On Thu, May 05, 2011 at 05:00:59AM +0800, Jan Kara wrote: > On Mon 02-05-11 11:17:51, Wu Fengguang wrote: > > sync(2) is performed in two stages: the WB_SYNC_NONE sync and the > > WB_SYNC_ALL sync. Tag the first stage with wbc.tagged_sync and do > > livelock prevention for it, too. > > > > Note that writeback_inodes_sb() is called by not only sync(), they are > > treated the same because the other callers need also need livelock > > prevention. > I was thinking about this and could not find any - which other callers > of writeback_inodes_sb() need the livelock prevention? For example, the writeback_inodes_sb_if_idle() call from ext4. In general anyone that pass get_nr_dirty_pages() as work->nr_pages may be highly over-estimating the work set. It won't be directly livelocked since ext4 won't wait for completion, however there is possibility the works queued behind are delayed and livelocked. Ideally simple ->nr_pages works should be given lower priority and even may be merged with each other, and that would be future work. Thanks, Fengguang -- 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
