Messages in this thread Patch in this message | | | From | Nathan Zimmer <> | Subject | [RFC] Move the memory_notifier out of the memory_hotplug lock | Date | Wed, 5 Feb 2014 10:29:03 -0600 |
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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 <akpm@linux-foundation.org> cc: Tang Chen <tangchen@cn.fujitsu.com> cc: Wen Congyang <wency@cn.fujitsu.com> cc: Toshi Kani <toshi.kani@hp.com> cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> cc: Xishi Qiu <qiuxishi@huawei.com> cc: Cody P Schafer <cody@linux.vnet.ibm.com> cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> cc: David Rientjes <rientjes@google.com> cc: Jiang Liu <liuj97@gmail.com> Cc: Hedi Berriche <hedi@sgi.com> Cc: Mike Travis <travis@sgi.com> 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
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