From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f173.google.com (mail-pd0-f173.google.com [209.85.192.173]) by kanga.kvack.org (Postfix) with ESMTP id A5BCD6B0032 for ; Tue, 31 Mar 2015 01:57:38 -0400 (EDT) Received: by pddn5 with SMTP id n5so9800237pdd.2 for ; Mon, 30 Mar 2015 22:57:38 -0700 (PDT) Received: from mail-pd0-x229.google.com (mail-pd0-x229.google.com. [2607:f8b0:400e:c02::229]) by mx.google.com with ESMTPS id ku6si8293573pab.228.2015.03.30.22.57.37 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 30 Mar 2015 22:57:37 -0700 (PDT) Received: by pdrw1 with SMTP id w1so1530910pdr.0 for ; Mon, 30 Mar 2015 22:57:37 -0700 (PDT) Date: Tue, 31 Mar 2015 14:57:29 +0900 From: Minchan Kim Subject: Re: [PATCH 3/4] mm: move lazy free pages to inactive list Message-ID: <20150331055729.GC16825@blaptop> References: <1426036838-18154-1-git-send-email-minchan@kernel.org> <1426036838-18154-3-git-send-email-minchan@kernel.org> <20150320154358.51bcf3cbceeb8fbbdb2b58e5@linux-foundation.org> <20150330053502.GB3008@blaptop> <20150330142010.5d14fbc07e05180cc3ecce5c@linux-foundation.org> <20150331044525.GB16825@blaptop> <20150330222847.f255962c.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150330222847.f255962c.akpm@linux-foundation.org> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Michal Hocko , Johannes Weiner , Mel Gorman , Rik van Riel , Shaohua Li , Yalin.Wang@sonymobile.com On Mon, Mar 30, 2015 at 10:28:47PM -0700, Andrew Morton wrote: > On Tue, 31 Mar 2015 13:45:25 +0900 Minchan Kim wrote: > > > > > > deactivate_page() doesn't look at or alter PageReferenced(). Should it? > > > > Absolutely true. Thanks. > > Here it goes. > > > > >From 2b2c92eb73a1cceac615b9abd4c0f5f0c3395ff5 Mon Sep 17 00:00:00 2001 > > From: Minchan Kim > > Date: Tue, 31 Mar 2015 13:38:46 +0900 > > Subject: [PATCH] mm: lru_deactivate_fn should clear PG_referenced > > > > deactivate_page aims for accelerate for reclaiming through > > moving pages from active list to inactive list so we should > > clear PG_referenced for the goal. > > > > ... > > > > --- a/mm/swap.c > > +++ b/mm/swap.c > > @@ -800,6 +800,7 @@ static void lru_deactivate_fn(struct page *page, struct lruvec *lruvec, > > > > del_page_from_lru_list(page, lruvec, lru + LRU_ACTIVE); > > ClearPageActive(page); > > + ClearPageReferenced(page); > > add_page_to_lru_list(page, lruvec, lru); > > > > __count_vm_event(PGDEACTIVATE); > > What if we have > > PageLRU(page) && !PageActive(page) && PageReferenced(page) > > if we really want to "accelerate the reclaim of @page" then we should > clear PG_referenced there too. The function's name is *deactivate*_page. IOW, I think it should work for only pages in active list, IMHO. > > (And what about page_referenced(page) :)) Yes, I considered it when you mentioned PG_referenced. Now, madvise_free clear out access bit of page table when the syscall is called so shrink_page_list could reclaim pages easily. Of course, we could clear access bit by page_referenced for general purpose, not only madvise_free but it would hurt performance for madvise_free so I'd like to leave it unless there is a need for the function. -- Kind regards, Minchan Kim -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org