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From: Anshuman Khandual <khandual@linux.vnet.ibm.com>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	linux-api@vger.kernel.org, Michal Hocko <mhocko@kernel.org>
Subject: Re: [PATCH 2/2] mm: Consolidate page table accounting
Date: Thu, 5 Oct 2017 10:38:29 +0530	[thread overview]
Message-ID: <3aabab03-7f0a-e82e-a1c2-79120aed5ace@linux.vnet.ibm.com> (raw)
In-Reply-To: <20171004163648.11234-2-kirill.shutemov@linux.intel.com>

On 10/04/2017 10:06 PM, Kirill A. Shutemov wrote:
> This patch switches page table accounting to single counter from
> three -- nr_ptes, nr_pmds and nr_puds.
> 
> mm->pgtables_bytes is now used to account page table levels. We use
> bytes, because page table size for different levels of page table tree
> may be different.
> 
> The change has user-visible effect: we don't have VmPMD and VmPUD
> reported in /proc/[pid]/status. Not sure if anybody uses them.
> (As alternative, we can always report 0 kB for them.)
> 
> OOM-killer report is also slightly changed: we now report pgtables_bytes
> instead of nr_ptes, nr_pmd, nr_puds.

Could you please mention the motivation of doing this ? Why we are
consolidating the counters which also changes /proc/ interface as
well as OOM report ? What is the benefit ?

WARNING: multiple messages have this Message-ID (diff)
From: Anshuman Khandual <khandual-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
To: "Kirill A. Shutemov"
	<kirill.shutemov-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>,
	Andrew Morton
	<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Cc: linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Michal Hocko <mhocko-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Subject: Re: [PATCH 2/2] mm: Consolidate page table accounting
Date: Thu, 5 Oct 2017 10:38:29 +0530	[thread overview]
Message-ID: <3aabab03-7f0a-e82e-a1c2-79120aed5ace@linux.vnet.ibm.com> (raw)
In-Reply-To: <20171004163648.11234-2-kirill.shutemov-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>

On 10/04/2017 10:06 PM, Kirill A. Shutemov wrote:
> This patch switches page table accounting to single counter from
> three -- nr_ptes, nr_pmds and nr_puds.
> 
> mm->pgtables_bytes is now used to account page table levels. We use
> bytes, because page table size for different levels of page table tree
> may be different.
> 
> The change has user-visible effect: we don't have VmPMD and VmPUD
> reported in /proc/[pid]/status. Not sure if anybody uses them.
> (As alternative, we can always report 0 kB for them.)
> 
> OOM-killer report is also slightly changed: we now report pgtables_bytes
> instead of nr_ptes, nr_pmd, nr_puds.

Could you please mention the motivation of doing this ? Why we are
consolidating the counters which also changes /proc/ interface as
well as OOM report ? What is the benefit ?

WARNING: multiple messages have this Message-ID (diff)
From: Anshuman Khandual <khandual@linux.vnet.ibm.com>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	linux-api@vger.kernel.org, Michal Hocko <mhocko@kernel.org>
Subject: Re: [PATCH 2/2] mm: Consolidate page table accounting
Date: Thu, 5 Oct 2017 10:38:29 +0530	[thread overview]
Message-ID: <3aabab03-7f0a-e82e-a1c2-79120aed5ace@linux.vnet.ibm.com> (raw)
In-Reply-To: <20171004163648.11234-2-kirill.shutemov@linux.intel.com>

On 10/04/2017 10:06 PM, Kirill A. Shutemov wrote:
> This patch switches page table accounting to single counter from
> three -- nr_ptes, nr_pmds and nr_puds.
> 
> mm->pgtables_bytes is now used to account page table levels. We use
> bytes, because page table size for different levels of page table tree
> may be different.
> 
> The change has user-visible effect: we don't have VmPMD and VmPUD
> reported in /proc/[pid]/status. Not sure if anybody uses them.
> (As alternative, we can always report 0 kB for them.)
> 
> OOM-killer report is also slightly changed: we now report pgtables_bytes
> instead of nr_ptes, nr_pmd, nr_puds.

Could you please mention the motivation of doing this ? Why we are
consolidating the counters which also changes /proc/ interface as
well as OOM report ? What is the benefit ?

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  reply	other threads:[~2017-10-05  5:08 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-04 16:36 [PATCH 1/2] mm: Introduce wrapper to access mm->nr_ptes Kirill A. Shutemov
2017-10-04 16:36 ` Kirill A. Shutemov
2017-10-04 16:36 ` Kirill A. Shutemov
2017-10-04 16:36 ` [PATCH 2/2] mm: Consolidate page table accounting Kirill A. Shutemov
2017-10-04 16:36   ` Kirill A. Shutemov
2017-10-05  5:08   ` Anshuman Khandual [this message]
2017-10-05  5:08     ` Anshuman Khandual
2017-10-05  5:08     ` Anshuman Khandual
2017-10-05 10:10     ` Kirill A. Shutemov
2017-10-05 10:10       ` Kirill A. Shutemov
2017-10-04 18:35 ` [PATCH 1/2] mm: Introduce wrapper to access mm->nr_ptes Mike Kravetz
2017-10-04 18:35   ` Mike Kravetz
2017-10-04 18:35   ` Mike Kravetz
2017-10-05 10:10   ` Kirill A. Shutemov
2017-10-05 10:10     ` Kirill A. Shutemov

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