From: Leonardo Bras <leonardo@linux.ibm.com>
To: John Hubbard <jhubbard@nvidia.com>,
linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
Linux-MM <linux-mm@kvack.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Arnd Bergmann <arnd@arndb.de>,
Richard Fontana <rfontana@redhat.com>,
Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>,
YueHaibing <yuehaibing@huawei.com>,
Nicholas Piggin <npiggin@gmail.com>,
Mike Rapoport <rppt@linux.ibm.com>,
Keith Busch <keith.busch@intel.com>,
Jason Gunthorpe <jgg@ziepe.ca>, Paul Mackerras <paulus@samba.org>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Ganesh Goudar <ganeshgr@linux.ibm.com>,
Dan Williams <dan.j.williams@intel.com>,
Ira Weiny <ira.weiny@intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Allison Randal <allison@lohutok.net>
Subject: Re: [PATCH v2 11/11] powerpc/mm/book3s64/pgtable: Uses counting method to skip serializing
Date: Mon, 23 Sep 2019 17:23:03 -0300 [thread overview]
Message-ID: <c64d34118542d5c2d31b8f6b7802d2a29dac71ef.camel@linux.ibm.com> (raw)
In-Reply-To: <1568b3ef-cec9-bf47-edaa-c775c2f544fb@nvidia.com>
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On Mon, 2019-09-23 at 12:58 -0700, John Hubbard wrote:
>
> CPU 0 CPU 1
> ------ --------------
> READ(pte) (re-ordered at run time)
> atomic_inc(val) (no run-time memory barrier!)
>
> pmd_clear(pte)
> if (val)
> run_on_all_cpus(): IPI
> local_irq_disable() (also not a mem barrier)
>
> if(pte)
> walk page tables
Let me see if I can understand,
On most patches, it would be:
CPU 0 CPU 1
------ --------------
ptep = __find_linux_pte
(re-ordered at run time)
atomic_inc(val)
pmd_clear(pte)
smp_mb()
if (val)
run_on_all_cpus(): IPI
local_irq_disable()
if(ptep)
pte = *ptep;
Is that what you meant?
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next prev parent reply other threads:[~2019-09-23 20:25 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-20 19:50 [PATCH v2 00/11] Introduces new count-based method for monitoring lockless pagetable wakls Leonardo Bras
2019-09-20 19:50 ` [PATCH v2 01/11] powerpc/mm: Adds counting method to monitor lockless pgtable walks Leonardo Bras
2019-09-23 20:42 ` John Hubbard
2019-09-23 20:50 ` Leonardo Bras
2019-09-20 19:50 ` [PATCH v2 02/11] asm-generic/pgtable: Adds dummy functions " Leonardo Bras
2019-09-23 20:39 ` John Hubbard
2019-09-23 20:48 ` Leonardo Bras
2019-09-23 20:53 ` John Hubbard
2019-09-20 19:50 ` [PATCH v2 03/11] mm/gup: Applies counting method to monitor gup_pgd_range Leonardo Bras
2019-09-23 20:27 ` John Hubbard
2019-09-23 21:01 ` Leonardo Bras
2019-09-23 21:09 ` John Hubbard
2019-09-20 19:50 ` [PATCH v2 04/11] powerpc/mce_power: Applies counting method to monitor lockless pgtbl walks Leonardo Bras
2019-09-20 19:50 ` [PATCH v2 05/11] powerpc/perf: " Leonardo Bras
2019-09-20 19:50 ` [PATCH v2 06/11] powerpc/mm/book3s64/hash: " Leonardo Bras
2019-09-20 19:50 ` [PATCH v2 07/11] powerpc/kvm/e500: " Leonardo Bras
2019-09-20 19:50 ` [PATCH v2 08/11] powerpc/kvm/book3s_hv: " Leonardo Bras
2019-09-23 20:47 ` John Hubbard
2019-09-20 19:50 ` [PATCH v2 09/11] powerpc/kvm/book3s_64: " Leonardo Bras
2019-09-20 19:50 ` [PATCH v2 10/11] powerpc/book3s_64: Enables counting method to monitor lockless pgtbl walk Leonardo Bras
2019-09-20 19:50 ` [PATCH v2 11/11] powerpc/mm/book3s64/pgtable: Uses counting method to skip serializing Leonardo Bras
2019-09-20 20:11 ` John Hubbard
2019-09-20 20:28 ` Leonardo Bras
2019-09-20 21:15 ` John Hubbard
2019-09-21 0:48 ` John Hubbard
2019-09-23 17:25 ` Leonardo Bras
2019-09-23 18:14 ` John Hubbard
2019-09-23 19:40 ` Leonardo Bras
2019-09-23 19:58 ` John Hubbard
2019-09-23 20:23 ` Leonardo Bras [this message]
2019-09-23 20:26 ` John Hubbard
2019-09-20 19:56 ` [PATCH v2 00/11] Introduces new count-based method for monitoring lockless pagetable wakls Leonardo Bras
2019-09-20 20:12 ` Leonardo Bras
2019-09-20 21:24 ` John Hubbard
2019-09-23 20:51 ` John Hubbard
2019-09-23 20:58 ` Leonardo Bras
2019-09-24 21:23 [PATCH v2 11/11] powerpc/mm/book3s64/pgtable: Uses counting method to skip serializing Leonardo Bras
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