From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757881Ab0JUMyI (ORCPT ); Thu, 21 Oct 2010 08:54:08 -0400 Received: from mail.digidescorp.com ([66.244.163.200]:57805 "EHLO digidescorp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755742Ab0JUMyH (ORCPT ); Thu, 21 Oct 2010 08:54:07 -0400 X-Spam-Processed: digidescorp.com, Thu, 21 Oct 2010 07:54:05 -0500 X-Authenticated-Sender: steve@digidescorp.com X-Return-Path: prvs=191030265f=steve@digidescorp.com X-Envelope-From: steve@digidescorp.com X-MDaemon-Deliver-To: linux-kernel@vger.kernel.org From: "Steven J. Magnani" To: linux-mm@kvack.org Cc: dhowells@redhat.com, linux-kernel@vger.kernel.org, "Steven J. Magnani" Subject: [PATCH] nommu: yield CPU periodically while disposing large VM Date: Thu, 21 Oct 2010 07:53:55 -0500 Message-Id: <1287665635-7925-1-git-send-email-steve@digidescorp.com> X-Mailer: git-send-email 1.6.0.6 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Depending on processor speed, page size, and the amount of memory a process is allowed to amass, cleanup of a large VM may freeze the system for many seconds. This can result in a watchdog timeout. Make sure other tasks receive some service when cleaning up large VMs. Signed-off-by: Steven J. Magnani --- diff -uprN a/mm/nommu.c b/mm/nommu.c --- a/mm/nommu.c 2010-10-21 07:42:23.000000000 -0500 +++ b/mm/nommu.c 2010-10-21 07:46:50.000000000 -0500 @@ -1656,6 +1656,7 @@ SYSCALL_DEFINE2(munmap, unsigned long, a void exit_mmap(struct mm_struct *mm) { struct vm_area_struct *vma; + unsigned long next_yield = jiffies + HZ; if (!mm) return; @@ -1668,6 +1669,11 @@ void exit_mmap(struct mm_struct *mm) mm->mmap = vma->vm_next; delete_vma_from_mm(vma); delete_vma(mm, vma); + /* Yield periodically to prevent watchdog timeout */ + if (time_after(jiffies, next_yield)) { + cond_resched(); + next_yield = jiffies + HZ; + } } kleave("");