From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from atlas.CARNet.hr (root@atlas.CARNet.hr [161.53.123.163]) by kvack.org (8.8.7/8.8.7) with ESMTP id SAA15165 for ; Thu, 12 Nov 1998 18:12:34 -0500 Subject: Re: unexpected paging during large file reads in 2.1.127 References: Reply-To: Zlatko.Calusic@CARNet.hr From: Zlatko Calusic Date: 12 Nov 1998 23:45:42 +0100 In-Reply-To: Rik van Riel's message of "Thu, 12 Nov 1998 14:39:53 +0100 (CET)" Message-ID: <87k910bkdl.fsf@atlas.CARNet.hr> Sender: owner-linux-mm@kvack.org To: Rik van Riel Cc: "David J. Fred" , linux-kernel@vger.rutgers.edu, Linux-MM List List-ID: Rik van Riel writes: > On 12 Nov 1998, Zlatko Calusic wrote: > > "David J. Fred" writes: > > > > > Summary: When doing large file reads from disk the system pages > > > unexpectedly causing moderate to severe degradation in I/O > > > and overall system performance even though there is plenty of > > > memory. > > > > Page cache is definitely too aggressive on recent kernels. I > > developed a small patch that avoids excessive swapouts. It helps > > kswapd to have less trouble reusing pages from page cache. > > Agreed, we should do something about that. > > > + age_page(page); > > + age_page(page); > > age_page(page); > > Do I hear "priority paging"? :)) > > > count_max = (limit<<2) >> (priority>>1); > > count_min = (limit<<2) >> (priority); > > Maybe increasing these has the same effect but with > the advantage of keeping page aging intact. > Maybe, but then again maybe not. I have a feeling that change like that could easily make kswapd a CPU pig. We are aging pages, so that they don't get reaped easily, and then trying to compensate that with heavier scanning. Doesn't sound like a good idea. Sizif's job. But still, looks interesting, so I'm just going to compile one test kernel with bigger count limits, for the fun's sake... :) [Cc: Linux-MM] Regards, -- Posted by Zlatko Calusic E-mail: --------------------------------------------------------------------- A chicken is an egg's way of producing more eggs. -- This is a majordomo managed list. To unsubscribe, send a message with the body 'unsubscribe linux-mm me@address' to: majordomo@kvack.org