Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932116AbVJVBsL (ORCPT ); Fri, 21 Oct 2005 21:48:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932117AbVJVBsL (ORCPT ); Fri, 21 Oct 2005 21:48:11 -0400 Received: from mail27.syd.optusnet.com.au ([211.29.133.168]:49826 "EHLO mail27.syd.optusnet.com.au") by vger.kernel.org with ESMTP id S932116AbVJVBsJ (ORCPT ); Fri, 21 Oct 2005 21:48:09 -0400 From: Con Kolivas To: linux kernel mailing list Subject: Re: [PATCH] mm - swap prefetch magnify Date: Sat, 22 Oct 2005 11:47:58 +1000 User-Agent: KMail/1.8.3 Cc: Andrew Morton , ck list References: <200510221120.44473.kernel@kolivas.org> In-Reply-To: <200510221120.44473.kernel@kolivas.org> MIME-Version: 1.0 Content-Type: Multipart/Mixed; boundary="Boundary-00=_PpZWDYahsN/c6hv" Message-Id: <200510221147.59059.kernel@kolivas.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2629 Lines: 89 --Boundary-00=_PpZWDYahsN/c6hv Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline On Sat, 22 Oct 2005 11:20, Con Kolivas wrote: > Testing has confirmed much larger prefetch values work well. Bah.. Sorry take this one instead. Just make sure that no matter how little ram we have prefetch is enabled. Con --- --Boundary-00=_PpZWDYahsN/c6hv Content-Type: text/x-diff; charset="iso-8859-1"; name="mm-swap_prefetch_magnify-1.patch" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="mm-swap_prefetch_magnify-1.patch" The current number of pages prefetched by swap_prefetch is very gentle, and we are very cautious about whether prefetching is appropriate or not so we can increase the size substantially. Make the prefetch size magnitudes larger, being proportional to memory size instead of the square root of it. Fix the last_free calculation to work better with larger prefetch sizes. Signed-off-by: Con Kolivas Index: linux-2.6.14-rc5-ck1/mm/swap_prefetch.c =================================================================== --- linux-2.6.14-rc5-ck1.orig/mm/swap_prefetch.c 2005-10-22 10:14:26.000000000 +1000 +++ linux-2.6.14-rc5-ck1/mm/swap_prefetch.c 2005-10-22 10:36:30.000000000 +1000 @@ -24,7 +24,7 @@ #define PREFETCH_INTERVAL (HZ) /* sysctl - how many SWAP_CLUSTER_MAX pages to prefetch at a time */ -int swap_prefetch = 1; +int swap_prefetch; struct swapped_root { unsigned long busy; /* vm busy */ @@ -71,9 +71,7 @@ void __init prepare_prefetch(void) mapped_limit = mem / 3 * 2; /* Set initial swap_prefetch value according to memory size */ - mem /= SWAP_CLUSTER_MAX * 1000; - while ((mem >>= 1)) - swap_prefetch++; + swap_prefetch = mem / 10000 ? : 1; } /* @@ -307,10 +305,9 @@ static int prefetch_suitable(void) * (eg during file reads) */ if (last_free) { - if (temp_free + SWAP_CLUSTER_MAX + prefetch_pages() < - last_free) { - last_free = temp_free; - goto out; + if (temp_free + SWAP_CLUSTER_MAX < last_free) { + last_free = temp_free; + goto out; } } else last_free = temp_free; @@ -375,6 +372,7 @@ static enum trickle_return trickle_swap( case TRICKLE_FAILED: break; case TRICKLE_SUCCESS: + last_free--; pages++; break; case TRICKLE_DELAY: --Boundary-00=_PpZWDYahsN/c6hv-- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/