ZERO_PAGE again v5. [LWN.net]

From:		KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
To:		"linux-mm@kvack.org" <linux-mm@kvack.org>
Subject:		[PATCH] ZERO_PAGE again v5.
Date:		Wed, 5 Aug 2009 19:16:43 +0900
Message-ID:		<20090805191643.2b11ae78.kamezawa.hiroyu@jp.fujitsu.com>
Cc:		"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, npiggin@suse.de, hugh.dickins@tiscali.co.uk, "akpm@linux-foundation.org" <akpm@linux-foundation.org>, torvalds@linux-foundation.org
Archive-link:		Article, Thread


Updated from v4 as
  - avoid to add new arguments to vm_normal_page().
    vm_normal_page() always returns NULL if ZERO_PAGE is found.
  - follow_page() directly handles pte_special and ANON_ZERO_PAGE.

Then, amount of changes are reduced. Thanks for advices.

Concerns pointed out:
  - Does use_zero_page() cover all cases ?
    I think yes..
  - All get_user_pages() callers, which may find ZERO_PAGE is safe ?
    need tests.
  - All follow_pages() callers, which may find ZERO_PAGE is safe ?
    I think yes.

Thanks,
-Kame

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/