On Fri, Sep 04 2009, Christoph Hellwig wrote: > On Fri, Sep 04, 2009 at 08:53:57AM +0200, Jens Axboe wrote: > > > + if (wbc->sync_mode == WB_SYNC_ALL) > > > + bdi_wait_on_work_clear(&work); > > > } > > > > That doesn't work, you have to wait for on-stack work. So either we just > > punt and not do anything for WB_SYNC_NONE if the allocation fails, or we > > punt to stack and do the wait. Since it's a cleaning action and > > allocation fails, falling back to the stack and waiting seems like the > > most appropriate choice. > > True, the wait needs to be unconditional. Updated version below. (did you forget that patch? it's not there). > But now that I look at it, I wonder if we should even bother with it. > bdi_start_writeback is only used in WC_SYNC_NONE mode in > balance_dirty_pages. So if we really run so much out of memory that we > can't allocate the bdi_work we might just throttle and wait for the > flusher thread to do it's work. That would get rid of all the > special cases for the on-stack bdi_work instances. Dunno, it feels a lot saner to always block there and ensure that we get the message across. -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
