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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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7e1ca8c7-6f3e-44dc-9dd8-bd273a03a83e@intel.com> 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/