From mboxrd@z Thu Jan 1 00:00:00 1970 From: Con Kolivas Subject: Re: [PATCH] mm: swap prefetch improvements Date: Tue, 22 May 2007 20:37:54 +1000 References: <20070430162007.ad46e153.akpm@linux-foundation.org> <200705222020.58474.kernel@kolivas.org> <20070522102530.GB2344@elte.hu> In-Reply-To: <20070522102530.GB2344@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200705222037.54741.kernel@kolivas.org> Sender: owner-linux-mm@kvack.org Return-Path: To: Ingo Molnar Cc: Antonino Ingargiola , Nick Piggin , Ray Lee , ck list , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: On Tuesday 22 May 2007 20:25, Ingo Molnar wrote: > * Con Kolivas wrote: > > > > there was nothing else running on the system - so i suspect the > > > > swapin activity flagged 'itself' as some 'other' activity and > > > > stopped? The swapins happened in 4 bursts, separated by 5 seconds > > > > total idleness. > > > > > > I've noted burst swapins separated by some seconds of pause in my > > > desktop system too (with sp_tester and an idle gnome). > > > > That really is expected, as just about anything, including journal > > writeout, would be enough to put it back to sleep for 5 more seconds. > > note that nothing like that happened on my system - in the > swap-prefetch-off case there was _zero_ IO activity during the sleep > period. Ok, granted it's _very_ conservative. I really don't want to risk its presence being a burden on anything, and the iowait it induces probably makes it turn itself off for another PREFETCH_DELAY (5s). I really don't want to cross the line to where it is detrimental in any way. Not dropping out on a cond_resched and perhaps making the delay tunable should be enough to make it a little less "sleepy". -- -ck -- 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: email@kvack.org