From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx110.postini.com [74.125.245.110]) by kanga.kvack.org (Postfix) with SMTP id 5637F6B015F for ; Wed, 29 May 2013 14:45:13 -0400 (EDT) Received: from itwm2.itwm.fhg.de (itwm2.itwm.fhg.de [131.246.191.3]) by mailgw1.uni-kl.de (8.14.3/8.14.3/Debian-9.4) with ESMTP id r4TIj79D016532 (version=TLSv1/SSLv3 cipher=EDH-RSA-DES-CBC3-SHA bits=168 verify=NOT) for ; Wed, 29 May 2013 20:45:08 +0200 Received: from mail2.itwm.fhg.de ([131.246.191.79]:59990) by itwm2.itwm.fhg.de with esmtps (TLSv1:DES-CBC3-SHA:168) (/C=DE/ST=Rheinland-Pfalz/L=Kaiserslautern/O=Fraunhofer ITWM/OU=SLG/CN=mail2.itwm.fhg.de)(verified=1) (Exim 4.74 #1) id 1UhlMx-0004yM-1B for linux-mm@kvack.org; Wed, 29 May 2013 20:45:07 +0200 Message-ID: <51A64CB2.9070503@itwm.fraunhofer.de> Date: Wed, 29 May 2013 20:45:06 +0200 From: Bernd Schubert MIME-Version: 1.0 Subject: spin_lock contention in shrink_inactive_list Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org Hi all, we got a report about a system where fhgfs has a rather high latency (fhgfs is running on top of xfs) and while investigating the system I noticed that the system was rather cpu bound. I'm not sure, but somehow CPU usage went down after disabling swap. Is the lock contention a known issue? kernel version: 3.8.2 > spin_lock > # Overhead Command Shared Object Symbol > # ........ ............... ............................................................................................. .............................................................................................................................. > # > 63.93% fhgfs-storage/M [kernel.kallsyms] 0xffffffff815d31bd k [k] _raw_spin_lock_irq > | > --- _raw_spin_lock_irq > | > |--99.44%-- shrink_inactive_list > | shrink_lruvec > | shrink_zone > | shrink_zones > | do_try_to_free_pages > | try_to_free_pages > | __alloc_pages_slowpath > | __alloc_pages_nodemask > | | > | |--99.98%-- alloc_pages_current > | | | > | | |--100.00%-- __page_cache_alloc > | | | | > | | | |--100.00%-- grab_cache_page_write_begin > | | | | xfs_vm_write_begin > | | | | generic_perform_write > | | | | generic_file_buffered_write > | | | | xfs_file_buffered_aio_write > | | | | xfs_file_aio_write > | | | | do_sync_write > | | | | vfs_write > | | | | sys_write > | | | | system_call_fastpath > | | | | 0x2aaaaba8f4ed > | | | --0.00%-- [...] > | | --0.00%-- [...] > | --0.02%-- [...] > --0.56%-- [...] > > 3.73% fhgfs-storage/M [kernel.kallsyms] 0xffffffff815d3533 k [k] _raw_spin_lock_irqsave > | > --- _raw_spin_lock_irqsave > | > |--97.82%-- pagevec_lru_move_fn > | | > | |--91.28%-- __pagevec_lru_add > | | | > | | |--86.17%-- __lru_cache_add > | | | add_to_page_cache_lru > | | | grab_cache_page_write_begin > | | | xfs_vm_write_begin > | | | generic_perform_write > | | | generic_file_buffered_write > | | | xfs_file_buffered_aio_write > | | | xfs_file_aio_write > | | | do_sync_write > | | | vfs_write Thanks, Bernd -- 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/ . Don't email: email@kvack.org