This series contains the initial writeback tracing patches from Jens, as well as the extensions I added to provide visibility into writeback control structures as the are used by the writeback code. The visibility given is sufficient to understand what is happening in the writeback path - what path is writing data, what path is blocking on congestion, etc, and to determine the differences in behaviour for different sync modes and calling contexts. This tracing really needs to be integrated into mainline so that anyone can improve the tracing as they use it to track down problems in our convoluted writeback paths. The remaining patches are fixes to problems that the new tracing highlighted. Version 3: - added comment to tracepoint creation to explain the unusual placement of the tracepoint header file include. - separated out ->writepage tracepoint addition into it's own patch. - dropped ext4 write_cache_pages separation as it is now in mainline. - removed ext4 tracing references to wbc->no_nrwrite_index_update as they weren't removed in the write_cache_pages patch in mainline. - fixed commit message for write_cache_pages patch - added more information to commit message for sync hold-off fixup. Version 2: - included ext4 write_cache_pages separation patch from Ted Ts'o. - moved CREATE_TRACE_POINTS into fs-writeback.c as suggested by Christoph Hellwig. - moved include of trace/events/writeback.h until after structure definitions in fs-writeback.c - manually revert changes made to write_cache_pages() in 17bc6c30cf6bfffd816bdc53682dd46fc34a2cf4 that caused the regression. This restores the convention that if the fs writes back more than a single page, it subtracts (nr_written - 1) from wbc->nr_to_write, as suggested by Andrew Morton. - added patch to prevent sync from looping in write_cache_pages chasing a moving tail when an appending write workload is running concurrently with sync. -- 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
