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From: Will Deacon <will.deacon@arm.com>
To: Michal Hocko <mhocko@suse.cz>
Cc: Hugh Dickins <hughd@google.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Hillf Danton <dhillf@gmail.com>,
	Russell King <linux@arm.linux.org.uk>,
	"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>
Subject: Re: [PATCH] mm: hugetlb: flush dcache before returning zeroed huge page to userspace
Date: Thu, 16 Aug 2012 19:32:56 +0100	[thread overview]
Message-ID: <20120816183255.GB19401@mudshark.cambridge.arm.com> (raw)
In-Reply-To: <20120816182015.GC12578@dhcp22.suse.cz>

On Thu, Aug 16, 2012 at 07:20:15PM +0100, Michal Hocko wrote:
> On Thu 16-08-12 17:09:54, Will Deacon wrote:
> > +static inline void arch_clear_hugepage_flags(struct page *page)
> > +{
> > +	flush_dcache_page(page);
> > +}
> > +
> 
> Why do we need the hook for ia64? hugetlb_no_page calls clear_huge_page
> and that one calls flush_dcache_page (via clear_user_page), right?
> The same applies to copy_huge_page for COW.

You're right, these are redundant for ppc and ia64 (although ppc does have a
comment moaning about the flush). Looks like it's just sh and ARM that need to
do anything.

Cheers,

Will

WARNING: multiple messages have this Message-ID (diff)
From: Will Deacon <will.deacon@arm.com>
To: Michal Hocko <mhocko@suse.cz>
Cc: Hugh Dickins <hughd@google.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Hillf Danton <dhillf@gmail.com>,
	Russell King <linux@arm.linux.org.uk>,
	"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>
Subject: Re: [PATCH] mm: hugetlb: flush dcache before returning zeroed huge page to userspace
Date: Thu, 16 Aug 2012 19:32:56 +0100	[thread overview]
Message-ID: <20120816183255.GB19401@mudshark.cambridge.arm.com> (raw)
In-Reply-To: <20120816182015.GC12578@dhcp22.suse.cz>

On Thu, Aug 16, 2012 at 07:20:15PM +0100, Michal Hocko wrote:
> On Thu 16-08-12 17:09:54, Will Deacon wrote:
> > +static inline void arch_clear_hugepage_flags(struct page *page)
> > +{
> > +	flush_dcache_page(page);
> > +}
> > +
> 
> Why do we need the hook for ia64? hugetlb_no_page calls clear_huge_page
> and that one calls flush_dcache_page (via clear_user_page), right?
> The same applies to copy_huge_page for COW.

You're right, these are redundant for ppc and ia64 (although ppc does have a
comment moaning about the flush). Looks like it's just sh and ARM that need to
do anything.

Cheers,

Will

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  reply	other threads:[~2012-08-16 18:33 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-07-04 14:32 [PATCH] mm: hugetlb: flush dcache before returning zeroed huge page to userspace Will Deacon
2012-07-04 14:32 ` Will Deacon
2012-07-05 12:37 ` Hillf Danton
2012-07-05 12:37   ` Hillf Danton
2012-07-05 14:17   ` Will Deacon
2012-07-05 14:17     ` Will Deacon
2012-07-06 13:15     ` Hillf Danton
2012-07-06 13:15       ` Hillf Danton
2012-07-09 12:25 ` Michal Hocko
2012-07-09 12:25   ` Michal Hocko
2012-07-09 14:13   ` Will Deacon
2012-07-09 14:13     ` Will Deacon
2012-07-09 23:57     ` Hugh Dickins
2012-07-09 23:57       ` Hugh Dickins
2012-07-10  9:45       ` Will Deacon
2012-07-10  9:45         ` Will Deacon
2012-07-10 10:42         ` Will Deacon
2012-07-10 10:42           ` Will Deacon
2012-07-11 17:48           ` Will Deacon
2012-07-11 17:48             ` Will Deacon
2012-07-12 11:16             ` Michal Hocko
2012-07-12 11:16               ` Michal Hocko
2012-07-12 11:26               ` James Bottomley
2012-07-12 11:26                 ` James Bottomley
2012-07-12 11:26               ` Will Deacon
2012-07-12 11:26                 ` Will Deacon
2012-07-12 11:57                 ` Michal Hocko
2012-07-12 11:57                   ` Michal Hocko
2012-08-07 16:03                   ` Will Deacon
2012-08-07 16:03                     ` Will Deacon
2012-08-08 16:26                     ` Michal Hocko
2012-08-08 16:26                       ` Michal Hocko
2012-08-16 16:09                       ` Will Deacon
2012-08-16 16:09                         ` Will Deacon
2012-08-16 16:09                         ` Will Deacon
2012-08-16 16:09                         ` Will Deacon
2012-08-16 17:25                         ` Michal Hocko
2012-08-16 17:25                           ` Michal Hocko
2012-08-16 17:34                           ` Will Deacon
2012-08-16 17:34                             ` Will Deacon
2012-08-16 18:06                             ` Michal Hocko
2012-08-16 18:06                               ` Michal Hocko
2012-08-16 18:19                               ` Will Deacon
2012-08-16 18:19                                 ` Will Deacon
2012-08-16 18:20                         ` Michal Hocko
2012-08-16 18:20                           ` Michal Hocko
2012-08-16 18:32                           ` Will Deacon [this message]
2012-08-16 18:32                             ` Will Deacon

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