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c=relaxed/relaxed; d=pankajraghav.com; s=MBO0001; t=1743760926; 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=gVpYu65d0kR5ehI3vJ4JKoscmExvd9Tzl/16BBwPR5I=; b=akGA+gGjrYpUfm74/YuZ+Su4tLoG/4vg34vI2tSE2z+6QsUpoKUQLztalYhSXm8SlbG1r8 kjtMKiVbKb7E6gIEQi1kU4GcjNTwGiuxzb1CVmYj43uyhcrIdObN5aLJdx04BCiLhy5Qmy 704yr1itTv9cgSJNyM5B53t7AKysO+f9tFyYHf05An0EF4AZsBD3wZwlEOxJM+FfmAz7GP PqP+mEOBr52yI/4C9aH2W9CY0p5eNyCIQctD0AowPYgATx99s/FTDEwfP3bHE946SvhX1K CXHxw/VpNXgiudhVQTIRd3yT54NjOT1YLfrZgKDvKDX79OMkf0Xg5XPq7zIzPQ== 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 1/2] docs: update THP admin guide about non-tmpfs filesystem support Date: Fri, 4 Apr 2025 12:01:58 +0200 Message-ID: <20250404100159.27086-2-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-Stat-Signature: d17okat444eqkezfrmt5h3rw6z19jjuh X-Rspam-User: X-Rspamd-Queue-Id: 4FB93A001D X-Rspamd-Server: rspam08 X-HE-Tag: 1743760930-67803 X-HE-Meta: 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 NCeBDGEt CoyRcrMasQV4S9nxb0/JgR4jpHpIYc+TfoUEYqtZ6C0akwPKxpC35ro1DRdhZRKHJAe9vMcvVrvrcWFtd9GH9ml/x3VWJ1w6MYC6zoqUFnqjSKSZgUKdEKKkkBfwabnkp3zUWfKETZ6/quoYHSmfcnvKK+NRcmQVsxosi7BSf1k6IwNXKgvumLOPX+Umh6qYLxjQuL5JyGWYZgvUtrqRP70alNQo5RsebzOWj16yc6QWC43+D4R5gUSRU1dWfzqJI/Du8Vd78hXqp3A7f1ddVmQnoBPF+O8X8mca1jNWSnTie4wE2F2S7voBxTQ== 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 THP support for non-tmpfs filesystem has been around for some time now. Update the admin guide to reflect it. Signed-off-by: Pankaj Raghav Reviewed-by: Bagas Sanjaya --- Documentation/admin-guide/mm/transhuge.rst | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/Documentation/admin-guide/mm/transhuge.rst b/Documentation/admin-guide/mm/transhuge.rst index dff8d5985f0f..01b7ce90d693 100644 --- a/Documentation/admin-guide/mm/transhuge.rst +++ b/Documentation/admin-guide/mm/transhuge.rst @@ -12,8 +12,8 @@ using huge pages for the backing of virtual memory with huge pages that supports the automatic promotion and demotion of page sizes and without the shortcomings of hugetlbfs. -Currently THP only works for anonymous memory mappings and tmpfs/shmem. -But in the future it can expand to other filesystems. +Currently, THP only works for anonymous memory mappings, tmpfs/shmem and +filesystems that support large folios. .. note:: in the examples below we presume that the basic page size is 4K and @@ -463,6 +463,10 @@ fields for each mapping. (Note that AnonHugePages only applies to traditional PMD-sized THP for historical reasons and should have been called 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``. + 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 -- 2.47.2