Messages in this thread Patch in this message | | | Date | Tue, 09 Apr 2002 23:52:53 -0700 | From | Andrew Morton <> | Subject | [patch] use pdflush for unused inode writeback |
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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) - - 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/
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