From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:36096 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2406029AbgFXStn (ORCPT ); Wed, 24 Jun 2020 14:49:43 -0400 Date: Wed, 24 Jun 2020 20:49:30 +0200 From: Gerald Schaefer Subject: Re: [PATCH 18/26] mm/s390: Use general page fault accounting Message-ID: <20200624204930.2445bcd6@thinkpad> In-Reply-To: <20200619161335.9664-1-peterx@redhat.com> References: <20200619160538.8641-1-peterx@redhat.com> <20200619161335.9664-1-peterx@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-s390-owner@vger.kernel.org List-ID: To: Peter Xu Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , Andrea Arcangeli , Will Deacon , Michael Ellerman , Linus Torvalds , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , linux-s390@vger.kernel.org On Fri, 19 Jun 2020 12:13:35 -0400 Peter Xu wrote: > Use the general page fault accounting by passing regs into handle_mm_fault(). > It naturally solve the issue of multiple page fault accounting when page fault > retry happened. > > CC: Heiko Carstens > CC: Vasily Gorbik > CC: Christian Borntraeger > CC: linux-s390@vger.kernel.org > Signed-off-by: Peter Xu > --- > arch/s390/mm/fault.c | 16 +--------------- > 1 file changed, 1 insertion(+), 15 deletions(-) > > diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c > index ab6d7eedcfab..4d62ca7d3e09 100644 > --- a/arch/s390/mm/fault.c > +++ b/arch/s390/mm/fault.c > @@ -479,7 +479,7 @@ static inline vm_fault_t do_exception(struct pt_regs *regs, int access) > * make sure we exit gracefully rather than endlessly redo > * the fault. > */ > - fault = handle_mm_fault(vma, address, flags, NULL); > + fault = handle_mm_fault(vma, address, flags, regs); > if (fault_signal_pending(fault, regs)) { > fault = VM_FAULT_SIGNAL; > if (flags & FAULT_FLAG_RETRY_NOWAIT) > @@ -489,21 +489,7 @@ static inline vm_fault_t do_exception(struct pt_regs *regs, int access) > if (unlikely(fault & VM_FAULT_ERROR)) > goto out_up; There are two cases here where we skipped the accounting, fault_signal_pending() and VM_FAULT_ERROR, similar to other archs. fault_signal_pending() should be ok, because that only seems to be true for fault & VM_FAULT_RETRY, in which case the new approach also skips the accounting. But for VM_FAULT_ERROR, the new approach would do accounting, IIUC. Is that changed on purpose? See also my reply on [PATCH 01/26]. Regards, Gerald