RE: [patch 1/2] x86, ptrace: support pebs in ds.c

From: Metzger, Markus T
Date: Fri Feb 22 2008 - 05:14:57 EST


>-----Original Message-----
>From: Ingo Molnar [mailto:mingo@xxxxxxx]
>Sent: Freitag, 22. Februar 2008 10:53
>To: Metzger, Markus T

>> The ptrace API is the user interface for the debugging/BTS aspect of
>> it. As such, it will remain stable.
>
>your last patch does this to arch/x86/kernel/ptrace.c:
>
> 266 insertions(+), 174 deletions(-)
>
>doesnt that change the ptrace bits and the ptrace API semantics?

The last patch does change the ptrace API - before it becomes public.

After it becomes public, ds.c can be changed without affecting the
ptrace API.


The last changes are not strictly necessary - I could as well implement
the old interface. If there are objections to or concerns regarding
those API changes, I will do just that. The changes are:
- add PTRACE_BTS_O_ALLOC to explicitly request reallocation of the BTS
buffer.
This used to be implicit when the size changes.
- remove PTRACE_BTS_O_CUT_SIZE
This used to reduce the size requested for the BTS buffer to the
maximal available size, if necessary.
I do not think this is necessary. Users should check their ulimits.

This is what I meant with ironing out the ptrace API.


thanks and regards,
markus.
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