From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752071Ab3CAXcN (ORCPT ); Fri, 1 Mar 2013 18:32:13 -0500 Received: from mail-pa0-f49.google.com ([209.85.220.49]:49316 "EHLO mail-pa0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751245Ab3CAXcM (ORCPT ); Fri, 1 Mar 2013 18:32:12 -0500 Date: Fri, 1 Mar 2013 18:32:08 -0500 From: Andrew Shewmaker To: akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, alan@lxorguk.ukuu.org.uk, simon.jeons@gmail.com, ric.masonn@gmail.com Subject: [PATCH v3 001/002] mm: limit growth of 3% hardcoded other user reserve Message-ID: <20130301233208.GA1848@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Limit the growth of the memory reserved for other processes to the smaller of 3% or 2000 pages. This affects OVERCOMMIT_NEVER mode. Signed-off-by: Andrew Shewmaker --- I had simply removed the reserve previously, but that caused forks to fail easily. This allows a user to recover similar to the simple 3% reserve, but allows a single process to allocate more memory. Alan suggested the min(3%, k), and I've k=2000 pages seems to work well. It allows enough free pages to for sshd, bash, and top, in case some sort of recovery is necessary. Of course, memory will still be exhausted eventually. diff --git a/mm/mmap.c b/mm/mmap.c index d1e4124..6134b1d 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -183,9 +183,10 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) allowed += total_swap_pages; /* Don't let a single process grow too big: - leave 3% of the size of this process for other processes */ + * leave the smaller of 3% of the size of this process + * or 2000 pages for other processes */ if (mm) - allowed -= mm->total_vm / 32; + allowed -= min(mm->total_vm / 32, 2000UL); if (percpu_counter_read_positive(&vm_committed_as) < allowed) return 0;