[Drbd-dev] Supporting blktrace in DRBD

Graham, Simon Simon.Graham at stratus.com
Sun Nov 1 23:10:24 CET 2009

I've been using blktrace to investigate performance of DRBD and have
found a few places where DRBD needs to issue blktrace API calls that it
does not - usually, the library routines in ll_rw_blk.c make these calls
on behalf of block devices but those like DRBD that write their own
routines need to also make some trace calls. Specifically, DRBD needs to
trace request completion and calls to lower level unplug routines (it's
hard to be sure but it looks to me like the caller of the unplug routine
is supposed to make the trace call).


Patch against 8.2 (and tested with kernel 2.6.18) attached for your



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