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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 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 X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 460DE4000D X-Rspam-User: X-Stat-Signature: jg1axji9gyurky6pk5urn9jxomm9s4kr X-HE-Tag: 1767967995-847802 X-HE-Meta: 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 VQpSl8uO I4SLT8TN4+0Trk3nLxVJmVPCw+tUr58TJGEQ5ZU5fu0SUSLOpNkEywNTtJqBxKiGgOA4D7B+oy3D++88JU5fWtMLCathqV+VL1v/gNKatM09Em8Ci+rWn2R1i5fRwsiCLSXw//KK1HggjWAT8Aj6O7BUEV8egc+wz/wW9TLMVXucz1Z3b4+38L681LNoG6vf1m9N8+9KcXOOCN1WK6tODPmOd/D/YRm+g1h0YT7nD1+lr3+7n6ABQ5CjGqYFw4hMYr9mL 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: List-Subscribe: List-Unsubscribe: >> 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