Re: [PATCH 0/2] ZERO PAGE again v4.

From: KAMEZAWA Hiroyuki
Date: Sun Jul 26 2009 - 18:56:24 EST


Hugh Dickins さんは書きました:
> On Thu, 23 Jul 2009, KAMEZAWA Hiroyuki wrote:
>> On Wed, 22 Jul 2009 17:12:45 -0700
>> Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
>> > On Thu, 23 Jul 2009 08:51:37 +0900
>> > KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:
>> > > On Thu, 16 Jul 2009 18:01:34 +0900
>> > > KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:
>> > > >
>> > > > Rebased onto mm-of-the-moment snapshot 2009-07-15-20-57.
>> > > > And modifeied to make vm_normal_page() eat FOLL_NOZERO, directly.
>> > > >
>> > > > Any comments ?
>
> Sorry, I've been waiting to have something positive to suggest,
> but today still busy with my own issues (handling OOM in KSM).
>
no problems. thank you.

> I do dislike that additional argument to vm_normal_page, and
> feel that's a problem to be solved in follow_page, rather
> than spread to every other vm_normal_page user.
>
Hmm, I'll check whether it's necessary or not agian before v5.

> Does follow_page even need to be using vm_normal_page?
Avoiding it means follow_page() has to handle pte_special().
But yes, all vm_normal_page() users other than get_user_page() uses
__FOLL_NOZERO. I feel it's just "which is cleaner ?" problem.


> Hmm, VM_MIXEDMAP, __get_user_pages doesn't exclude that.
> > I also feel a strong (but not yet fulfilled) urge to check
> all the use_zero_page ignore_zero stuff: which is far from
> self-evident.
>
I'll add comment more, in v5 (if vm_normal_page() still have "flags")

I myself feels I'll have to update this to v6 or v7.

Thank you
-Kame


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