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From: Balbir Singh <bsingharora@gmail.com>
To: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
	benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au,
	akpm@linux-foundation.org,
	Mel Gorman <mgorman@techsingularity.net>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH V3] powerpc/mm: Fix Multi hit ERAT cause by recent THP update
Date: Mon, 15 Feb 2016 16:09:57 +1100	[thread overview]
Message-ID: <1455512997.16012.24.camel@gmail.com> (raw)
In-Reply-To: <87lh6mfv2j.fsf@linux.vnet.ibm.com>


> Now we can't depend for mm_cpumask, a parallel find_linux_pte_hugepte
> can happen outside that. Now i had a variant for kick_all_cpus_sync that
> ignored idle cpus. But then that needs more verification.
> 
> http://article.gmane.org/gmane.linux.ports.ppc.embedded/81105
Can be racy as a CPU moves from non-idle to idle

In

> +A A A A A pmd_hugepage_update(vma->vm_mm, address, pmdp, ~0UL, 0);
> +A A A A A /*
> +A A A A A A * This ensures that generic code that rely on IRQ disabling
> +A A A A A A * to prevent a parallel THP split work as expected.
> +A A A A A A */
> +A A A A A kick_all_cpus_sync();

pmdp_invalidate()->pmd_hugepage_update() can still run in parallel withA 
find_linux_pte_or_hugepte() and race.. Am I missing something?

Balbir Singh


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  reply	other threads:[~2016-02-15  5:10 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-09  1:20 [PATCH V3] powerpc/mm: Fix Multi hit ERAT cause by recent THP update Aneesh Kumar K.V
2016-02-09 12:16 ` [V3] " Michael Ellerman
2016-02-14  5:32   ` Aneesh Kumar K.V
2016-02-15  2:44 ` [PATCH V3] " Balbir Singh
2016-02-15  4:37   ` Aneesh Kumar K.V
2016-02-15  5:09     ` Balbir Singh [this message]
2016-02-15 11:01       ` Aneesh Kumar K.V
2016-02-16  5:20         ` Balbir Singh

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