-29  8:34 ` ✗ Fi.CI.BAT: failure for series starting with [v3] mm/vmap: Add a notifier for when we run out of vmap address space (rev3) Patchwork
2016-03-29 12:51   ` Marius Vlad
2016-03-29 12:56     ` Chris Wilson

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