From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751908AbZH2PKX (ORCPT ); Sat, 29 Aug 2009 11:10:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751814AbZH2PKW (ORCPT ); Sat, 29 Aug 2009 11:10:22 -0400 Received: from cam-admin0.cambridge.arm.com ([193.131.176.58]:40629 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751813AbZH2PKW (ORCPT ); Sat, 29 Aug 2009 11:10:22 -0400 Subject: Re: [PATCH 1/2] kmemleak: Inform kmemleak about kernel stack allocation From: Catalin Marinas To: Ingo Molnar Cc: x86@kernel.org, linux-kernel@vger.kernel.org, Ingo Molnar In-Reply-To: <1251556083.5518.2.camel@pc1117.cambridge.arm.com> References: <20090827165927.27901.97270.stgit@pc1117.cambridge.arm.com> <20090827170253.27901.33997.stgit@pc1117.cambridge.arm.com> <20090829132954.GB24123@elte.hu> <1251556083.5518.2.camel@pc1117.cambridge.arm.com> Content-Type: text/plain Organization: ARM Ltd Date: Sat, 29 Aug 2009 16:08:42 +0100 Message-Id: <1251558522.5923.1.camel@pc1117.cambridge.arm.com> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 29 Aug 2009 15:08:42.0986 (UTC) FILETIME=[9906ACA0:01CA28BA] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2009-08-29 at 15:28 +0100, Catalin Marinas wrote: > On Sat, 2009-08-29 at 15:29 +0200, Ingo Molnar wrote: > > * Catalin Marinas wrote: > > > > > Traversing all the tasks in the system for scanning the kernel > > > stacks requires locking which increases the kernel latency > > > considerably. This patch informs kmemleak about newly allocated or > > > freed stacks so that they are treated as any other allocated > > > object. Subsequent patch will remove the explicit stack scanning > > > from mm/kmemleak.c. > > > > > > Signed-off-by: Catalin Marinas > > > Cc: Ingo Molnar > > > --- > > > arch/x86/include/asm/thread_info.h | 7 ++++++- > > > arch/x86/kernel/process.c | 2 ++ > > > kernel/fork.c | 7 ++++++- > > > 3 files changed, 14 insertions(+), 2 deletions(-) > > > > > > diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h > > > index fad7d40..f26432a 100644 > > > --- a/arch/x86/include/asm/thread_info.h > > > +++ b/arch/x86/include/asm/thread_info.h > > > @@ -162,7 +162,12 @@ struct thread_info { > > > #define __HAVE_ARCH_THREAD_INFO_ALLOCATOR > > > > > > #define alloc_thread_info(tsk) \ > > > - ((struct thread_info *)__get_free_pages(THREAD_FLAGS, THREAD_ORDER)) > > > +({ \ > > > + struct thread_info *ti = (struct thread_info *) \ > > > + __get_free_pages(THREAD_FLAGS, THREAD_ORDER); \ > > > + kmemleak_alloc(ti, THREAD_SIZE, 1, THREAD_FLAGS); \ > > > + ti; \ > > > +}) > > > > Sidenote:this used to be a trivial wrapper to gfp so it was > > borderline OK as a CPP macro - now it's a non-trivial CPP wrapper > > macro which is not OK. Mind converting it to an inline function? > > I tried this first but got compilation errors in files that didn't even > call this function. To make it workable, thread_info.h would need to > include additional headers. If that's acceptable, I can post an updated > patch. Actually I think it's only the kmemleak.h header but it would get included via thread_info.h in many other files. An alternative is to make kmemleak_alloc() etc. return the pointer passed as argument and keep the macro something like: kmemleak_alloc(__get_free_pages(...), ...) though it is still a bit long. -- Catalin