Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753103Ab3JBFrk (ORCPT ); Wed, 2 Oct 2013 01:47:40 -0400 Received: from mail-pa0-f43.google.com ([209.85.220.43]:53298 "EHLO mail-pa0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752799Ab3JBFri (ORCPT ); Wed, 2 Oct 2013 01:47:38 -0400 Date: Tue, 1 Oct 2013 22:47:36 -0700 (PDT) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Andrew Morton cc: Bob Liu , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk, mgorman@suse.de, hannes@cmpxchg.org, riel@redhat.com, minchan@kernel.org, Bob Liu Subject: Re: [PATCH] mm: pagevec: cleanup: drop pvec->cold argument in all places In-Reply-To: <20130930150207.3661b5c146b6ecea84194547@linux-foundation.org> Message-ID: References: <1380357239-30102-1-git-send-email-bob.liu@oracle.com> <20130930150207.3661b5c146b6ecea84194547@linux-foundation.org> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1250 Lines: 26 On Mon, 30 Sep 2013, Andrew Morton wrote: > > Nobody uses the pvec->cold argument of pagevec and it's also unreasonable for > > pages in pagevec released as cold page, so drop the cold argument from pagevec. > > Is it unreasonable? I'd say it's unreasonable to assume that all pages > in all cases are likely to be cache-hot. Example: what if the pages > are being truncated and were found to be on the inactive LRU, > unreferenced? > > A useful exercise would be to go through all those pagevec_init() sites > and convince ourselves that the decision at each place was the correct > one. > Agreed, and the "cold" argument to release_pages() becomes a no-op if this patch is merged meaning that anything released through it will automatically go to the start of the pcp lists. If the pages aren't hot then this is exactly the opposite of what we wanted to do; the fact that the pvec length doesn't take into account the size of cpu cache can almost guarantee that everything isn't cache hot. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/