Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760076AbaGOXOX (ORCPT ); Tue, 15 Jul 2014 19:14:23 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:45209 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760035AbaGOXNq (ORCPT ); Tue, 15 Jul 2014 19:13:46 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Helge Deller , James Hogan , "James E.J. Bottomley" , linux-parisc@vger.kernel.org, linux-metag@vger.kernel.org, John David Anglin Subject: [PATCH 3.14 08/66] parisc,metag: Do not hardcode maximum userspace stack size Date: Tue, 15 Jul 2014 16:17:02 -0700 Message-Id: <20140715231702.440835453@linuxfoundation.org> X-Mailer: git-send-email 2.0.0.254.g50f84e3 In-Reply-To: <20140715231702.156040999@linuxfoundation.org> References: <20140715231702.156040999@linuxfoundation.org> User-Agent: quilt/0.63-1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Helge Deller commit 042d27acb64924a0e8a43e972485913a32407beb upstream. This patch affects only architectures where the stack grows upwards (currently parisc and metag only). On those do not hardcode the maximum initial stack size to 1GB for 32-bit processes, but make it configurable via a config option. The main problem with the hardcoded stack size is, that we have two memory regions which grow upwards: stack and heap. To keep most of the memory available for heap in a flexmap memory layout, it makes no sense to hard allocate up to 1GB of the memory for stack which can't be used as heap then. This patch makes the stack size for 32-bit processes configurable and uses 80MB as default value which has been in use during the last few years on parisc and which hasn't showed any problems yet. Signed-off-by: Helge Deller Signed-off-by: James Hogan Cc: "James E.J. Bottomley" Cc: linux-parisc@vger.kernel.org Cc: linux-metag@vger.kernel.org Cc: John David Anglin Signed-off-by: Greg Kroah-Hartman --- arch/metag/include/asm/processor.h | 2 +- arch/parisc/include/asm/processor.h | 5 ++++- arch/parisc/kernel/sys_parisc.c | 6 +++--- mm/Kconfig | 15 +++++++++++++++ 4 files changed, 23 insertions(+), 5 deletions(-) --- a/arch/metag/include/asm/processor.h +++ b/arch/metag/include/asm/processor.h @@ -23,7 +23,7 @@ #define STACK_TOP (TASK_SIZE - PAGE_SIZE) #define STACK_TOP_MAX STACK_TOP /* Maximum virtual space for stack */ -#define STACK_SIZE_MAX (1 << 28) /* 256 MB */ +#define STACK_SIZE_MAX (CONFIG_MAX_STACK_SIZE_MB*1024*1024) /* This decides where the kernel will search for a free chunk of vm * space during mmap's. --- a/arch/parisc/include/asm/processor.h +++ b/arch/parisc/include/asm/processor.h @@ -55,7 +55,10 @@ #define STACK_TOP TASK_SIZE #define STACK_TOP_MAX DEFAULT_TASK_SIZE -#define STACK_SIZE_MAX (1 << 30) /* 1 GB */ +/* Allow bigger stacks for 64-bit processes */ +#define STACK_SIZE_MAX (USER_WIDE_MODE \ + ? (1 << 30) /* 1 GB */ \ + : (CONFIG_MAX_STACK_SIZE_MB*1024*1024)) #endif --- a/arch/parisc/kernel/sys_parisc.c +++ b/arch/parisc/kernel/sys_parisc.c @@ -72,10 +72,10 @@ static unsigned long mmap_upper_limit(vo { unsigned long stack_base; - /* Limit stack size to 1GB - see setup_arg_pages() in fs/exec.c */ + /* Limit stack size - see setup_arg_pages() in fs/exec.c */ stack_base = rlimit_max(RLIMIT_STACK); - if (stack_base > (1 << 30)) - stack_base = 1 << 30; + if (stack_base > STACK_SIZE_MAX) + stack_base = STACK_SIZE_MAX; return PAGE_ALIGN(STACK_TOP - stack_base); } --- a/mm/Kconfig +++ b/mm/Kconfig @@ -580,3 +580,18 @@ config PGTABLE_MAPPING You can check speed with zsmalloc benchmark: https://github.com/spartacus06/zsmapbench + +config MAX_STACK_SIZE_MB + int "Maximum user stack size for 32-bit processes (MB)" + default 80 + range 8 256 if METAG + range 8 2048 + depends on STACK_GROWSUP && (!64BIT || COMPAT) + help + This is the maximum stack size in Megabytes in the VM layout of 32-bit + user processes when the stack grows upwards (currently only on parisc + and metag arch). The stack will be located at the highest memory + address minus the given value, unless the RLIMIT_STACK hard limit is + changed to a smaller value in which case that is used. + + A sane initial value is 80 MB. -- 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/