Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752966AbaBEQ3M (ORCPT ); Wed, 5 Feb 2014 11:29:12 -0500 Received: from relay2.sgi.com ([192.48.179.30]:55488 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752672AbaBEQ3K (ORCPT ); Wed, 5 Feb 2014 11:29:10 -0500 From: Nathan Zimmer To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Nathan Zimmer , Andrew Morton , Tang Chen , Wen Congyang , Toshi Kani , Yasuaki Ishimatsu , Xishi Qiu , Cody P Schafer , "Rafael J. Wysocki" , David Rientjes , Jiang Liu , Hedi Berriche , Mike Travis Subject: [RFC] Move the memory_notifier out of the memory_hotplug lock Date: Wed, 5 Feb 2014 10:29:03 -0600 Message-Id: <1391617743-150518-1-git-send-email-nzimmer@sgi.com> X-Mailer: git-send-email 1.8.2.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org There are a few spots where we call memory_notifier. This doesn't need to be done under lock since memory_notify is just a blocking_notifier_call_chain with it's own locking mechanism. This RFC is a follow on to the one I submitted earlier. (move register_memory_resource out of the lock_memory_hotplug, commit ac13c46) Most of our time is being spend under the memory hotplug lock in particular online_pages() so it makes sense to move out everything that can be easily moved out. However perf pointed me to a spot to work on, setup_zone_migrate_reserve. In fact most of the time is spent there. Since that is going to require more reading and time I will start by whittling out some easy pieces. cc: Andrew Morton cc: Tang Chen cc: Wen Congyang cc: Toshi Kani cc: Yasuaki Ishimatsu cc: Xishi Qiu cc: Cody P Schafer cc: "Rafael J. Wysocki" cc: David Rientjes cc: Jiang Liu Cc: Hedi Berriche Cc: Mike Travis linux-mm@kvack.org (open list:MEMORY MANAGEMENT) linux-kernel@vger.kernel.org (open list) --- mm/memory_hotplug.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 62a0cd1..a3cbd14 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -985,12 +985,12 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ if (need_zonelists_rebuild) zone_pcp_reset(zone); mutex_unlock(&zonelists_mutex); + unlock_memory_hotplug(); printk(KERN_DEBUG "online_pages [mem %#010llx-%#010llx] failed\n", (unsigned long long) pfn << PAGE_SHIFT, (((unsigned long long) pfn + nr_pages) << PAGE_SHIFT) - 1); memory_notify(MEM_CANCEL_ONLINE, &arg); - unlock_memory_hotplug(); return ret; } @@ -1016,9 +1016,10 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ writeback_set_ratelimit(); + unlock_memory_hotplug(); + if (onlined_pages) memory_notify(MEM_ONLINE, &arg); - unlock_memory_hotplug(); return 0; } @@ -1601,8 +1602,8 @@ repeat: vm_total_pages = nr_free_pagecache_pages(); writeback_set_ratelimit(); - memory_notify(MEM_OFFLINE, &arg); unlock_memory_hotplug(); + memory_notify(MEM_OFFLINE, &arg); return 0; failed_removal: -- 1.8.2.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/