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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1F041C433F5 for ; Fri, 29 Apr 2022 13:37:51 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B7C966B007B; Fri, 29 Apr 2022 09:37:50 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B05E06B007D; Fri, 29 Apr 2022 09:37:50 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9588C6B0082; Fri, 29 Apr 2022 09:37:50 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.27]) by kanga.kvack.org (Postfix) with ESMTP id 83F8F6B007B for ; Fri, 29 Apr 2022 09:37:50 -0400 (EDT) Received: from smtpin26.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay13.hostedemail.com (Postfix) with ESMTP id 5CB8D6050F for ; Fri, 29 Apr 2022 13:37:50 +0000 (UTC) X-FDA: 79410019500.26.71B88D7 Received: from mail-pj1-f48.google.com (mail-pj1-f48.google.com [209.85.216.48]) by imf14.hostedemail.com (Postfix) with ESMTP id BE5D610002F for ; Fri, 29 Apr 2022 13:37:48 +0000 (UTC) Received: by mail-pj1-f48.google.com with SMTP id z5-20020a17090a468500b001d2bc2743c4so7324987pjf.0 for ; Fri, 29 Apr 2022 06:37:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20210112.gappssmtp.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=VvydQG5zjUSumdtIipaqFpls71i8yJoag+sGGmgO3rc=; b=7NbcGgSkwHrJY1tx3toqeV+Xk5yX2uYskO+z5MFj6UbbTYBe0q1WO97WvSjnChdIC7 i1KaBtCoZvUzFuHqvg/yX7Sermx9dZh9Iowvqovf+yqAqOU9nR2rvNz8vX4p8YMW9Pr/ lcrLnleXLlHf98P6UtW9P6LVIs3t/qYmRfgfSYvLdrou9KwvgQiL7q66BHZj/JDMNoUC D900OhH7LCn0E2x6kfYvQ9+i0goWdK5HbTs5N9gnfI5iJNzW/g4nC1cnBFMZbnmGJu/U 3ZC4/cu0R2dvf0oaLfZZa5zTEhGLX+Dy1LhFT0O/TkQEjvp4dUTJFE4jWAq0xK4ZGERA XgYw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=VvydQG5zjUSumdtIipaqFpls71i8yJoag+sGGmgO3rc=; b=DjwIEDCYMZxxEPUMcyPdXyaMAWY9F/RBwTASd4UXEq1gU100GVEYe/oiYLTCIRTCeV wp+eIYEyxmUMWnl75iGltosLv6eYd39quBFjsGW1NNrBmNI9QlOPbaF8w+JLyQqLjxkB b2TyZyZUojvu76nunWhh6GvSH8xwsoT/Wz9iF5aWB2Me25WMezN///tiL7GXfaF5xg2G 527CsBx1nF6mBiZkDC0s3oa9mcmT3p/PD4APRsOM/LmStKN5S+eGs7MVPPZkAxfq0fcP azmrACRbGE2D0ZpZcCNxKpqjXBp4Z+B6vIHeBnA2JXICpSKxBR8Q7bvhcGk2htY1kq9j 2UwA== X-Gm-Message-State: AOAM533hi+qj4NRAyJTkB9wpe7uDU6cg6dtNK2Bh6okgX9TNmwbl0Jxh pRPd8qx79JF2o7bE8Cj/DebEKS7Gjoopag== X-Google-Smtp-Source: ABdhPJzNnW/PfivTTKMAdGz8oCU9UxMQX9vEZMqhPr9ijXGFPd76Q1h9afEdGPE6Q5AkyqAGhbs2Cw== X-Received: by 2002:a17:90a:784b:b0:1db:dfe6:5d54 with SMTP id y11-20020a17090a784b00b001dbdfe65d54mr3938283pjl.112.1651239468914; Fri, 29 Apr 2022 06:37:48 -0700 (PDT) Received: from localhost.localdomain ([139.177.225.240]) by smtp.gmail.com with ESMTPSA id m8-20020a17090a414800b001d81a30c437sm10681977pjg.50.2022.04.29.06.37.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 29 Apr 2022 06:37:48 -0700 (PDT) From: Qi Zheng To: akpm@linux-foundation.org, tglx@linutronix.de, kirill.shutemov@linux.intel.com, mika.penttila@nextfour.com, david@redhat.com, jgg@nvidia.com, tj@kernel.org, dennis@kernel.org, ming.lei@redhat.com Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, songmuchun@bytedance.com, zhouchengming@bytedance.com, Qi Zheng Subject: [RFC PATCH 16/18] pte_ref: add track_pte_{set, clear}() helper Date: Fri, 29 Apr 2022 21:35:50 +0800 Message-Id: <20220429133552.33768-17-zhengqi.arch@bytedance.com> X-Mailer: git-send-email 2.24.3 (Apple Git-128) In-Reply-To: <20220429133552.33768-1-zhengqi.arch@bytedance.com> References: <20220429133552.33768-1-zhengqi.arch@bytedance.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: BE5D610002F X-Stat-Signature: b7gopze8enr5bzia4fun9e175k9x1e7x X-Rspam-User: Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=bytedance-com.20210112.gappssmtp.com header.s=20210112 header.b=7NbcGgSk; spf=pass (imf14.hostedemail.com: domain of zhengqi.arch@bytedance.com designates 209.85.216.48 as permitted sender) smtp.mailfrom=zhengqi.arch@bytedance.com; dmarc=pass (policy=none) header.from=bytedance.com X-HE-Tag: 1651239468-164442 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: The track_pte_set() is used to track the setting of the PTE page table entry, and the percpu_ref of the PTE page table page will be incremented when the entry changes from pte_none() to !pte_none(). The track_pte_clear() is used to track the clearing of the PTE page table entry, and the percpu_ref of the PTE page table page will be decremented when the entry changes from !pte_none() to pte_none(). In this way, the usage of the PTE page table page can be tracked by its percpu_ref. Signed-off-by: Qi Zheng --- include/linux/pte_ref.h | 14 ++++++++++++++ mm/pte_ref.c | 30 ++++++++++++++++++++++++++++++ 2 files changed, 44 insertions(+) diff --git a/include/linux/pte_ref.h b/include/linux/pte_ref.h index 379c3b45a6ab..6ab740e1b989 100644 --- a/include/linux/pte_ref.h +++ b/include/linux/pte_ref.h @@ -18,6 +18,10 @@ void __pte_put(pgtable_t page); void pte_put(pte_t *ptep); void try_to_free_user_pte(struct mm_struct *mm, pmd_t *pmd, unsigned long addr, bool switch_back); +void track_pte_set(struct mm_struct *mm, unsigned long addr, pte_t *ptep, + pte_t pte); +void track_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep, + pte_t pte); #else /* !CONFIG_FREE_USER_PTE */ @@ -54,6 +58,16 @@ static inline void try_to_free_user_pte(struct mm_struct *mm, pmd_t *pmd, { } +static inline void track_pte_set(struct mm_struct *mm, unsigned long addr, + pte_t *ptep, pte_t pte) +{ +} + +static inline void track_pte_clear(struct mm_struct *mm, unsigned long addr, + pte_t *ptep, pte_t pte) +{ +} + #endif /* CONFIG_FREE_USER_PTE */ #endif /* _LINUX_PTE_REF_H */ diff --git a/mm/pte_ref.c b/mm/pte_ref.c index bf9629272c71..e92510deda0b 100644 --- a/mm/pte_ref.c +++ b/mm/pte_ref.c @@ -197,4 +197,34 @@ void try_to_free_user_pte(struct mm_struct *mm, pmd_t *pmd, unsigned long addr, } } +void track_pte_set(struct mm_struct *mm, unsigned long addr, pte_t *ptep, + pte_t pte) +{ + pgtable_t page; + + if (&init_mm == mm || pte_huge(pte)) + return; + + page = pte_to_page(ptep); + BUG_ON(percpu_ref_is_zero(page->pte_ref)); + if (pte_none(*ptep) && !pte_none(pte)) + percpu_ref_get(page->pte_ref); +} +EXPORT_SYMBOL(track_pte_set); + +void track_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep, + pte_t pte) +{ + pgtable_t page; + + if (&init_mm == mm || pte_huge(pte)) + return; + + page = pte_to_page(ptep); + BUG_ON(percpu_ref_is_zero(page->pte_ref)); + if (!pte_none(pte)) + percpu_ref_put(page->pte_ref); +} +EXPORT_SYMBOL(track_pte_clear); + #endif /* CONFIG_FREE_USER_PTE */ -- 2.20.1