From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from newsguy.com (thparkth@localhost [127.0.0.1]) by newsguy.com (8.12.9/8.12.8) with ESMTP id i4CJIusG095495 for ; Wed, 12 May 2004 12:18:59 -0700 (PDT) (envelope-from thparkth@newsguy.com) Received: (from thparkth@localhost) by newsguy.com (8.12.9/8.12.8/Submit) id i4CJIlF6095429 for linux-mm@kvack.org; Wed, 12 May 2004 12:18:47 -0700 (PDT) (envelope-from thparkth) Date: Wed, 12 May 2004 12:18:47 -0700 (PDT) Message-Id: <200405121918.i4CJIlF6095429@newsguy.com> From: Andrew Crawford Subject: Re: The long, long life of an inactive_dirty page Sender: owner-linux-mm@kvack.org Return-Path: To: linux-mm@kvack.org List-ID: > That information is not achievable in a reliable way, ever. Simply because > it takes a not-even-near-inifintely small amount of time to gather all the > stats, during which the other cpu can change all the underlying data away > under your nose. Although that is of course true, it's also well understood and a factor with any operating system. Nevertheless, it would be useful to have a picture of how much memory is available right now. An inaccurate (within reason) indication *would* be better than none at all. Just to gather opinions, and since we've been having a bit of a heated discussion about it here at work, how would you good people define "available RAM"? and which memory metrics would make it up? My definition would be "RAM which can be allocated and used without the need to write any pages". I.e if the memory needs laundered first but no actual writes need to be done, that's fine and I'll count it as available. So I'd be counting Free + Inactive_Clean + The clean part of inactive_dirty (which can't be measured at present) Is there anything else that should be on there? Cheers, Andrew -- 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: aart@kvack.org