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[34.78.232.44]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-390e47b6ce3sm17286057f8f.43.2025.03.04.04.52.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 04 Mar 2025 04:52:51 -0800 (PST) Date: Tue, 4 Mar 2025 12:52:47 +0000 From: Brendan Jackman To: Dave Hansen Cc: Borislav Petkov , Rik van Riel , x86@kernel.org, linux-kernel@vger.kernel.org, peterz@infradead.org, dave.hansen@linux.intel.com, zhengqi.arch@bytedance.com, nadav.amit@gmail.com, thomas.lendacky@amd.com, kernel-team@meta.com, linux-mm@kvack.org, akpm@linux-foundation.org, jannh@google.com, mhklinux@outlook.com, andrew.cooper3@citrix.com, Manali.Shukla@amd.com, mingo@kernel.org Subject: Re: [PATCH v14 11/13] x86/mm: do targeted broadcast flushing from tlbbatch code Message-ID: References: <20250226030129.530345-1-riel@surriel.com> <20250226030129.530345-12-riel@surriel.com> <20250303114618.GBZ8WWihMDjf-oy8P0@fat_crate.local> <7e1ca8c7-6f3e-44dc-9dd8-bd273a03a83e@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7e1ca8c7-6f3e-44dc-9dd8-bd273a03a83e@intel.com> X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 1E3B214001F X-Stat-Signature: 6qx1fybobq3dow9j9bxs9h6cqug67crh X-Rspam-User: X-HE-Tag: 1741092772-16700 X-HE-Meta: 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 MyWf+9J3 Rm5xNTg9Ue/V0ZJeuaHhbkubEWMgHezI31IAPCIUNTrxfp7cxcBHbwuVxFdFO81jjObJkowo4AI3xYlSHfuvtrZqA5Cxkj0K9F/Qh8Y1E/28phKhTprcfm5ZhzGPjC5zp/rIiyIIrKbTum5QE0FhAwlA840E39CgoSDMrqv1WQ2Ydh4ANEgVnSpkAixEUw9F1EbakwxqGqemxPOrb89eW7x3K2emV7rS3uVj4jnaKHrm+VSVzZaAxqAZIauCTh51WzWH8ClJULwre/oXrIT2MgCHyKjWCxKcSLGnsT6RPYtw0heNgMcwMYfixwMzx4WTCu+bnj1TELMANrZbONv9JmP67uZP1xO98CqHagw92MMqbXzxmJeqtyQVBSWnKCnG4e7PTpI+gS1+hOT4pcyH//lH3/4XIw21qgPWPozt5WjQwgBFfbMgc59WGClsxqSm6RrCUnYRepOXScoOWFAMHSbCjsQswUAxwJFLm 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: On Mon, Mar 03, 2025 at 01:47:42PM -0800, Dave Hansen wrote: > > static void broadcast_tlb_flush(struct flush_tlb_info *info) > > { > > bool pmd = info->stride_shift == PMD_SHIFT; > > @@ -790,6 +821,8 @@ void switch_mm_irqs_off(struct mm_struct *unused, struct mm_struct *next, > > if (IS_ENABLED(CONFIG_PROVE_LOCKING)) > > WARN_ON_ONCE(!irqs_disabled()); > > > > + tlbsync(); > > This one is in dire need of comments. I have been advocating to move this to a place where it's clearer. I also think it needs comments: https://lore.kernel.org/all/CA+i-1C31TrceZiizC_tng_cc-zcvKsfXLAZD_XDftXnp9B2Tdw@mail.gmail.com/