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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DF6EF109C032 for ; Wed, 25 Mar 2026 14:58:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=eO11bQx7sjhbWBYTR5ThY1PJIGNvBjQog7Wuvh14JpM=; b=yX1g8+avoxBhxoVbt53FoZyKAk n1n3AUG1RzJ30HdLhl97CWTOxeONnyxwMUh8+yNAfhE+s+0JZgnkKuS8TM6Mti0XFNvj1StD7YNys KM+OfhxJz+LaqU0RvXjpN2lmvQ9o08X6Mw03RyXMVzrUgw8WaNI3s3Hf9nrtw4+f/2lVIWamiYhab fYZ89lSxWMzClwQLEuvPdGVmKtaQGTRINEhlpCxTO3vUOv3HcfSGanePA8mIfE3h87AdR5T+iHOFr 9H93tKKVkjrAcJjXRuGbljzbJmPnaO+hsZVvEP49MYHtKzTm7m/0FzqXVXVS+TGmCs6fQaF6PVrPE 4GXdDMDg==; 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charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 3/25/26 15:36, Lorenzo Stoakes (Oracle) wrote: > On Mon, Mar 16, 2026 at 03:15:18PM +0100, David Hildenbrand (Arm) wrote: >> On 3/16/26 07:25, Baolin Wang wrote: >>> >>> >>> >>> Sure. However, after investigating RISC‑V and x86, I found that >>> ptep_clear_flush_young() does not flush the TLB on these architectures: >>> >>> int ptep_clear_flush_young(struct vm_area_struct *vma, >>>                unsigned long address, pte_t *ptep) >>> { >>>     /* >>>      * On x86 CPUs, clearing the accessed bit without a TLB flush >>>      * doesn't cause data corruption. [ It could cause incorrect >>>      * page aging and the (mistaken) reclaim of hot pages, but the >>>      * chance of that should be relatively low. ] >>>      * >>>      * So as a performance optimization don't flush the TLB when >>>      * clearing the accessed bit, it will eventually be flushed by >>>      * a context switch or a VM operation anyway. [ In the rare >>>      * event of it not getting flushed for a long time the delay >>>      * shouldn't really matter because there's no real memory >>>      * pressure for swapout to react to. ] >>>      */ >>>     return ptep_test_and_clear_young(vma, address, ptep); >>> } >> >> You'd probably want an arch helper then, that tells you whether >> a flush_tlb_range() after ptep_test_and_clear_young() is required. >> >> Or some special flush_tlb_range() helper. >> >> I agree that it requires more work. > > Sorry unclear here - does the series need more work or does a follow up patch > need more work? Follow up! -- Cheers, David