|| ||Namhyung Kim <email@example.com> |
|| ||Jens Axboe <firstname.lastname@example.org> |
|| ||[PATCH v2 0/3] blktrace: bio-based device tracing improvement |
|| ||Sun, 4 Sep 2011 22:15:09 +0900|
|| ||email@example.com, firstname.lastname@example.org|
|| ||Article, Thread
The blktrace is used to report block device activities to user space
using kernel tracepoint but it was focused to block I/O request struct.
Thus bio-based devices (i.e. loop, ram, md, ...) which don't make use
of the request structure could not be supported well - the tool only
can detect a limited number of events such as queuing, cloning and
remapping but it cannot know when the I/O activity is completed.
bio_endio(), the I/O completion callback, can be used to fix this
problem by adding appropriate tracepoint in it. However it was called
from other paths too (normal request-based block devices and some of
nested block I/O handling routines) so that we should recognize such
cases to prevent duplicated reports. In this series, BIO_IN_FLIGHT flag
is introduced and used for that purpose.
Note that (bio-based) dm already supported completion report by adding
the tracepoint into the path manually. With this patches, it will be
converted to use generic mechanism.
Changes from v1:
* kill __bio_endio()
* use BIO_IN_FLIGHT flag
Any feedbacks are welcome.
Namhyung Kim (3):
block: move trace_block_bio_remap() before blk_partition_remap
block: introduce BIO_IN_FLIGHT flag
block: don't export block_bio_complete tracepoint
block/blk-core.c | 12 ++++++++----
drivers/md/dm.c | 1 -
fs/bio.c | 9 +++++++++
include/linux/blk_types.h | 1 +
4 files changed, 18 insertions(+), 5 deletions(-)
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