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Date: Tue, 26 Nov 2013 11:20:53 +0100
From: Peter Zijlstra <peterz@infradead.org>
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>,
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        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
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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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);
> }