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Fri, 4 Apr 2025 12:02:09 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=pankajraghav.com; s=MBO0001; t=1743760929; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=r1n2IxWlUE89EoDyUJBLsMZNprUF531kxdOHKEj7v28=; b=slo0eJoLEEk/AJi3BQQ0cMlesfWdKZO/53yPXbi4i+Wct5sKcHpwiGdxEbx0Kh9mn3aMsR HyhXrg7ZvYO4cg3KJ92KTCqQSbV3z/hqBGE2/RGGl1UZoNwt5JMyTNDkmJwxPMiO2XWaDR G+pcXDAzD/ZbPhtHCMI2Yjg3/CfVlpVyMlDmShr69OnLcXB0aI3BtlDmVlAvKUkb1H2//f xxkif4/lENVztAdS3sA3uG6gxqoV6nFN7TyYCdfHNsKOltSJ5Ip5T4fgSXa1WSBqEwYdQY Ne0O6V5VJH2NMeLUYF62gyJjr5DIaDFQrT3Y++qyVDvDZJmI3j5JMpcmKQ2N5w== From: "Pankaj Raghav (Samsung)" To: Andrew Morton , Jonathan Corbet Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, willy@infradead.org, David Hildenbrand , Bagas Sanjaya , da.gomez@kernel.org, mcgrof@kernel.org, gost.dev@samsung.com, linux-doc@vger.kernel.org, kernel@pankajraghav.com, Pankaj Raghav Subject: [PATCH v2 2/2] docs: clarify THP admin guide about (File|Shmem)PmdMapped and ShmemHugePage Date: Fri, 4 Apr 2025 12:01:59 +0200 Message-ID: <20250404100159.27086-3-kernel@pankajraghav.com> In-Reply-To: <20250404100159.27086-1-kernel@pankajraghav.com> References: <20250404100159.27086-1-kernel@pankajraghav.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 33F80120011 X-Stat-Signature: qit444k8jcpwusbmaxp5ez6aefe7hh1b X-HE-Tag: 1743760932-891183 X-HE-Meta: U2FsdGVkX1/nHnDU/CJmlGw8opDRG6XFjRyH9NJQ5QE768nAL/sP14XDGJGw3mhNWB4HCnQa43FuxCsKnUJNDqW393IezTqMYNGjj/1O7/N5aceQQqo9vbWzqaLcemhnlQfHbmwU3qNJVHeYrOiYFIlAUr4SjIuCuvG/Bz9naZQKofVMUYXp1HkXt8NS4TIdYIld+eRr/hIgdzMoBqCWrXnJwBgzR5mqNWb+KRGRBtRnq4yoFKby7cXJD1qcBBplnGz1WQUYVvmJ9o0VDFmAiwXSnSOCdmRqIH5QNnvkKOvoDIG4AwWBGbqWe2Xaja1Rm7Bj6DzrAV9MTHgApZ0k+XzsfM0X640nndHT32k0acq1l3Y45Asunspv7Hryp0pfV8km2TLSYOptWPIJ+uKTEuyBvXZQstoIkwCqfjCH2rqtTO307Ofi6TooH8pAtWQiplG2r/k2URZgbvJ6ZCgELXSEJ05iiXD731tE9D1rARxoyo1tCxTLzoizey/wF+HroUVchAWk6hXDy3n/pm4zAGKAgQo7RBs6TbuahlBJrug/4Zn3UQLvoE7wqoX03vJnHu94inTutgNXZ9UE9fP7kkqjwdImEX2I8PcdBruAdlRap3KyHj3nfTU7brUwTfB4K2xTQwyidFrNsfcjdSk/uC8aIMiFnP16Bo4XtM7zT4s7Qid0jBMxi0HjpLyM4WUnz33Lq9Afpg3ftj9CkMgLiF7Xfw0YzvhhftBr2v4dzmXxDlfhod4VxjfIAC9f4CDldVB3MXsdK63Zgqp2232fXShGcHmE5GdLkQCOuK02zH1zQEDguJTM2GQG87ccannOt8frZ84wuHDl4kFf4Oa+7H24eQOHwBgbFXWyNbHcah8ybFhvMyj0WY6BnTQZF2Mrq0gBqelC+ZIvvNsm4JUkqjlCbRCvTfe4s7GUPKpMPN2F9lK+lXZnDp658FbbkYbZcLYhIsGi6nxq//eErpc lTwC0X5g qRbrPfsVSfyFRiWCIvWDhTlDeBVHyf1y/698kz+glD2uivZztCdvg84Ljmxr9TS+pkcdCMQWrMPJ5vJMWoDHhNUtSwEn8FhmP8947euCSWH5iOOMVI8eljoWV98uQoqFbsOMoOsuWQ5nCA4J5xzQmeRZsQdpvzemrDAMzzUi9a+H1//tzv7yxdDBorYV9/Og4Cu6zXUsq+JZIBdbxY7tyoFrorUBPjP4C/UxjFhD0LshoaiXYQ1cE/jUs9OP9NdaOLi0/4n9Zsi8mTTY= 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: List-Subscribe: List-Unsubscribe: From: Pankaj Raghav Move FilePmdMapped to previous paragraph for clarity, and clarify ShmemPmdMapped & ShmemHugePage. Signed-off-by: Pankaj Raghav --- Documentation/admin-guide/mm/transhuge.rst | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/Documentation/admin-guide/mm/transhuge.rst b/Documentation/admin-guide/mm/transhuge.rst index 01b7ce90d693..b0b9d578732b 100644 --- a/Documentation/admin-guide/mm/transhuge.rst +++ b/Documentation/admin-guide/mm/transhuge.rst @@ -465,13 +465,17 @@ AnonHugePmdMapped). The number of PMD-sized transparent huge pages currently used by filesystem data (page cache) is available by reading the FileHugePages field -in ``/proc/meminfo``. +in ``/proc/meminfo``. The number of these huge pages that are mapped to userspace +is available by reading FilePmdMapped field in ``proc/meminfo``. To identify +what applications are mapping these huge pages, it is necessary to read +``/proc/PID/smaps`` and count the FilePmdMapped fields for each mapping. -The number of file transparent huge pages mapped to userspace is available -by reading ShmemPmdMapped and ShmemHugePages fields in ``/proc/meminfo``. -To identify what applications are mapping file transparent huge pages, it -is necessary to read ``/proc/PID/smaps`` and count the FilePmdMapped fields -for each mapping. +The number of PMD-sized transparent huge pages currently used by +tmpfs/shmem is available by reading the ShmemHugePages field +in ``/proc/meminfo``. The number of these huge pages that are mapped to userspace +is available by reading ShmemPmdMapped field in ``proc/meminfo``. To identify +what applications are mapping these huge pages, it is necessary to read +``/proc/PID/smaps`` and count the ShmemPmdMapped fields for each mapping. Note that reading the smaps file is expensive and reading it frequently will incur overhead. -- 2.47.2