From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 826A133438D; Fri, 9 Jan 2026 14:13:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767967994; cv=none; b=UwWLNntCFBloc+zrWW9pnP/BzbM34J1jjiCLvnYAXfX71vC3YIXamOJ/7PuIoCaR+OCc400DEMNs+aAqIopk+y5d7mk89HtYI97Nq7CL3hKxd/7+Y/JBc9bhb4QtcQ7+uMLC0s48p7suHEUoxamSMSwLcfMBZbrNSdbYM/vfJw8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767967994; c=relaxed/simple; bh=zfTrIma4u2eTRFK2jPd6kgFySsJEA/u5aLMa3tKAV2c=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=aXbI2O37UQr3F8tk9w+8a8vaqC1USwZqPlBJVn6RZdz8Yv2hp6XmABZdQPyBLO90+XUmJQkgcFF/PjHKEwwWXpFcBg79BvI2KHNCOiAqgVzjjVu4YunSg7Lxrx44V0Oo2uRYN3tc6IsnZl92DgkC3SvPj7Ybf1hSpHhxw7JoVMU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=r1AHF+d1; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="r1AHF+d1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E8359C4CEF1; Fri, 9 Jan 2026 14:13:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1767967994; bh=zfTrIma4u2eTRFK2jPd6kgFySsJEA/u5aLMa3tKAV2c=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=r1AHF+d1hLsa/qRNBXVzWxoX8nfLtX6asrbvdwVLhPc2yU0u1dnhdAnfH+rJQPPSh WB6i9K28hd6WwOEiKSERiESyR6hbSwjR0TgNnonOaasdFuZGy6eSM4Tv6klSdavMGk M5X3psDCH5aqO/uoD0Hf9W7f9tkHj7N31MdpByBdYhcCNmZMWJEnnBrEQsNNRw3JiP 1cOMZYTdEeY2kApQxbs5Z874kf/n78tLWpIROCuafDnqIKFGvYv67ATprzishHzrfl RY0vegzRUMy3pFvkjPX65p1gakoT+H+U8+eqvaAZbLsFWBhxAn4rciU42PC8+mKvlw rGENQuxdown3Q== Message-ID: <4d94363b-5b3b-4401-a9d8-da136d71f8c3@kernel.org> Date: Fri, 9 Jan 2026 15:13:04 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RESEND v3 1/2] mm/tlb: skip redundant IPI when TLB flush already synchronized To: Lance Yang Cc: dave.hansen@intel.com, dave.hansen@linux.intel.com, will@kernel.org, aneesh.kumar@kernel.org, npiggin@gmail.com, peterz@infradead.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, arnd@arndb.de, akpm@linux-foundation.org, lorenzo.stoakes@oracle.com, ziy@nvidia.com, baolin.wang@linux.alibaba.com, Liam.Howlett@oracle.com, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, shy828301@gmail.com, riel@surriel.com, jannh@google.com, linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, ioworker0@gmail.com References: <20260106120303.38124-1-lance.yang@linux.dev> <20260106120303.38124-2-lance.yang@linux.dev> <7472056a-3919-429a-845d-c2076496d537@linux.dev> From: "David Hildenbrand (Red Hat)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit >> What could work is tracking "tlb_table_flush_sent_ipi" really when we >> are flushing the TLB for removed/unshared tables, and maybe resetting >> it ... I don't know when from the top of my head. > > Not sure what's the best way forward here :( > >> >> v2 was simpler IMHO. > > The main concern Dave raised was that with PV hypercalls or when > INVLPGB is available, we can't tell from a static check whether IPIs > were actually sent. Why can't we set the boolean at runtime when initializing the pv_ops structure, when we are sure that it is allowed? -- Cheers David