From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f46.google.com (mail-wm0-f46.google.com [74.125.82.46]) by kanga.kvack.org (Postfix) with ESMTP id 0FE28828DF for ; Thu, 28 Jan 2016 20:56:01 -0500 (EST) Received: by mail-wm0-f46.google.com with SMTP id r129so49428972wmr.0 for ; Thu, 28 Jan 2016 17:56:01 -0800 (PST) Received: from gum.cmpxchg.org (gum.cmpxchg.org. [85.214.110.215]) by mx.google.com with ESMTPS id f193si7817944wmd.24.2016.01.28.17.55.59 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 28 Jan 2016 17:56:00 -0800 (PST) Date: Thu, 28 Jan 2016 20:55:34 -0500 From: Johannes Weiner Subject: Re: computing drop-able caches Message-ID: <20160129015534.GA6401@cmpxchg.org> References: <56AAA77D.7090000@cisco.com> <20160128235815.GA5953@cmpxchg.org> <56AABA79.3030103@cisco.com> <56AAC085.9060509@cisco.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <56AAC085.9060509@cisco.com> Sender: owner-linux-mm@kvack.org List-ID: To: Daniel Walker Cc: Alexander Viro , Michal Hocko , Andrew Morton , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, "Khalid Mughal (khalidm)" , "xe-kernel@external.cisco.com" , Rik van Riel On Thu, Jan 28, 2016 at 05:29:41PM -0800, Daniel Walker wrote: > On 01/28/2016 05:03 PM, Daniel Walker wrote: > [regarding MemAvaiable] > > This new metric purportedly helps usrespace assess available memory. But, > its again based on heuristic, it takes 1/2 of page cache as reclaimable.. No, it takes the smaller value of cache/2 and the low watermark, which is a fraction of memory. Actually, that does look a little weird. Rik? We don't age cache without memory pressure, you don't know how much is used until you start taking some away. Heuristics is all we can offer. -- 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