Ping? - Ted On Sun, Jun 05, 2011 at 11:21:13PM -0400, Ted Ts'o wrote: > On Thu, Jun 02, 2011 at 11:54:24AM +0200, Jan Kara wrote: > > What happens is that direct reclaim sometimes does > > wait_on_page_writeback() (e.g. shrink_page_list()) or it explicitely waits > > for NR_WRITEBACK statistics to go below some threshold > > (throttle_vm_writeout()). And that is deadlockable if we hold i_mutex while > > doing this because we may need i_mutex to actually move the page from > > PageWriteback state... > > We don't actully call set_page_writeback() until right before we > submit the page for writeback. And we convert the unwritten extents > in a workqueue, which gets submitted after we call > end_page_writeback(). So I'm still not seeing a problem; sorry if I'm > being dense! > > - Ted > > > As I'm saying this, I've realized ext4 has this problem also with > > stable-pages patches because there we can wait for PageWriteback in > > grab_cache_page_write_begin() when we also hold i_mutex. So I think we'll > > have to come up with a way to convert unwritten extents without having to > > hold i_mutex. That's going to be interesting. > > > > Honza > > -- > > Jan Kara <jack@xxxxxxx> > > SUSE Labs, CR > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > > the body of a message to majordomo@xxxxxxxxxxxxxxx > > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
