From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
To: Christophe Leroy <christophe.leroy@c-s.fr>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Scott Wood <oss@buserror.net>
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH 1/5] powerpc/mm: only call store_updates_sp() on stores in do_page_fault()
Date: Mon, 24 Apr 2017 14:40:27 +0530 [thread overview]
Message-ID: <87zif6188s.fsf@skywalker.in.ibm.com> (raw)
In-Reply-To: <22c2ebcfe72f4f17be6d284d922895cec34e23fc.1492606297.git.christophe.leroy@c-s.fr>
Christophe Leroy <christophe.leroy@c-s.fr> writes:
> Function store_updates_sp() checks whether the faulting
> instruction is a store updating r1. Therefore we can limit its calls
> to stores exceptions.
>
> This patch is an improvement of commit a7a9dcd882a67 ("powerpc: Avoid
> taking a data miss on every userspace instruction miss")
>
> With the same microbenchmark app, run with 500 as argument, on an
> MPC885 we get:
>
> Before this patch: 152000 DTLB misses
> After this patch: 147000 DTLB misses
>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
> ---
> arch/powerpc/mm/fault.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
> index 3a7d580fdc59..67fefb59d40e 100644
> --- a/arch/powerpc/mm/fault.c
> +++ b/arch/powerpc/mm/fault.c
> @@ -287,7 +287,7 @@ int do_page_fault(struct pt_regs *regs, unsigned long address,
> * can result in fault, which will cause a deadlock when called with
> * mmap_sem held
> */
> - if (!is_exec && user_mode(regs))
> + if (is_write && user_mode(regs))
> store_update_sp = store_updates_sp(regs);
>
> if (user_mode(regs))
> --
> 2.12.0
next prev parent reply other threads:[~2017-04-24 9:11 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-19 12:56 [PATCH 0/5] powerpc/mm: some cleanup of do_page_fault() Christophe Leroy
2017-04-19 12:56 ` [PATCH 1/5] powerpc/mm: only call store_updates_sp() on stores in do_page_fault() Christophe Leroy
2017-04-24 9:10 ` Aneesh Kumar K.V [this message]
2017-06-05 10:21 ` [1/5] " Michael Ellerman
2017-04-19 12:56 ` [PATCH 2/5] powerpc/mm: split store_updates_sp() in two parts " Christophe Leroy
2017-04-24 9:11 ` Aneesh Kumar K.V
2017-06-02 9:26 ` Michael Ellerman
2017-06-02 9:39 ` Christophe LEROY
2017-06-02 12:11 ` Benjamin Herrenschmidt
2017-06-02 12:31 ` Christophe LEROY
2017-06-05 10:49 ` Michael Ellerman
2017-06-05 10:45 ` Michael Ellerman
2017-06-05 17:48 ` christophe leroy
2017-06-06 11:00 ` Michael Ellerman
2017-06-06 13:29 ` Christophe LEROY
2017-04-19 12:56 ` [PATCH 3/5] powerpc/mm: remove a redundant test " Christophe Leroy
2017-04-19 12:56 ` [PATCH 4/5] powerpc/mm: Evaluate user_mode(regs) only once " Christophe Leroy
2017-04-24 9:13 ` Aneesh Kumar K.V
2017-04-19 12:56 ` [PATCH 5/5] powerpc/mm: The 8xx doesn't call do_page_fault() for breakpoints Christophe Leroy
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