From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 10 Apr 2002 02:52:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 10 Apr 2002 02:52:57 -0400 Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:40971 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id ; Wed, 10 Apr 2002 02:52:56 -0400 Message-ID: <3CB3E145.BDBC6124@zip.com.au> Date: Tue, 09 Apr 2002 23:52:53 -0700 From: Andrew Morton X-Mailer: Mozilla 4.79 [en] (X11; U; Linux 2.4.19-pre5 i686) X-Accept-Language: en MIME-Version: 1.0 To: lkml Subject: [patch] use pdflush for unused inode writeback Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org This is pdflush's first application! The writeback of the unused inodes list by keventd is removed, and a pdflush thread is dispatched instead. There is a need for exclusion - to prevent all the pdflush threads from working against the same request queue. This is implemented locally. And this is a problem, because other pdflush threads can be dispatched to writeback other filesystem objects, and they don't know that there's already a pdflush thread working that request queue. So moving the exclusion into the request queue itself is on my things-to-do-list. But the code as-is works OK - under a `dbench 100' load the number of pdflush instances can grow as high as four or five. Some fine tuning is needed... Patch is against 2.5.8-pre3+ratcache+readahead+pageprivate+pdflush --- 2.5.8-pre3/fs/inode.c~dallocbase-45-pdflush_inodes Tue Apr 9 22:53:11 2002 +++ 2.5.8-pre3-akpm/fs/inode.c Tue Apr 9 22:53:11 2002 @@ -433,7 +433,7 @@ void sync_inodes(void) } } -static void try_to_sync_unused_inodes(void * arg) +static void try_to_sync_unused_inodes(unsigned long pexclusive) { struct super_block * sb; int nr_inodes = inodes_stat.nr_unused; @@ -450,10 +450,9 @@ static void try_to_sync_unused_inodes(vo } spin_unlock(&sb_lock); spin_unlock(&inode_lock); + clear_bit(0, (unsigned long *)pexclusive); } -static struct tq_struct unused_inodes_flush_task; - /** * write_inode_now - write an inode to disk * @inode: inode to write to disk @@ -746,8 +745,15 @@ void prune_icache(int goal) * from here or we're either synchronously dogslow * or we deadlock with oom. */ - if (goal) - schedule_task(&unused_inodes_flush_task); + if (goal) { + static unsigned long exclusive; + + if (!test_and_set_bit(0, &exclusive)) { + if (pdflush_operation(try_to_sync_unused_inodes, + (unsigned long)&exclusive)) + clear_bit(0, &exclusive); + } + } } /* * This is called from kswapd when we think we need some @@ -1173,8 +1179,6 @@ void __init inode_init(unsigned long mem NULL); if (!inode_cachep) panic("cannot create inode slab cache"); - - unused_inodes_flush_task.routine = try_to_sync_unused_inodes; } static inline void do_atime_update(struct inode *inode) -