From: Rik van Riel <riel@redhat.com>
To: Gleb Natapov <gleb@redhat.com>
Cc: avi@redhat.com, mtosatti@redhat.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>,
Hugh Dickins <hughd@google.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 1/2] Allow GUP to fail instead of waiting on a page.
Date: Tue, 01 Feb 2011 11:48:20 -0500 [thread overview]
Message-ID: <4D483954.20600@redhat.com> (raw)
In-Reply-To: <1296559307-14637-2-git-send-email-gleb@redhat.com>
On 02/01/2011 06:21 AM, Gleb Natapov wrote:
> GUP user may want to try to acquire a reference to a page if it is already
> in memory, but not if IO, to bring it in, is needed. For example KVM may
> tell vcpu to schedule another guest process if current one is trying to
> access swapped out page. Meanwhile, the page will be swapped in and the
> guest process, that depends on it, will be able to run again.
>
> This patch adds FAULT_FLAG_RETRY_NOWAIT (suggested by Linus) and
> FOLL_NOWAIT follow_page flags. FAULT_FLAG_RETRY_NOWAIT, when used in
> conjunction with VM_FAULT_ALLOW_RETRY, indicates to handle_mm_fault that
> it shouldn't drop mmap_sem and wait on a page, but return VM_FAULT_RETRY
> instead.
>
> Signed-off-by: Gleb Natapov<gleb@redhat.com>
> CC: Linus Torvalds<torvalds@linux-foundation.org>
> CC: Rik van Riel<riel@redhat.com>
> CC: Hugh Dickins<hughd@google.com>
> CC: Andrew Morton<akpm@linux-foundation.org>
Acked-by: Rik van Riel <riel@redhat.com>
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next prev parent reply other threads:[~2011-02-01 16:48 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-01 11:21 [PATCH 0/2] KVM: enable asynchronous page faults Gleb Natapov
2011-02-01 11:21 ` [PATCH 1/2] Allow GUP to fail instead of waiting on a page Gleb Natapov
2011-02-01 16:48 ` Rik van Riel [this message]
2011-02-02 0:42 ` Andrew Morton
2011-02-02 13:31 ` Gleb Natapov
2011-02-02 19:37 ` Andrew Morton
2011-02-01 11:21 ` [PATCH 2/2] KVM: Enable async page fault processing Gleb Natapov
2011-02-22 8:38 ` Lai Jiangshan
2011-03-24 12:22 ` Gleb Natapov
2011-03-24 13:23 ` Avi Kivity
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