Messages in this thread | | | From | "Metzger, Markus T" <> | Date | Thu, 18 Dec 2008 15:57:53 +0000 | Subject | RE: [rfc] x86, ptrace: memory accounting for branch tracing |
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>-----Original Message----- >From: Andrew Morton [mailto:akpm@linux-foundation.org] >Sent: Dienstag, 16. Dezember 2008 19:18 >To: Ingo Molnar >Cc: Metzger, Markus T; Peter Zijlstra;
>> > Account memory allocated for the BTS buffer to the traced task's >> > total_vm and locked_vm. >> >> Andrew, is this the right (and preferred) way to attach BTS buffer >> allocation overhead to the RLIMIT_MEMLOCK bucket: > >Close. I suspect we could refactor mlock.c to avoid all the code >duplication we have there. > >There's (almost) nothing BTS-specific in this code, and it would be >better if it lived in mm/mlock.c. Hopefully in a >usable-by-other-parts-of-mlock.c fashion.
Thanks,
I added alloc_locked_buffer() and free_locked_buffer() functions to mm/mlock.c.
>> > +static int ptrace_bts_allocate_buffer(struct task_struct >*child, size_t size) >> > +{ >> > + unsigned long rlim, vm, pgsz; >> > + int error = -ENOMEM; >> > + >> > + pgsz = PAGE_ALIGN(size) >> PAGE_SHIFT; >> > + >> > + down_write(&child->mm->mmap_sem); >> > + >> > + rlim = child->signal->rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT; >> > + vm = child->mm->total_vm + pgsz; >> > + if (rlim < vm) > >This is off-by-one, I think. Should be > > if (vm > rmlim) >
Those two should be equivalent, shouldn't they?
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