Messages in this thread | | | Subject | RE: [PATCH] Priority Lists for the RT mutex | Date | Mon, 11 Apr 2005 15:31:41 -0700 | From | "Perez-Gonzalez, Inaky" <> |
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>From: Bill Huey (hui) [mailto:bhuey@lnxw.com] > >On Mon, Apr 11, 2005 at 10:57:37AM +0200, Ingo Molnar wrote: >> >> * Perez-Gonzalez, Inaky <inaky.perez-gonzalez@intel.com> wrote: >> >> > Let me re-phrase then: it is a must have only on PI, to make sure you >> > don't have a loop when doing it. Maybe is a consequence of the >> > algorithm I chose. -However- it should be possible to disable it in >> > cases where you are reasonably sure it won't happen (such as kernel >> > code). In any case, AFAIR, I still did not implement it. >> >> are there cases where userspace wants to disable deadlock-detection for >> its own locks? > >I'd disable it for userspace locks. There might be folks that want to >implement userspace drivers, but I can't imagine it being 'ok' to have >the kernel call out to userspace and have it block correctly. I would >expect them to do something else that's less drastic.
If you are exposing the kernel locks to userspace to implement mutexes (eg POSIX mutexes), deadlock checking is a feature you want to have to complain with POSIX. According to some off the record requirements I've been given, some applications badly need it (I have a hard time believing that they are so broken, but heck...).
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