From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with ESMTP id 954306B002D for ; Tue, 8 Nov 2011 15:02:51 -0500 (EST) Received: from /spool/local by e23smtp03.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 8 Nov 2011 19:57:56 +1000 Received: from d23av02.au.ibm.com (d23av02.au.ibm.com [9.190.235.138]) by d23relay04.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id pA8JwFMN2154706 for ; Wed, 9 Nov 2011 06:58:23 +1100 Received: from d23av02.au.ibm.com (loopback [127.0.0.1]) by d23av02.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id pA8K1CBm007532 for ; Wed, 9 Nov 2011 07:01:13 +1100 Message-ID: <4EB98A83.3040101@linux.vnet.ibm.com> Date: Wed, 09 Nov 2011 01:31:07 +0530 From: "Srivatsa S. Bhat" MIME-Version: 1.0 Subject: Re: [PATCH] thp: reduce khugepaged freezing latency References: <4EB8E969.6010502@suse.cz> <1320766151-2619-1-git-send-email-aarcange@redhat.com> <1320766151-2619-2-git-send-email-aarcange@redhat.com> In-Reply-To: <1320766151-2619-2-git-send-email-aarcange@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrea Arcangeli Cc: "Rafael J. Wysocki" , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, Jiri Slaby , linux-mm@kvack.org, Andrew Morton On 11/08/2011 08:59 PM, Andrea Arcangeli wrote: > Lack of set_freezable_with_signal() prevented khugepaged to be waken > up (and prevented to sleep again) across the > schedule_timeout_interruptible() calls after freezing() becomes > true. The tight loop in khugepaged_alloc_hugepage() also missed one > try_to_freeze() call in case alloc_hugepage() would repeatedly fail in > turn preventing the loop to break and to reach the try_to_freeze() in > the khugepaged main loop. > > khugepaged would still freeze just fine by trying again the next > minute but it's better if it freezes immediately. > > Reported-by: Jiri Slaby > Signed-off-by: Andrea Arcangeli > --- > mm/huge_memory.c | 3 ++- > 1 files changed, 2 insertions(+), 1 deletions(-) > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 4298aba..67311d1 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -2277,6 +2277,7 @@ static struct page *khugepaged_alloc_hugepage(void) > if (!hpage) { > count_vm_event(THP_COLLAPSE_ALLOC_FAILED); > khugepaged_alloc_sleep(); > + try_to_freeze(); > } else > count_vm_event(THP_COLLAPSE_ALLOC); > } while (unlikely(!hpage) && > @@ -2331,7 +2332,7 @@ static int khugepaged(void *none) > { > struct mm_slot *mm_slot; > > - set_freezable(); > + set_freezable_with_signal(); > set_user_nice(current, 19); > > /* serialize with start_khugepaged() */ > Why do we need to use both set_freezable_with_signal() and an additional try_to_freeze()? Won't just using either one of them be good enough? Or am I missing something here? Thanks, Srivatsa S. Bhat -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org