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Date: Thu, 5 Jul 2012 15:17:00 +0100 From: Will Deacon <will.deacon@....com> To: Hillf Danton <dhillf@...il.com> Cc: "linux-mm@...ck.org" <linux-mm@...ck.org>, "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>, "mhocko@...e.cz" <mhocko@...e.cz>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org> Subject: Re: [PATCH] mm: hugetlb: flush dcache before returning zeroed huge page to userspace On Thu, Jul 05, 2012 at 01:37:46PM +0100, Hillf Danton wrote: > On Wed, Jul 4, 2012 at 10:32 PM, Will Deacon <will.deacon@....com> wrote: > > When allocating and returning clear huge pages to userspace as a > > response to a fault, we may zero and return a mapping to a previously > > dirtied physical region (for example, it may have been written by > > a private mapping which was freed as a result of an ftruncate on the > > backing file). On architectures with Harvard caches, this can lead to > > I/D inconsistency since the zeroed view may not be visible to the > > instruction stream. > > > > This patch solves the problem by flushing the region after allocating > > and clearing a new huge page. Note that PowerPC avoids this issue by > > performing the flushing in their clear_user_page implementation to keep > > the loader happy, however this is closely tied to the semantics of the > > PG_arch_1 page flag which is architecture-specific. > > > > Acked-by: Catalin Marinas <catalin.marinas@....com> > > Signed-off-by: Will Deacon <will.deacon@....com> > > --- > > Thanks:) > > Acked-by: Hillf Danton <dhillf@...il.com> Thanks Hillf. Which tree does this stuff usually go through? Will -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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