Messages in this thread | | | Date | Mon, 8 Apr 2013 06:52:53 -0400 | From | "Frank Ch. Eigler" <> | Subject | Re: Excessive stall times on ext4 in 3.9-rc2 |
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Hi, Mel -
> > [...] git kernel developers > > should use git systemtap, as has always been the case. [...] > > At one point in the past this used to be the case but then systemtap had to > be compiled as part of automated tests across different kernel versions. It > could have been worked around in various ways or even installed manually > when machines were deployed but stap-fix.sh generally took less time to > keep working.
OK, if that works for you. Keep in mind though that newer versions of systemtap retain backward-compatibility for ancient versions of the kernel, so git systemtap should work on those older versions just fine.
> [...] > Yes, this was indeed the problem. The next version of watch-dstate.pl > treated get_request_wait() as a function that may or may not exist. It > uses /proc/kallsyms to figure it out.
... or you can use the "?" punctuation in the script to have systemtap adapt:
probe kprobe.function("get_request_wait") ? { ... }
- FChE
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