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[198.145.29.99]) by mx.google.com with ESMTPS id x24si488500pgh.393.2019.06.13.12.29.57 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 13 Jun 2019 12:29:58 -0700 (PDT) Received-SPF: pass (google.com: domain of akpm@linux-foundation.org designates 198.145.29.99 as permitted sender) client-ip=198.145.29.99; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=PsKvLzul; spf=pass (google.com: domain of akpm@linux-foundation.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org Received: from akpm3.svl.corp.google.com (unknown [104.133.8.65]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 55DF62147A; Thu, 13 Jun 2019 19:29:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560454197; bh=3nq7RwSer/Bwj8wjlB+pF0Ss6fAkxhqxBxJF0LKmZok=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=PsKvLzul3M76GkVQT+iREuWkduH+sv/EbpqVqvWMxorQopPHVDOT2k5gkJNIiKZLo Wt8JuIjy7KWL7G7WfDWj49p2z5kDCYd6eCd4e/tJkh8JYO8BuqeKnzN4SCFIjyzuSX 8pGOSssDk1JR7zA93vfBURmASTgo8/sfqPOhARXQ= Date: Thu, 13 Jun 2019 12:29:56 -0700 From: Andrew Morton To: Joel Savitz Cc: linux-kernel@vger.kernel.org, Alexey Dobriyan , Vlastimil Babka , "Aneesh Kumar K.V" , Michael Ellerman , Ram Pai , Andrea Arcangeli , Huang Ying , Sandeep Patil , Rafael Aquini , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH v4] fs/proc: add VmTaskSize field to /proc/$$/status Message-Id: <20190613122956.2fe1e200419c6497159044a0@linux-foundation.org> In-Reply-To: <1560437690-13919-1-git-send-email-jsavitz@redhat.com> References: <1560437690-13919-1-git-send-email-jsavitz@redhat.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, 13 Jun 2019 10:54:50 -0400 Joel Savitz wrote: > The kernel provides no architecture-independent mechanism to get the > size of the virtual address space of a task (userspace process) without > brute-force calculation. This patch allows a user to easily retrieve > this value via a new VmTaskSize entry in /proc/$$/status. Why is access to ->task_size required? Please fully describe the use case. > --- a/Documentation/filesystems/proc.txt > +++ b/Documentation/filesystems/proc.txt > @@ -187,6 +187,7 @@ read the file /proc/PID/status: > VmLib: 1412 kB > VmPTE: 20 kb > VmSwap: 0 kB > + VmTaskSize: 137438953468 kB > HugetlbPages: 0 kB > CoreDumping: 0 > THP_enabled: 1 > @@ -263,6 +264,7 @@ Table 1-2: Contents of the status files (as of 4.19) > VmPTE size of page table entries > VmSwap amount of swap used by anonymous private data > (shmem swap usage is not included) > + VmTaskSize size of task (userspace process) vm space This is rather vague. Is it the total amount of physical memory? The sum of all vma sizes, populated or otherwise? Something else?