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From: Andrea Arcangeli <aarcange@redhat.com>
To: Chen Gang <xili_gchen_5257@hotmail.com>
Cc: Richard Weinberger <richard.weinberger@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	"kirill.shutemov@linux.intel.com"
	<kirill.shutemov@linux.intel.com>,
	"riel@redhat.com" <riel@redhat.com>,
	Michal Hocko <mhocko@suse.cz>,
	"oleg@redhat.com" <oleg@redhat.com>,
	"asha.levin@oracle.com" <asha.levin@oracle.com>,
	"pfeiner@google.com" <pfeiner@google.com>,
	"vishnu.ps@samsung.com" <vishnu.ps@samsung.com>,
	Linux Memory <linux-mm@kvack.org>,
	kernel mailing list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm/mmap.c: Remove redundant vma looping
Date: Sun, 4 Oct 2015 19:26:45 +0200	[thread overview]
Message-ID: <20151004172645.GO19466@redhat.com> (raw)
In-Reply-To: <BLU436-SMTP233624CAE8A4C054B5DFFF8B9490@phx.gbl>

Hello Chen,

On Sun, Oct 04, 2015 at 12:55:29PM +0800, Chen Gang wrote:
> Theoretically, the lock and unlock need to be symmetric, if we have to
> lock f_mapping all firstly, then lock all anon_vma, probably, we also
> need to unlock anon_vma all, then unlock all f_mapping.

They don't need to be symmetric because the unlocking order doesn't
matter. To avoid lock inversion deadlocks it is enough to enforce the
lock order.

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  reply	other threads:[~2015-10-04 17:26 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-03 19:38 [PATCH] mm/mmap.c: Remove redundant vma looping Chen Gang
2015-10-03 20:09 ` Richard Weinberger
2015-10-04  4:55   ` Chen Gang
2015-10-04 17:26     ` Andrea Arcangeli [this message]
2015-10-05 12:23       ` Chen Gang

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