From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030191Ab2CTNVa (ORCPT ); Tue, 20 Mar 2012 09:21:30 -0400 Received: from mail-pz0-f46.google.com ([209.85.210.46]:63920 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753229Ab2CTNV2 (ORCPT ); Tue, 20 Mar 2012 09:21:28 -0400 From: Kautuk Consul To: David Howells , Koichi Yasutake Cc: linux-am33-list@redhat.com, linux-kernel@vger.kernel.org, Kautuk Consul Subject: [PATCH 06/20] mn10300/mm/fault.c: Port OOM changes to do_page_fault Date: Tue, 20 Mar 2012 09:20:54 -0400 Message-Id: <1332249654-2747-1-git-send-email-consul.kautuk@gmail.com> X-Mailer: git-send-email 1.7.5.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit d065bd810b6deb67d4897a14bfe21f8eb526ba99 (mm: retry page fault when blocking on disk transfer) and commit 37b23e0525d393d48a7d59f870b3bc061a30ccdb (x86,mm: make pagefault killable) The above commits introduced changes into the x86 pagefault handler for making the page fault handler retryable as well as killable. These changes reduce the mmap_sem hold time, which is crucial during OOM killer invocation. Port these changes to mn10300. Signed-off-by: Kautuk Consul --- arch/mn10300/mm/fault.c | 30 +++++++++++++++++++++++++----- 1 files changed, 25 insertions(+), 5 deletions(-) diff --git a/arch/mn10300/mm/fault.c b/arch/mn10300/mm/fault.c index 0945409..f5111a1 100644 --- a/arch/mn10300/mm/fault.c +++ b/arch/mn10300/mm/fault.c @@ -125,6 +125,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long fault_code, unsigned long page; siginfo_t info; int write, fault; + unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; #ifdef CONFIG_GDBSTUB /* handle GDB stub causing a fault */ @@ -171,6 +172,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long fault_code, if (in_atomic() || !mm) goto no_context; +retry: down_read(&mm->mmap_sem); vma = find_vma(mm, address); @@ -234,6 +236,7 @@ good_area: if (!(vma->vm_flags & VM_WRITE)) goto bad_area; write++; + flags |= FAULT_FLAG_WRITE; break; /* read from protected page */ @@ -252,7 +255,11 @@ good_area: * make sure we exit gracefully rather than endlessly redo * the fault. */ - fault = handle_mm_fault(mm, vma, address, write ? FAULT_FLAG_WRITE : 0); + fault = handle_mm_fault(mm, vma, address, flags); + + if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + return; + if (unlikely(fault & VM_FAULT_ERROR)) { if (fault & VM_FAULT_OOM) goto out_of_memory; @@ -260,10 +267,23 @@ good_area: goto do_sigbus; BUG(); } - if (fault & VM_FAULT_MAJOR) - current->maj_flt++; - else - current->min_flt++; + if (flags & FAULT_FLAG_ALLOW_RETRY) { + if (fault & VM_FAULT_MAJOR) + current->maj_flt++; + else + current->min_flt++; + if (fault & VM_FAULT_RETRY) { + flags &= ~FAULT_FLAG_ALLOW_RETRY; + + /* + * No need to up_read(&mm->mmap_sem) as we would + * have already released it in __lock_page_or_retry + * in mm/filemap.c. + */ + + goto retry; + } + } up_read(&mm->mmap_sem); return; -- 1.7.5.4