From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935821Ab3DHTjO (ORCPT ); Mon, 8 Apr 2013 15:39:14 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:49261 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935727Ab3DHTjN (ORCPT ); Mon, 8 Apr 2013 15:39:13 -0400 Date: Mon, 8 Apr 2013 12:39:11 -0700 From: Andrew Morton To: Andrew Shewmaker Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, alan@lxorguk.ukuu.org.uk, simon.jeons@gmail.com, ric.masonn@gmail.com Subject: Re: [PATCH v8 2/3] mm: replace hardcoded 3% with admin_reserve_pages knob Message-Id: <20130408123911.6f1101fd988bcc680eb37c46@linux-foundation.org> In-Reply-To: <20130408190510.GB2321@localhost.localdomain> References: <20130408190510.GB2321@localhost.localdomain> X-Mailer: Sylpheed 3.2.0beta5 (GTK+ 2.24.10; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 8 Apr 2013 15:05:10 -0400 Andrew Shewmaker wrote: > Add an admin_reserve_kbytes knob to allow admins to change the > hardcoded memory reserve to something other than 3%, which > may be multiple gigabytes on large memory systems. Only about > 8MB is necessary to enable recovery in the default mode, and > only a few hundred MB are required even when overcommit is > disabled. And the only change that v8 made was to revert earlier fixes, so I'll skip this version as well. --- a/include/linux/mm.h~mm-replace-hardcoded-3%-with-admin_reserve_pages-knob-v8 +++ a/include/linux/mm.h @@ -45,7 +45,6 @@ extern int sysctl_legacy_va_layout; #include extern unsigned long sysctl_user_reserve_kbytes; -extern unsigned long sysctl_admin_reserve_kbytes; #define nth_page(page,n) pfn_to_page(page_to_pfn((page)) + (n)) --- a/kernel/sysctl.c~mm-replace-hardcoded-3%-with-admin_reserve_pages-knob-v8 +++ a/kernel/sysctl.c @@ -97,6 +97,7 @@ /* External variables not in a header file. */ extern int sysctl_overcommit_memory; extern int sysctl_overcommit_ratio; +extern unsigned long sysctl_admin_reserve_kbytes; extern int max_threads; extern int suid_dumpable; #ifdef CONFIG_COREDUMP --- a/mm/mmap.c~mm-replace-hardcoded-3%-with-admin_reserve_pages-knob-v8 +++ a/mm/mmap.c @@ -168,7 +168,7 @@ int __vm_enough_memory(struct mm_struct * Reserve some for root */ if (!cap_sys_admin) - free -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10); + free -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10); if (free > pages) return 0; --- a/mm/nommu.c~mm-replace-hardcoded-3%-with-admin_reserve_pages-knob-v8 +++ a/mm/nommu.c @@ -1932,7 +1932,7 @@ int __vm_enough_memory(struct mm_struct * Reserve some for root */ if (!cap_sys_admin) - free -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10); + free -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10); if (free > pages) return 0; _