From: catalin.marinas@arm•com (Catalin Marinas)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH V3 2/2] ARM: Handle user space mapped pages in flush_kernel_dcache_page
Date: Wed, 8 May 2013 16:08:00 +0100 [thread overview]
Message-ID: <20130508150800.GI2703@arm.com> (raw)
In-Reply-To: <CACVXFVPOuabwAa1VDmSnfDG=M-1Df02_kpbm0UVAVctCAB-U4Q@mail.gmail.com>
On Sat, May 04, 2013 at 09:21:27AM +0100, Ming Lei wrote:
> On Fri, May 3, 2013 at 6:02 PM, Catalin Marinas <catalin.marinas@arm•com> wrote:
> >>
> >> I assume that you inhibited the call to flush_dcache_page() in
> >> __get_user_pages() for anon pages. Otherwise, you will be flooded
> >> with warnings.
> >
> > I haven't done any stress testing so I don't think I hit this code path,
> > so no warning. But yes, it should have triggered. Anyway, in this case
> > flush_dcache_page() should have just ignored (clearing PG_arch_1 is
> > harmless anyway if we also ignore this bit in __sync_icache_dcache for
> > non-aliasing caches).
>
> Yes, maybe we can do a little optimization for O_DIRECT since no
> dcache alias and I/D coherency problem in this case on ARMv7, how
> about below change?
>
> diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c
> index 1c8f7f5..962a657 100644
> --- a/arch/arm/mm/flush.c
> +++ b/arch/arm/mm/flush.c
> @@ -287,6 +287,8 @@ void flush_dcache_page(struct page *page)
> mapping && !mapping_mapped(mapping))
> clear_bit(PG_dcache_clean, &page->flags);
> else {
> + if (!mapping && cache_is_vipt_nonaliasing())
> + return;
> __flush_dcache_page(mapping, page);
> if (mapping && cache_is_vivt())
> __flush_dcache_aliases(mapping, page);
I wonder whether we could move the:
if (!mapping)
return
at the top of this function, IOW don't touch any anonymous pages. Would
anything be broken (apart from wrong API use)?
--
Catalin
next prev parent reply other threads:[~2013-05-08 15:08 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-07 11:29 [PATCH V2 0/2] fix and improvement of flush(_kernel)_dcache_page() Simon Baatz
2012-10-07 11:29 ` [PATCH V2 1/2] ARM: remove unnecessary flush of anon pages in flush_dcache_page() Simon Baatz
2012-10-08 11:36 ` Catalin Marinas
2012-10-08 17:38 ` Simon Baatz
2012-10-08 17:43 ` Catalin Marinas
2012-10-07 11:29 ` [PATCH V3 2/2] ARM: Handle user space mapped pages in flush_kernel_dcache_page Simon Baatz
2012-10-08 17:44 ` Catalin Marinas
2012-10-08 20:02 ` Simon Baatz
2012-10-08 20:20 ` Russell King - ARM Linux
2012-10-08 23:07 ` Simon Baatz
2012-11-18 21:10 ` Jason Cooper
2013-04-18 11:16 ` Jason Cooper
2013-04-18 11:22 ` Russell King - ARM Linux
2013-04-18 11:40 ` Jason Cooper
2013-04-18 13:51 ` Catalin Marinas
2013-04-21 22:06 ` Simon Baatz
2013-04-30 11:22 ` Catalin Marinas
2013-04-30 21:04 ` Simon Baatz
2013-05-01 14:22 ` Catalin Marinas
2013-05-01 19:04 ` Simon Baatz
2013-05-02 9:54 ` Catalin Marinas
2013-05-02 19:38 ` Simon Baatz
2013-05-03 10:02 ` Catalin Marinas
2013-05-04 8:21 ` Ming Lei
2013-05-08 15:08 ` Catalin Marinas [this message]
2013-05-08 18:43 ` Russell King - ARM Linux
2013-05-08 19:31 ` Simon Baatz
2013-05-08 21:13 ` Catalin Marinas
2013-05-09 1:52 ` Ming Lei
2013-05-11 6:27 ` Simon Baatz
2013-05-13 3:12 ` Ming Lei
2013-05-05 22:26 ` Simon Baatz
2013-05-08 15:28 ` Catalin Marinas
2013-04-18 19:39 ` Simon Baatz
2013-04-18 19:00 ` Simon Baatz
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