From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 6 Sep 2004 13:10:27 -0700 From: Andrew Morton Subject: Re: swapping and the value of /proc/sys/vm/swappiness Message-Id: <20040906131027.227b99ac.akpm@osdl.org> In-Reply-To: <413CB661.6030303@sgi.com> References: <413CB661.6030303@sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Ray Bryant Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, riel@redhat.com, piggin@cyberone.com.au, mbligh@aracnet.com, kernel@kolivas.org List-ID: Ray Bryant wrote: > > A scan of the change logs for swappiness related changes shows nothing that > might explain these changes. My question is: "Is this change in behavior > deliberate, or just a side effect of other changes that were made in the vm?" It'll be accidental side-effects arising from changes to other parts of the page reclaim code. > and "What kind of swappiness behavior might I expect to find in future kernels?". Hopefully very little. Unless we choose to deliberately change the swapout behaviour. The code in there is complex and as you've seen, has surprising interactions. And changes have been made without sufficiently broad testing. So I'll be setting the bar much higher for changes to vmscan.c. It takes a *lot* of work to demonstrate that a change in there does what it's supposed to do without breaking other things. That being said, your tests are interesting. There's a wide spread of results across different kernel versions and across different swappiness settings. But the question is: which behaviour is correct for your users, and why? -- 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