Nick Piggin <npiggin@xxxxxxx> writes: > Direct IO can invalidate and sync a lot of pagecache pages in the mapping. A > 4K direct IO will actually try to sync and/or invalidate the pagecache of the > entire file, for example (which might be many GB or TB large). > > Improve this by doing range syncs. Also, memory no longer has to be unmapped > to catch the dirty bits for syncing, as dirty bits would remain coherent due to > dirty mmap accounting. > > This fixes the immediate DM deadlocks when doing direct IO reads to block > device with a mounted filesystem, if only by papering over the problem somewhat > rather than addressing the fsync starvation cases. > > Signed-off-by: Nick Piggin <npiggin@xxxxxxx> Reviewed-by: Jeff Moyer <jmoyer@xxxxxxxxxx> Cheers, Jeff -- 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
