Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S269266AbUINLcp (ORCPT ); Tue, 14 Sep 2004 07:32:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S269286AbUINL3R (ORCPT ); Tue, 14 Sep 2004 07:29:17 -0400 Received: from mx2.elte.hu ([157.181.151.9]:22252 "EHLO mx2.elte.hu") by vger.kernel.org with ESMTP id S269297AbUINLTI (ORCPT ); Tue, 14 Sep 2004 07:19:08 -0400 Date: Tue, 14 Sep 2004 12:50:48 +0200 From: Ingo Molnar To: Andrew Morton Cc: linux-kernel@vger.kernel.org Subject: [patch] sched, mm: fix scheduling latencies in copy_page_range() Message-ID: <20040914105048.GA31238@elte.hu> References: <20040914091529.GA21553@elte.hu> <20040914093855.GA23258@elte.hu> <20040914095110.GA24094@elte.hu> <20040914095731.GA24622@elte.hu> <20040914100652.GB24622@elte.hu> <20040914101904.GD24622@elte.hu> <20040914102517.GE24622@elte.hu> <20040914104449.GA30790@elte.hu> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="SLDf9lqlvOQaIe6s" Content-Disposition: inline In-Reply-To: <20040914104449.GA30790@elte.hu> User-Agent: Mutt/1.4.1i X-ELTE-SpamVersion: MailScanner 4.31.6-itk1 (ELTE 1.2) SpamAssassin 2.63 ClamAV 0.73 X-ELTE-VirusStatus: clean X-ELTE-SpamCheck: no X-ELTE-SpamCheck-Details: score=-4.9, required 5.9, autolearn=not spam, BAYES_00 -4.90 X-ELTE-SpamLevel: X-ELTE-SpamScore: -4 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1735 Lines: 59 --SLDf9lqlvOQaIe6s Content-Type: text/plain; charset=us-ascii Content-Disposition: inline The attached patch does a lock-break in copy_page_range() if needed, to reduce scheduling latencies. has been tested as part of the -VP patchset. Ingo --SLDf9lqlvOQaIe6s Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename="fix-latency-copy_page_range.patch" The attached patch does a lock-break in copy_page_range() if needed, to reduce scheduling latencies. has been tested as part of the -VP patchset. Signed-off-by: Ingo Molnar --- linux/mm/memory.c.orig +++ linux/mm/memory.c @@ -337,6 +337,25 @@ cont_copy_pte_range_noset: } src_pte++; dst_pte++; + /* + * We are holding two locks at this point - + * any of them could generate latencies in + * another task on another CPU: + */ + if (need_resched() || + need_lockbreak(&src->page_table_lock) || + need_lockbreak(&dst->page_table_lock)) + { + pte_unmap_nested(src_pte); + pte_unmap(dst_pte); + spin_unlock(&src->page_table_lock); + spin_unlock(&dst->page_table_lock); + cond_resched(); + spin_lock(&dst->page_table_lock); + spin_lock(&src->page_table_lock); + dst_pte = pte_offset_map(dst_pmd, address); + src_pte = pte_offset_map_nested(src_pmd, address); + } } while ((unsigned long)src_pte & PTE_TABLE_MASK); pte_unmap_nested(src_pte-1); pte_unmap(dst_pte-1); --SLDf9lqlvOQaIe6s-- - 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/