From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757245AbZHNWr5 (ORCPT ); Fri, 14 Aug 2009 18:47:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756880AbZHNWr4 (ORCPT ); Fri, 14 Aug 2009 18:47:56 -0400 Received: from cam-admin0.cambridge.arm.com ([193.131.176.58]:50774 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752751AbZHNWrz (ORCPT ); Fri, 14 Aug 2009 18:47:55 -0400 Subject: [PATCH] kmemleak: Allow rescheduling during an object scanning From: Catalin Marinas To: Ingo Molnar Cc: Linus Torvalds , Andrew Morton , linux-kernel@vger.kernel.org In-Reply-To: <1250289913.5085.17.camel@pc1117.cambridge.arm.com> References: <20090812205215.GA21451@elte.hu> <1250289913.5085.17.camel@pc1117.cambridge.arm.com> Content-Type: text/plain Organization: ARM Ltd Date: Fri, 14 Aug 2009 23:47:44 +0100 Message-Id: <1250290064.5085.20.camel@pc1117.cambridge.arm.com> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 14 Aug 2009 22:47:44.0856 (UTC) FILETIME=[3D104580:01CA1D31] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If the object size is bigger than a predefined value (4K in this case), release the object lock during scanning and call cond_resched(). Re-acquire the lock after rescheduling and test whether the object is still valid. Signed-off-by: Catalin Marinas --- mm/kmemleak.c | 21 +++++++++++++++++---- 1 files changed, 17 insertions(+), 4 deletions(-) diff --git a/mm/kmemleak.c b/mm/kmemleak.c index 4872673..6debe0d 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -107,6 +107,7 @@ #define SECS_FIRST_SCAN 60 /* delay before the first scan */ #define SECS_SCAN_WAIT 600 /* subsequent auto scanning delay */ #define GRAY_LIST_PASSES 25 /* maximum number of gray list scans */ +#define MAX_SCAN_SIZE 4096 /* maximum size of a scanned block */ #define BYTES_PER_POINTER sizeof(void *) @@ -642,6 +643,7 @@ static void make_black_object(unsigned long ptr) spin_lock_irqsave(&object->lock, flags); object->min_count = -1; + object->flags |= OBJECT_NO_SCAN; spin_unlock_irqrestore(&object->lock, flags); put_object(object); } @@ -949,10 +951,21 @@ static void scan_object(struct kmemleak_object *object) if (!(object->flags & OBJECT_ALLOCATED)) /* already freed object */ goto out; - if (hlist_empty(&object->area_list)) - scan_block((void *)object->pointer, - (void *)(object->pointer + object->size), object, 0); - else + if (hlist_empty(&object->area_list)) { + void *start = (void *)object->pointer; + void *end = (void *)(object->pointer + object->size); + + while (start < end && (object->flags & OBJECT_ALLOCATED) && + !(object->flags & OBJECT_NO_SCAN)) { + scan_block(start, min(start + MAX_SCAN_SIZE, end), + object, 0); + start += MAX_SCAN_SIZE; + + spin_unlock_irqrestore(&object->lock, flags); + cond_resched(); + spin_lock_irqsave(&object->lock, flags); + } + } else hlist_for_each_entry(area, elem, &object->area_list, node) scan_block((void *)(object->pointer + area->offset), (void *)(object->pointer + area->offset