Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268733AbUIQNT7 (ORCPT ); Fri, 17 Sep 2004 09:19:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S268730AbUIQNT7 (ORCPT ); Fri, 17 Sep 2004 09:19:59 -0400 Received: from dmz.tecosim.com ([195.135.152.162]:5043 "EHLO dmz.tecosim.de") by vger.kernel.org with ESMTP id S268734AbUIQNSh (ORCPT ); Fri, 17 Sep 2004 09:18:37 -0400 Date: Fri, 17 Sep 2004 15:18:30 +0200 From: Utz Lehmann To: Ulrich Drepper Cc: Utz Lehmann , Arjan van de Ven , linux-kernel@vger.kernel.org Subject: Re: [PATCH] flexmmap: optimise mmap_base gap for hard limited stack Message-ID: <20040917131829.GA15000@de.tecosim.com> References: <20040916165613.GA10825@de.tecosim.com> <20040916174529.GA16439@devserv.devel.redhat.com> <20040916182139.GA21870@de.tecosim.com> <4149E46E.7010804@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4149E46E.7010804@redhat.com> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4600 Lines: 126 Ulrich Drepper [drepper@redhat.com] wrote: > > A check for CAP_SYS_RESOURCE can be added. But i dont think it's worth. > > It is needed. Otherwise how do you allow increasing the stack size > again once it has been limited? I've no problem with using the smallest > reserved stack region with !CAP_SYS_RESOURCE, but otherwise the existing > method should be used. I made that change. The following patch only reduce the gap when the application can not extend the stack space anyway (hard limited stack && !CAP_SYS_RESOURCE). All other cases stay unchanged except for the 1 MB hole for soft limited stacks >128 MB. It gave a nice way for making most of the default 128 MB gap usable for applications. Just run them with a hard stack limit. Now i can allocate more than 3.8GiB in one chunk on x86 (this patch + exec-shield + 4g/4g + ulimit -H -s 8192). Signed-off-by: Utz Lehmann diff -Nrup linux-2.6.9-rc2/arch/i386/mm/mmap.c linux-2.6.9-rc2-gap4/arch/i386/mm/mmap.c --- linux-2.6.9-rc2/arch/i386/mm/mmap.c 2004-09-16 11:18:15.363366420 +0200 +++ linux-2.6.9-rc2-gap4/arch/i386/mm/mmap.c 2004-09-17 12:14:16.734968291 +0200 @@ -30,10 +30,13 @@ /* * Top of mmap area (just below the process stack). * - * Leave an at least ~128 MB hole. + * Leave an at least 1 MB hole between stack and mmap_base. + * Leave an at least 128 MB gap between TASK_SIZE and mmap_base with a + * soft rlimit stack. */ -#define MIN_GAP (128*1024*1024) -#define MAX_GAP (TASK_SIZE/6*5) +#define MIN_HOLE (1*1024*1024) +#define MIN_GAP (128*1024*1024 - MIN_HOLE) +#define MAX_GAP (TASK_SIZE/6*5 - MIN_HOLE) static inline unsigned long mmap_base(struct mm_struct *mm) { @@ -43,8 +46,11 @@ static inline unsigned long mmap_base(st gap = MIN_GAP; else if (gap > MAX_GAP) gap = MAX_GAP; + if ((gap > current->rlim[RLIMIT_STACK].rlim_max) && + !capable(CAP_SYS_RESOURCE)) + gap = current->rlim[RLIMIT_STACK].rlim_max; - return TASK_SIZE - (gap & PAGE_MASK); + return TASK_SIZE - ((gap + MIN_HOLE) & PAGE_MASK); } /* diff -Nrup linux-2.6.9-rc2/arch/ppc64/mm/mmap.c linux-2.6.9-rc2-gap4/arch/ppc64/mm/mmap.c --- linux-2.6.9-rc2/arch/ppc64/mm/mmap.c 2004-09-16 11:18:19.760799910 +0200 +++ linux-2.6.9-rc2-gap4/arch/ppc64/mm/mmap.c 2004-09-17 12:15:05.572696938 +0200 @@ -30,10 +30,13 @@ /* * Top of mmap area (just below the process stack). * - * Leave an at least ~128 MB hole. + * Leave an at least 1 MB hole between stack and mmap_base. + * Leave an at least 128 MB gap between TASK_SIZE and mmap_base with a + * soft rlimit stack. */ -#define MIN_GAP (128*1024*1024) -#define MAX_GAP (TASK_SIZE/6*5) +#define MIN_HOLE (1*1024*1024) +#define MIN_GAP (128*1024*1024 - MIN_HOLE) +#define MAX_GAP (TASK_SIZE/6*5 - MIN_HOLE) static inline unsigned long mmap_base(void) { @@ -43,8 +46,11 @@ static inline unsigned long mmap_base(vo gap = MIN_GAP; else if (gap > MAX_GAP) gap = MAX_GAP; + if ((gap > current->rlim[RLIMIT_STACK].rlim_max) && + !capable(CAP_SYS_RESOURCE)) + gap = current->rlim[RLIMIT_STACK].rlim_max; - return TASK_SIZE - (gap & PAGE_MASK); + return TASK_SIZE - ((gap + MIN_HOLE) & PAGE_MASK); } static inline int mmap_is_legacy(void) diff -Nrup linux-2.6.9-rc2/arch/s390/mm/mmap.c linux-2.6.9-rc2-gap4/arch/s390/mm/mmap.c --- linux-2.6.9-rc2/arch/s390/mm/mmap.c 2004-09-16 11:18:19.855787673 +0200 +++ linux-2.6.9-rc2-gap4/arch/s390/mm/mmap.c 2004-09-17 12:15:23.054452086 +0200 @@ -30,10 +30,13 @@ /* * Top of mmap area (just below the process stack). * - * Leave an at least ~128 MB hole. + * Leave an at least 1 MB hole between stack and mmap_base. + * Leave an at least 128 MB gap between TASK_SIZE and mmap_base with a + * soft rlimit stack. */ -#define MIN_GAP (128*1024*1024) -#define MAX_GAP (TASK_SIZE/6*5) +#define MIN_HOLE (1*1024*1024) +#define MIN_GAP (128*1024*1024 - MIN_HOLE) +#define MAX_GAP (TASK_SIZE/6*5 - MIN_HOLE) static inline unsigned long mmap_base(void) { @@ -43,8 +46,11 @@ static inline unsigned long mmap_base(vo gap = MIN_GAP; else if (gap > MAX_GAP) gap = MAX_GAP; + if ((gap > current->rlim[RLIMIT_STACK].rlim_max) && + !capable(CAP_SYS_RESOURCE)) + gap = current->rlim[RLIMIT_STACK].rlim_max; - return TASK_SIZE - (gap & PAGE_MASK); + return TASK_SIZE - ((gap + MIN_HOLE) & PAGE_MASK); } static inline int mmap_is_legacy(void) - 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/