From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 8 Mar 2001 20:17:14 +0000 From: "Stephen C. Tweedie" Subject: Re: nr_async_pages and swapin readahead on -ac series Message-ID: <20010308201714.O10437@redhat.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: ; from marcelo@conectiva.com.br on Wed, Mar 07, 2001 at 10:57:21PM -0300 Sender: owner-linux-mm@kvack.org Return-Path: To: Marcelo Tosatti Cc: Rik van Riel , linux-mm@kvack.org, Alan Cox List-ID: Hi, On Wed, Mar 07, 2001 at 10:57:21PM -0300, Marcelo Tosatti wrote: > > On the latest 2.4 -ac series, nr_async_pages is only being used to count > swap outs, and not for both swap reads and writes (as Linus tree does). Seems fine to me. > The problem is that nr_async_pages is used to limit swapin readahead based > on the number of on flight swap pages (mm/memory.c::swapin_readahead): That's probably a mistake: we don't throttle readahead on normal files in this manner. Swapin is always synchronous: it happens in response to a task's page fault. As such it is always going to be rate-limited automatically. I don't think it's too important to count reads in nr_async_pages, nor to throttle readaheads if nr_async_pages is too large. Cheers, Stephen -- 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/