From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268314AbUHFWBM (ORCPT ); Fri, 6 Aug 2004 18:01:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266116AbUHFWBL (ORCPT ); Fri, 6 Aug 2004 18:01:11 -0400 Received: from omx1-ext.sgi.com ([192.48.179.11]:34976 "EHLO omx1.americas.sgi.com") by vger.kernel.org with ESMTP id S268229AbUHFWAJ (ORCPT ); Fri, 6 Aug 2004 18:00:09 -0400 Message-ID: <4113FFF9.3010609@sgi.com> Date: Fri, 06 Aug 2004 17:02:33 -0500 From: Josh Aas User-Agent: Mozilla Thunderbird 0.7.3 (X11/20040803) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Andrew Morton CC: linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org Subject: Re: [PATCH] improve speed of freeing bootmem References: <4113DB63.9020706@sgi.com> <20040806125216.30405230.akpm@osdl.org> In-Reply-To: <20040806125216.30405230.akpm@osdl.org> Content-Type: multipart/mixed; boundary="------------050603030907020403010400" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org This is a multi-part message in MIME format. --------------050603030907020403010400 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit New patch is attached. Signed-off-by: Tony Luck Signed-off-by: Josh Aas -- Josh Aas Silicon Graphics, Inc. (SGI) Linux System Software 651-683-3068 Andrew Morton wrote: > Josh Aas wrote: > >>Attached is a patch that greatly improves the speed of freeing boot >>memory. > > > hm, OK. I have a vague feeling that Bill Irwin had patches to fix this up > ages ago. > > > A few nits: > > >>--- a/mm/bootmem.c 2004-08-05 15:33:39.000000000 -0500 >>+++ b/mm/bootmem.c 2004-08-06 13:42:33.000000000 -0500 >>@@ -259,6 +259,7 @@ static unsigned long __init free_all_boo >> unsigned long i, count, total = 0; >> unsigned long idx; >> unsigned long *map; >>+ int gofast = 0; >> >> BUG_ON(!bdata->node_bootmem_map); >> >>@@ -267,14 +268,32 @@ static unsigned long __init free_all_boo >> page = virt_to_page(phys_to_virt(bdata->node_boot_start)); >> idx = bdata->node_low_pfn - (bdata->node_boot_start >> PAGE_SHIFT); >> map = bdata->node_bootmem_map; >>+ if (bdata->node_boot_start == 0 || >>+ ffs(bdata->node_boot_start) - PAGE_SHIFT > ffs(BITS_PER_LONG)) >>+ gofast = 1; > > > A comment describing the above reasoning would be nice. > > >> for (i = 0; i < idx; ) { >> unsigned long v = ~map[i / BITS_PER_LONG]; >>- if (v) { >>+ if (gofast && v == ~0UL) { >>+ int j; >>+ >>+ count += BITS_PER_LONG; >>+ ClearPageReservedNoAtomic(page); >>+ set_page_count(page, 1); >>+ for (j = 1; j < BITS_PER_LONG; j++) { >>+ if (j + 16 < BITS_PER_LONG) { >>+ prefetchw(page + j + 16); >>+ } > > > The whitespace/tabbing has gone funny here. > > >>+#define ClearPageReservedNoAtomic(page) (page)->flags &= ~(1UL << PG_reserved) > > > The naming convention we used in 2.4 for the nonatomic operation was > __ClearPageReserved(), so can we please stick with that? > > And this macro can use __clear_bit() rather than open-coding it. --------------050603030907020403010400 Content-Type: text/x-patch; name="bootmem5.patch" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="bootmem5.patch" --- mm/bootmem.c.orig 2004-08-05 15:33:39.000000000 -0500 +++ mm/bootmem.c 2004-08-06 16:52:41.000000000 -0500 @@ -259,6 +259,7 @@ static unsigned long __init free_all_boo unsigned long i, count, total = 0; unsigned long idx; unsigned long *map; + int gofast = 0; BUG_ON(!bdata->node_bootmem_map); @@ -267,14 +268,33 @@ static unsigned long __init free_all_boo page = virt_to_page(phys_to_virt(bdata->node_boot_start)); idx = bdata->node_low_pfn - (bdata->node_boot_start >> PAGE_SHIFT); map = bdata->node_bootmem_map; + /* Check physaddr is O(LOG2(BITS_PER_LONG)) page aligned */ + if (bdata->node_boot_start == 0 || + ffs(bdata->node_boot_start) - PAGE_SHIFT > ffs(BITS_PER_LONG)) + gofast = 1; for (i = 0; i < idx; ) { unsigned long v = ~map[i / BITS_PER_LONG]; - if (v) { + if (gofast && v == ~0UL) { + int j; + + count += BITS_PER_LONG; + __ClearPageReserved(page); + set_page_count(page, 1); + for (j = 1; j < BITS_PER_LONG; j++) { + if (j + 16 < BITS_PER_LONG) { + prefetchw(page + j + 16); + } + __ClearPageReserved(page + j); + } + __free_pages(page, ffs(BITS_PER_LONG)-1); + i += BITS_PER_LONG; + page += BITS_PER_LONG; + } else if (v) { unsigned long m; for (m = 1; m && i < idx; m<<=1, page++, i++) { if (v & m) { count++; - ClearPageReserved(page); + __ClearPageReserved(page); set_page_count(page, 1); __free_page(page); } @@ -294,7 +314,7 @@ static unsigned long __init free_all_boo count = 0; for (i = 0; i < ((bdata->node_low_pfn-(bdata->node_boot_start >> PAGE_SHIFT))/8 + PAGE_SIZE-1)/PAGE_SIZE; i++,page++) { count++; - ClearPageReserved(page); + __ClearPageReserved(page); set_page_count(page, 1); __free_page(page); } --- include/linux/page-flags.h.orig 2004-08-06 13:43:36.000000000 -0500 +++ include/linux/page-flags.h 2004-08-06 15:16:29.000000000 -0500 @@ -236,6 +236,7 @@ extern unsigned long __read_page_state(u #define PageReserved(page) test_bit(PG_reserved, &(page)->flags) #define SetPageReserved(page) set_bit(PG_reserved, &(page)->flags) #define ClearPageReserved(page) clear_bit(PG_reserved, &(page)->flags) +#define __ClearPageReserved(page) __clear_bit(PG_reserved, &(page)->flags) #define SetPagePrivate(page) set_bit(PG_private, &(page)->flags) #define ClearPagePrivate(page) clear_bit(PG_private, &(page)->flags) --------------050603030907020403010400--