From mboxrd@z Thu Jan  1 00:00:00 1970
From: Dave Hansen <dave@sr71.net>
Subject: Re: [PATCH 5/8] thp, mm: locking tail page is a bug
Date: Wed, 17 Jul 2013 15:43:53 -0700
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References: <1373885274-25249-1-git-send-email-kirill.shutemov@linux.intel.com> <1373885274-25249-6-git-send-email-kirill.shutemov@linux.intel.com> <20130717140953.7560e88e607f8f5df1b1fdd8@linux-foundation.org>
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Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
 Andrea Arcangeli <aarcange@redhat.com>,
 Al Viro <viro@zeniv.linux.org.uk>, Hugh Dickins <hughd@google.com>,
 Wu Fengguang <fengguang.wu@intel.com>,
 Jan Kara <jack@suse.cz>, Mel Gorman <mgorman@suse.de>,
 linux-mm@kvack.org, Andi Kleen <ak@linux.intel.com>,
 Matthew Wilcox <willy@linux.intel.com>,
 "Kirill A. Shutemov" <kirill@shutemov.name>,
 Hillf Danton <dhillf@gmail.com>,
 linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
To: Andrew Morton <akpm@linux-foundation.org>
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On 07/17/2013 02:09 PM, Andrew Morton wrote:
> lock_page() is a pretty commonly called function, and I assume quite a
> lot of people run with CONFIG_DEBUG_VM=y.
> 
> Is the overhead added by this patch really worthwhile?

I always thought of it as a developer-only thing.  I don't think any of
the big distros turn it on by default.

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Date: Wed, 17 Jul 2013 15:43:53 -0700
From: Dave Hansen <dave@sr71.net>
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To: Andrew Morton <akpm@linux-foundation.org>
CC: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Al Viro <viro@zeniv.linux.org.uk>, Hugh Dickins <hughd@google.com>,
        Wu Fengguang <fengguang.wu@intel.com>, Jan Kara <jack@suse.cz>,
        Mel Gorman <mgorman@suse.de>, linux-mm@kvack.org,
        Andi Kleen <ak@linux.intel.com>,
        Matthew Wilcox <willy@linux.intel.com>,
        "Kirill A. Shutemov" <kirill@shutemov.name>,
        Hillf Danton <dhillf@gmail.com>, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 5/8] thp, mm: locking tail page is a bug
References: <1373885274-25249-1-git-send-email-kirill.shutemov@linux.intel.com> <1373885274-25249-6-git-send-email-kirill.shutemov@linux.intel.com> <20130717140953.7560e88e607f8f5df1b1fdd8@linux-foundation.org>
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On 07/17/2013 02:09 PM, Andrew Morton wrote:
> lock_page() is a pretty commonly called function, and I assume quite a
> lot of people run with CONFIG_DEBUG_VM=y.
> 
> Is the overhead added by this patch really worthwhile?

I always thought of it as a developer-only thing.  I don't think any of
the big distros turn it on by default.