Messages in this thread | | | Date | Thu, 27 May 2010 04:02:10 -0700 | From | Michel Lespinasse <> | Subject | Re: [PATCH 00/11] V4: rwsem changes + down_read_critical() proposal |
| |
On Wed, May 26, 2010 at 10:23:59AM +0900, KAMEZAWA Hiroyuki wrote: > On Tue, 25 May 2010 11:27:55 +0200 > Peter Zijlstra <peterz@infradead.org> wrote: > > Also, do you really think doing something like: > > > > /* > > * Check the vma index is within the range and do > > * sequential scan until m_index. > > */ > > vma = NULL; > > if ((unsigned long)l < mm->map_count) { > > vma = mm->mmap; > > while (l-- && vma) > > vma = vma->vm_next; > > goto out; > > } > > > > with preemption disabled is a _good_ thing? > > > > People were talking about raising our vma limit of 64k...
All right, this is clearly a problem then.
> Hmm..can't we use something speculative lookup for reading maps ? > (as we played in several months ago...)
Would you happen to have a link to that conversation / remember the subject line of the thread ?
Thanks,
-- Michel "Walken" Lespinasse A program is never fully debugged until the last user dies.
| |