From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 22 Mar 2001 14:58:10 +0000 From: "Stephen C. Tweedie" Subject: Thinko in kswapd? Message-ID: <20010322145810.A7296@redhat.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="Kj7319i9nmIyA2yE" Content-Disposition: inline Sender: owner-linux-mm@kvack.org Return-Path: To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Alan Cox , Stephen Tweedie , arjanv@redhat.com, Linus Torvalds List-ID: --Kj7319i9nmIyA2yE Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Hi, There is what appears to be a simple thinko in kswapd. We really ought to keep kswapd running as long as there is either a free space or an inactive page shortfall; but right now we only keep going if _both_ are short. Diff below. With this change, I've got a 64MB box running Applix and Star Office with multiple open documents plus a few other big apps running, and switching desktops or going between documents is once more nice and snappy. Running a normal heavily populated desktop in 256MB used to be painful, with much apparently unnecessary swapping, if we had background page-cache intensive operations (eg find|wc) going on: the patched kernel feels much better interactively, presumably because kswapd is now doing the work it is supposed to do, instead of forcing normal apps to go into page stealing mode themselves. --Stephen --Kj7319i9nmIyA2yE Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename="2.4.2-ac20.kswap.diff" --- mm/vmscan.c.~1~ Fri Mar 16 15:39:24 2001 +++ mm/vmscan.c Thu Mar 22 13:05:37 2001 @@ -1010,7 +1010,7 @@ * We go to sleep for one second, but if it's needed * we'll be woken up earlier... */ - if (!free_shortage() || !inactive_shortage()) { + if (!free_shortage() && !inactive_shortage()) { interruptible_sleep_on_timeout(&kswapd_wait, HZ); /* * If we couldn't free enough memory, we see if it was --Kj7319i9nmIyA2yE-- -- 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.eu.org/Linux-MM/