From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx167.postini.com [74.125.245.167]) by kanga.kvack.org (Postfix) with SMTP id 0B2746B0062 for ; Mon, 10 Sep 2012 13:41:09 -0400 (EDT) Received: by iagk10 with SMTP id k10so2603525iag.14 for ; Mon, 10 Sep 2012 10:41:09 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <5038E7AA.5030107@gmail.com> <1347209830.7709.39.camel@deadeye.wl.decadent.org.uk> <504CCECF.9020104@redhat.com> From: Shentino Date: Mon, 10 Sep 2012 10:40:28 -0700 Message-ID: Subject: Re: Consider for longterm kernels: mm: avoid swapping out with swappiness==0 Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Cong Wang Cc: linux-mm@kvack.org, stable@vger.kernel.org On Mon, Sep 10, 2012 at 10:07 AM, Shentino wrote: > On Mon, Sep 10, 2012 at 6:36 AM, Cong Wang wrote: >> On Sun, 09 Sep 2012 at 18:03 GMT, Shentino wrote: >>> >>> Just curious, but what theoretically would happen if someone were to >>> want to set swappiness to 200 or something? >>> >>> Should it be sorta like vfs_cache_pressure? >>> >> >> >> How could it be set to 200? As 0~100 is valid: >> >> { >> .procname = "swappiness", >> .data = &vm_swappiness, >> .maxlen = sizeof(vm_swappiness), >> .mode = 0644, >> .proc_handler = proc_dointvec_minmax, >> .extra1 = &zero, >> .extra2 = &one_hundred, >> }, > > My comment/question was more abstract and focusing on the comparison > to vfs_cache_pressure. Just to be clear about what I meant. Both swapping and reclaiming from dentry/inode caches both share the common factor of being alternatives to reclaiming from page cache when memory is tight. So I was wondering how similiar in effect these two knobs should be. One possible use case off the top of my head is a file server that banks heavily on page cache and spends most of its runtime sending file data over the network. It might be overkill but swappiness > 100 might actually be beneficial here. I have no numbers to back it up though as it's a rough idea. Sorry if I'm butting in on the subject but I was curious about the idea. Also still learning how to pos tin general on the kernel lists, so apologies if I've been rude or anything. > > :P >> >> -- >> 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 -- 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