From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E6815C4332F for ; Fri, 22 Oct 2021 09:03:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CEE3361205 for ; Fri, 22 Oct 2021 09:03:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232531AbhJVJFl (ORCPT ); Fri, 22 Oct 2021 05:05:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:37204 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232547AbhJVJFk (ORCPT ); Fri, 22 Oct 2021 05:05:40 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id B2E5E611CB; Fri, 22 Oct 2021 09:03:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1634893403; bh=o2rX01+ZUM8v0v0greyBGNE1DypzwZSAOJDUMHdaR9I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PikmEw5O9n/9NAmxCZiLlNkGV6RCd4XSU1m/fL5uWP7HQNhd2kw0+t+2tdSITSLGY 2xROdyWrASKgeHi94rnKJLMBnHKQmHbid1Pz8mtnBAXMswVK++0zHPqICAOlHNoiEL LCLTIpApVY6DNiU44nX6mAGQuCiyDc719shhRWV48DhkzbtodUKxOMmEPQHH9trWEO m/A/zjxF00gEWyL45NEGKtwvbycxEVAmHsLKUSgTHhdf1fiCGY7Xc6LNFx4pXOKrSG KKclpoWD1OZrhT70Q1gmc+Nc6qc5z0KrKDSMYqgYfmtI3z9RTafGSDaFf8kketmBO2 RgXd0YO4zCe8w== From: SeongJae Park To: akpm@linux-foundation.org, corbet@lwn.net Cc: peterx@redhat.com, linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, SeongJae Park Subject: [PATCH 4/4] Docs/admin-guide/mm/pagemap: Wordsmith page flags descriptions Date: Fri, 22 Oct 2021 09:03:11 +0000 Message-Id: <20211022090311.3856-5-sj@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20211022090311.3856-1-sj@kernel.org> References: <20211022090311.3856-1-sj@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org Some descriptions of page flags in 'pagemap.rst' are written in assumption of none-rst, which respects every new line, as below: 7 - SLAB page is managed by the SLAB/SLOB/SLUB/SLQB kernel memory allocator When compound page is used, SLUB/SLQB will only set this flag on the head Because rst ignores the new line between the first sentence and second sentence, resulting html looks a little bit weird, as below. 7 - SLAB page is managed by the SLAB/SLOB/SLUB/SLQB kernel memory allocator When ^ compound page is used, SLUB/SLQB will only set this flag on the head page; SLOB will not flag it at all. This commit makes it more natural and consistent with other parts in the rendered version. Signed-off-by: SeongJae Park --- Documentation/admin-guide/mm/pagemap.rst | 53 ++++++++++++------------ 1 file changed, 27 insertions(+), 26 deletions(-) diff --git a/Documentation/admin-guide/mm/pagemap.rst b/Documentation/admin-guide/mm/pagemap.rst index fdc19fbc1083..242d84315066 100644 --- a/Documentation/admin-guide/mm/pagemap.rst +++ b/Documentation/admin-guide/mm/pagemap.rst @@ -90,13 +90,14 @@ Short descriptions to the page flags ==================================== 0 - LOCKED - page is being locked for exclusive access, e.g. by undergoing read/write IO + The page is being locked for exclusive access, e.g. by undergoing read/write + IO. 7 - SLAB - page is managed by the SLAB/SLOB/SLUB/SLQB kernel memory allocator + The page is managed by the SLAB/SLOB/SLUB/SLQB kernel memory allocator. When compound page is used, SLUB/SLQB will only set this flag on the head page; SLOB will not flag it at all. 10 - BUDDY - a free memory block managed by the buddy system allocator + A free memory block managed by the buddy system allocator. The buddy system organizes free memory in blocks of various orders. An order N block has 2^N physically contiguous pages, with the BUDDY flag set for and _only_ for the first page. @@ -112,65 +113,65 @@ Short descriptions to the page flags 16 - COMPOUND_TAIL A compound page tail (see description above). 17 - HUGE - this is an integral part of a HugeTLB page + This is an integral part of a HugeTLB page. 19 - HWPOISON - hardware detected memory corruption on this page: don't touch the data! + Hardware detected memory corruption on this page: don't touch the data! 20 - NOPAGE - no page frame exists at the requested address + No page frame exists at the requested address. 21 - KSM - identical memory pages dynamically shared between one or more processes + Identical memory pages dynamically shared between one or more processes. 22 - THP - contiguous pages which construct transparent hugepages + Contiguous pages which construct transparent hugepages. 23 - OFFLINE - page is logically offline + The page is logically offline. 24 - ZERO_PAGE - zero page for pfn_zero or huge_zero page + Zero page for pfn_zero or huge_zero page. 25 - IDLE - page has not been accessed since it was marked idle (see + The page has not been accessed since it was marked idle (see :ref:`Documentation/admin-guide/mm/idle_page_tracking.rst `). Note that this flag may be stale in case the page was accessed via a PTE. To make sure the flag is up-to-date one has to read ``/sys/kernel/mm/page_idle/bitmap`` first. 26 - PGTABLE - page is in use as a page table + The page is in use as a page table. IO related page flags --------------------- 1 - ERROR - IO error occurred + IO error occurred. 3 - UPTODATE - page has up-to-date data + The page has up-to-date data. ie. for file backed page: (in-memory data revision >= on-disk one) 4 - DIRTY - page has been written to, hence contains new data + The page has been written to, hence contains new data. i.e. for file backed page: (in-memory data revision > on-disk one) 8 - WRITEBACK - page is being synced to disk + The page is being synced to disk. LRU related page flags ---------------------- 5 - LRU - page is in one of the LRU lists + The page is in one of the LRU lists. 6 - ACTIVE - page is in the active LRU list + The page is in the active LRU list. 18 - UNEVICTABLE - page is in the unevictable (non-)LRU list It is somehow pinned and + The page is in the unevictable (non-)LRU list It is somehow pinned and not a candidate for LRU page reclaims, e.g. ramfs pages, - shmctl(SHM_LOCK) and mlock() memory segments + shmctl(SHM_LOCK) and mlock() memory segments. 2 - REFERENCED - page has been referenced since last LRU list enqueue/requeue + The page has been referenced since last LRU list enqueue/requeue. 9 - RECLAIM - page will be reclaimed soon after its pageout IO completed + The page will be reclaimed soon after its pageout IO completed. 11 - MMAP - a memory mapped page + A memory mapped page. 12 - ANON - a memory mapped page that is not part of a file + A memory mapped page that is not part of a file. 13 - SWAPCACHE - page is mapped to swap space, i.e. has an associated swap entry + The page is mapped to swap space, i.e. has an associated swap entry. 14 - SWAPBACKED - page is backed by swap/RAM + The page is backed by swap/RAM. The page-types tool in the tools/vm directory can be used to query the above flags. -- 2.17.1