From: Linus Torvalds <[EMAIL PROTECTED]> Date: Fri, 20 Oct 2006 15:02:39 -0700 (PDT)
> On Fri, 20 Oct 2006, Ralf Baechle wrote: > > When I delete the call (not part of my patchset) it means 12% faster > > fork. But I'm not proposing this for 2.6.19. > > I just suspect it means a _buggy_ fork. > > It so happens (I think), that fork is big enough that it probably flushes > the L1 cache _anyway_. My understanding is that this works because in Ralf's original patch (which is the context in which he is removing the flush_cache_mm() call), he uses kmap()/kunmap() to map the page(s) being accessed at a kernel virtual address which will fall into the same cache color as the user virtual address --> no alias problems. Since he does this for every page touched on the kernel side during dup_mmap(), the existing flush_cache_mm() call in dup_mmap() does in fact become redundant. - To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
