From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from max.phys.uu.nl (max.phys.uu.nl [131.211.32.73]) by kvack.org (8.8.7/8.8.7) with ESMTP id FAA15903 for ; Wed, 18 Nov 1998 05:25:48 -0500 Date: Wed, 18 Nov 1998 09:58:58 +0100 (CET) From: Rik van Riel Reply-To: Rik van Riel Subject: Re: useless report -- perhaps memory allocation problems in 2.1.12[678] In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: Linus Torvalds Cc: "Stephen C. Tweedie" , Jeffrey Hundstad , Linux MM List-ID: On Tue, 17 Nov 1998, Linus Torvalds wrote: > On Tue, 17 Nov 1998, Linus Torvalds wrote: > > > > But whether kswapd should go page-synchronous at some point? Maybe. I can > > see arguments both for and against (the "for" argument is that we prefer > > to have more intense bouts of IO followed by a nice clean wait, while the > > "against" argument is that maybe we want to spread out the thing). > > Oh, well, I'm currently leaning for "for", which means your patch to > page_io.c is what I have now.. I don't like "trickling" pages by > running out of requests or something like that, so having the > occasional nice wait is probably best. It seems like you decided for my point of view before I woke up again, so I'll just let you know that this is one of the reasons why I submitted the original (2.1.90?) patch to you. The other reason was that async, clustered swapouts have a much higher bandwidth than synchronous swapouts. This means we can do more swap I/O without getting into trouble. The only request I have to make is that you use the sysctl tuneable limit pager_daemon.swap_cluster as the limit. Doing this will enable people to optimize their kswapd configuration for multiple swap partitions or disks with loads of tagged queues (or a shortage thereoff). I have found that setting that limit to SWAP_CLUSTER_MAX * number_of_highest_priority_swap_areas doubled swapout performance, leaving 50% extra I/O bandwidth for swapins. cheers, Rik -- slowly getting used to dvorak kbd layout... +-------------------------------------------------------------------+ | Linux memory management tour guide. H.H.vanRiel@phys.uu.nl | | Scouting Vries cubscout leader. http://www.phys.uu.nl/~riel/ | +-------------------------------------------------------------------+ -- This is a majordomo managed list. To unsubscribe, send a message with the body 'unsubscribe linux-mm me@address' to: majordomo@kvack.org