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Shutemov" , Peter Xu , Suren Baghdasaryan , Arnd Bergmann , Tong Tiangen , Pasha Tatashin , Li kunyu , Nadav Amit , Anshuman Khandual , Minchan Kim , Yang Shi , Song Liu , Miaohe Lin , Thomas Gleixner , Sebastian Andrzej Siewior , Andy Lutomirski , Fenghua Yu , Dinglan Peng , Pedro Fonseca , Jim Huang , Huichun Feng , Chih-En Lin Subject: [RFC PATCH v2 3/9] mm, pgtable: Add ownership to PTE table Date: Wed, 28 Sep 2022 00:29:51 +0800 Message-Id: <20220927162957.270460-4-shiyn.lin@gmail.com> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20220927162957.270460-1-shiyn.lin@gmail.com> References: <20220927162957.270460-1-shiyn.lin@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1664296073; a=rsa-sha256; cv=none; b=JmL7+DYkfGmb7v+M3HIJEc9bJ8NG/8UkW6Z5qskqjhd8MgiH0S8ibbdUupv0frBdA8phd+ F0KtBiX4P+uEAtjziN2YMruUhmQQ5fCJatUuQ+SeSwgnOfLFoi9itQZ+YqAHDoRJ3LVbQA KloryLO7cGjwjMsx9QBzxHmna/ET1TY= ARC-Authentication-Results: i=1; imf08.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=bdViRXIQ; spf=pass (imf08.hostedemail.com: domain of shiyn.lin@gmail.com designates 209.85.215.177 as permitted sender) smtp.mailfrom=shiyn.lin@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1664296073; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=qop4kS7tfgVAWONSShTjlSwOzcS5SD4NChZjNU/F2nQ=; b=djJ/z3CXui5veo5asOUuXNraB5rYHT7bmSkVjpCiTuxiLO2cVoNLrjBy0529a5/aIG1/lP WqX41j7XVCHVprxkpW/iVBD2fL1oqasOHBZKFBzEJsvV1P2U2hrEIUBV+71jw77+fcynZ2 WkgF6j97xIynJgVq6YBhCv/NxcpVsQk= X-Rspamd-Server: rspam10 X-Rspam-User: Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=bdViRXIQ; spf=pass (imf08.hostedemail.com: domain of shiyn.lin@gmail.com designates 209.85.215.177 as permitted sender) smtp.mailfrom=shiyn.lin@gmail.com; dmarc=pass (policy=none) header.from=gmail.com X-Stat-Signature: xnzxfodcygr759oka56jb1w1ankxjjrs X-Rspamd-Queue-Id: 7761216001C X-HE-Tag: 1664296073-683586 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: Introduce the ownership to the PTE table. It uses the address of PMD index to track the ownership to identify which process can update their page table state from the COWed PTE table. Signed-off-by: Chih-En Lin --- include/linux/mm.h | 1 + include/linux/mm_types.h | 5 ++++- include/linux/pgtable.h | 10 ++++++++++ 3 files changed, 15 insertions(+), 1 deletion(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 21f8b27bd9fd3..965523dcca3b8 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2289,6 +2289,7 @@ static inline bool pgtable_pte_page_ctor(struct page *page) return false; __SetPageTable(page); inc_lruvec_page_state(page, NR_PAGETABLE); + page->cow_pte_owner = NULL; return true; } diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index cf97f3884fda2..42798b59cec4e 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -152,7 +152,10 @@ struct page { struct list_head deferred_list; }; struct { /* Page table pages */ - unsigned long _pt_pad_1; /* compound_head */ + union { + unsigned long _pt_pad_1; /* compound_head */ + pmd_t *cow_pte_owner; /* cow pte: pmd */ + }; pgtable_t pmd_huge_pte; /* protected by page->ptl */ unsigned long _pt_pad_2; /* mapping */ union { diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h index d03d01aefe989..9dca787a3f4dd 100644 --- a/include/linux/pgtable.h +++ b/include/linux/pgtable.h @@ -615,6 +615,16 @@ static inline int pte_unused(pte_t pte) } #endif +static inline void set_cow_pte_owner(pmd_t *pmd, pmd_t *owner) +{ + smp_store_release(&pmd_page(*pmd)->cow_pte_owner, owner); +} + +static inline bool cow_pte_owner_is_same(pmd_t *pmd, pmd_t *owner) +{ + return smp_load_acquire(&pmd_page(*pmd)->cow_pte_owner) == owner; +} + #ifndef pte_access_permitted #define pte_access_permitted(pte, write) \ (pte_present(pte) && (!(write) || pte_write(pte))) -- 2.37.3