From: Sasha Levin <sasha.levin@oracle.com>
To: Andrea Arcangeli <aarcange@redhat.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org
Cc: Andres Lagar-Cavilla <andreslc@google.com>,
Gleb Natapov <gleb@kernel.org>, Radim Krcmar <rkrcmar@redhat.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Rik van Riel <riel@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Mel Gorman <mgorman@suse.de>,
Andy Lutomirski <luto@amacapital.net>,
Andrew Morton <akpm@linux-foundation.org>,
Jianyu Zhan <nasa4836@gmail.com>,
Paul Cassella <cassella@cray.com>,
Hugh Dickins <hughd@google.com>,
Peter Feiner <pfeiner@google.com>,
"Dr. David Alan Gilbert" <dgilbert@redhat.com>
Subject: Re: [PATCH 3/4] mm: gup: use get_user_pages_fast and get_user_pages_unlocked
Date: Wed, 01 Oct 2014 12:54:56 -0400 [thread overview]
Message-ID: <542C31E0.5040909@oracle.com> (raw)
In-Reply-To: <1412153797-6667-4-git-send-email-aarcange@redhat.com>
Hi Andrea,
On 10/01/2014 04:56 AM, Andrea Arcangeli wrote:
> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> index 8f5330d..6606c10 100644
> --- a/mm/mempolicy.c
> +++ b/mm/mempolicy.c
> @@ -881,7 +881,7 @@ static int lookup_node(struct mm_struct *mm, unsigned long addr)
> struct page *p;
> int err;
>
> - err = get_user_pages(current, mm, addr & PAGE_MASK, 1, 0, 0, &p, NULL);
> + err = get_user_pages_fast(addr & PAGE_MASK, 1, 0, &p);
> if (err >= 0) {
> err = page_to_nid(p);
> put_page(p);
This change looks bogus. mmap_sem might get locked in do_get_mempolicy(), and with this
change we'll try locking it again in get_user_pages_fast.
Thanks,
Sasha
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next prev parent reply other threads:[~2014-10-01 16:55 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-01 8:56 [PATCH 0/4] leverage FAULT_FOLL_ALLOW_RETRY in get_user_pages Andrea Arcangeli
2014-10-01 8:56 ` [PATCH 1/4] mm: gup: add FOLL_TRIED Andrea Arcangeli
2014-10-09 10:35 ` Peter Zijlstra
2014-10-01 8:56 ` [PATCH 2/4] mm: gup: add get_user_pages_locked and get_user_pages_unlocked Andrea Arcangeli
2014-10-01 15:51 ` Peter Feiner
2014-10-01 17:06 ` Andres Lagar-Cavilla
2014-10-02 12:40 ` Andrea Arcangeli
2014-10-09 10:47 ` Peter Zijlstra
2014-10-29 16:41 ` Andrea Arcangeli
2014-10-09 10:50 ` Peter Zijlstra
2014-10-29 16:39 ` Andrea Arcangeli
2014-10-01 8:56 ` [PATCH 3/4] mm: gup: use get_user_pages_fast " Andrea Arcangeli
2014-10-01 9:10 ` Andrea Arcangeli
2014-10-01 16:54 ` Sasha Levin [this message]
2014-10-09 10:52 ` Peter Zijlstra
2014-10-12 13:24 ` Andrea Arcangeli
2014-10-01 8:56 ` [PATCH 4/4] mm: gup: use get_user_pages_unlocked within get_user_pages_fast Andrea Arcangeli
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