On Thu, Feb 25, 2010 at 09:20:35AM +0100, Jens Axboe wrote: > On Wed, Feb 24 2010, Alan Stern wrote: > > On Wed, 24 Feb 2010, Jens Axboe wrote: > > > > > > > But if you wanted, I guess the only way would be to lookup > > > > > dirty/writeback pages on the bdev inode mapping. For that you'd need the > > > > > bdev, not the gendisk or the queue though. > > > > > > > > I can get the bdev from the gendisk by calling bdget_disk() with a > > > > partition number of 0, right? What would the next step be? Would this > > > > check for dirty pages associated with any of the partitions or would it > > > > only look at pages associated with the inode for the entire disk? > > > > > > It would cover the entire bdev. > > > > Okay, so once I've got the bdev, how do I look up the dirty/writeback > > pages on the inode mapping? > > I _think_ you can get away with not doing a radix lookup for dirty > pages, just looking at the BDI_RECLAIMABLE stat on the bdi. That would > be: > > bdi_stat(bdev->bd_inode->i_mapping->backing_dev_info, BDI_RECLAIMABLE); mapping_tagged(bdev->bd_inode->i_mapping, PAGECACHE_TAG_DIRTY); is about as low overhead as it gets as the radix tree propagateѕ tags back up to the root. i.e. no page lookups needed at all to determine if it is dirty. Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
