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Date: Tue, 26 Nov 2013 11:20:53 +0100
From: Peter Zijlstra <peterz@infradead.org>
Subject: Re: [patch 6/9] mm + fs: store shadow entries in page cache
Message-ID: <20131126102053.GJ10022@twins.programming.kicks-ass.net>
References: <1385336308-27121-1-git-send-email-hannes@cmpxchg.org>
 <1385336308-27121-7-git-send-email-hannes@cmpxchg.org>
 <20131125231716.GJ8803@dastard>
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Sender: owner-linux-mm@kvack.org
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To: Dave Chinner <david@fromorbit.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>, Andrew Morton <akpm@linux-foundation.org>, Rik van Riel <riel@redhat.com>, Jan Kara <jack@suse.cz>, Vlastimil Babka <vbabka@suse.cz>, Tejun Heo <tj@kernel.org>, Andi Kleen <andi@firstfloor.org>, Andrea Arcangeli <aarcange@redhat.com>, Greg Thelen <gthelen@google.com>, Christoph Hellwig <hch@infradead.org>, Hugh Dickins <hughd@google.com>, KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>, Mel Gorman <mgorman@suse.de>, Minchan Kim <minchan.kim@gmail.com>, Michel Lespinasse <walken@google.com>, Seth Jennings <sjenning@linux.vnet.ibm.com>, Roman Gushchin <klamm@yandex-team.ru>, Ozgun Erdogan <ozgun@citusdata.com>, Metin Doslu <metin@citusdata.com>, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org

On Tue, Nov 26, 2013 at 10:17:16AM +1100, Dave Chinner wrote:
> void truncate_inode_pages_final(struct address_space *mapping)
> {
> 	mapping_set_exiting(mapping);
> 	if (inode->i_data.nrpages || inode->i_data.nrshadows) {
> 		/*
> 		 * spinlock barrier to ensure all modifications are
> 		 * complete before we do the final truncate
> 		 */
> 		spin_lock_irq(&mapping->tree_lock);
> 		spin_unlock_irq(&mapping->tree_lock);

	spin_unlock_wait() ?

Its cheaper, but prone to starvation; its typically useful when you're
waiting for the last owner to go away and know there won't be any new
ones around.

> 		truncate_inode_pages_range(mapping, 0, (loff_t)-1);
> }

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