On Sat, 2009-03-28 at 11:48 +0100, Peter Zijlstra wrote:
> On Sat, 2009-03-28 at 09:46 +0100, Brice Goglin wrote:
> > Peter Zijlstra wrote:
> > > Also note that doing large gup() with gup_fast() will be undesirable due
> > > to it disabling IRQs. So iterating say several MB worth of pages will
> >
On Thu, 2009-03-26 at 17:43 -0700, Jesse Barnes wrote:
> On Wed, 25 Mar 2009 14:45:05 -0700
> Eric Anholt wrote:
>
> > Since the pagefault path determines that the lock order we use has to
> > be mmap_sem -> struct_mutex, we can't allow page faults to occur
> > while the struct_mutex is held. To
On Fri, 2009-03-27 at 13:10 -0700, Eric Anholt wrote:
> On Fri, 2009-03-27 at 19:10 +0100, Andi Kleen wrote:
> > On Fri, Mar 27, 2009 at 09:36:45AM -0700, Eric Anholt wrote:
> > > > > You are aware that there is a fast path now (get_user_pages_fast)
> > > > > which
> > > > > is significantly faste
On Sat, 2009-03-28 at 01:58 +0100, Peter Zijlstra wrote:
> > OK. I'm not too excited here -- 10% of 2% of the CPU time doesn't get
> > me to the 10% loss that the slow path added up to. Most of the cost is
> > in k{un,}map_atomic of the returned pages.
>
> Also note that doing large gup() wit
On Sat, 2009-03-28 at 13:22 +0100, Peter Zijlstra wrote:
> I'm not really trusting my brain today, but something like the below
> should work I think.
>
> Nick, any thoughts?
>
> Not-Signed-off-by: Peter Zijlstra
> ---
> arch/x86/mm/gup.c | 24 +---
> 1 files changed, 21
Peter Zijlstra wrote:
> Also note that doing large gup() with gup_fast() will be undesirable due
> to it disabling IRQs. So iterating say several MB worth of pages will
> hurt like crazy. Currently all gup_fast() users do a single page lookup.
>
In 2.6.29, fs/bio.c:955, fs/direct-io.c:153 and f
On Sat, 2009-03-28 at 09:46 +0100, Brice Goglin wrote:
> Peter Zijlstra wrote:
> > Also note that doing large gup() with gup_fast() will be undesirable due
> > to it disabling IRQs. So iterating say several MB worth of pages will
> > hurt like crazy. Currently all gup_fast() users do a single page
