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Shutemov" To: Michael Roth Cc: linux-efi@vger.kernel.org, x86@kernel.org, linux-coco@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Ard Biesheuvel , Vlastimil Babka , Nikolay Borisov , stable@kernel.org, Tom Lendacky , Paolo Bonzini Subject: Re: [PATCH] efi/unaccepted: Fix off-by-one when checking for overlapping ranges Message-ID: <20231103145353.5wzcwc5znkzt6vzf@box> References: <20231103142650.108394-1-michael.roth@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231103142650.108394-1-michael.roth@amd.com> X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 9349440021 X-Stat-Signature: cotegwgbahs6yhkngca5btujpap6zgkm X-Rspam-User: X-HE-Tag: 1699023241-779403 X-HE-Meta: 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 NEDJbjQb ROFOMzYJAhyzBEbLAvGQLi/ZAzj2XZrhVCzGh0Yy+W6KKrivqtFVLLNWISGzkPzgW0q3j5Rw4E+8L/XG/ZCoxR0cmoWdMsroQmoAgBVTwidF3V94yKgOqKlL5qwz17zGXB7rl+S6uAcT/QpQK1TwE+jHCMa2UnRbOLnRV5tPoGzt51zXhmUtoHz5PZwWjnAySexo+uP+idYsT4VJ0Bnjg6jkEmV++qXwefEXCeFQNR7RLNkiK68jqaImgZTXP6VOqg7qMks0i9o/FzoFTxGZZVgCccg== 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 Fri, Nov 03, 2023 at 09:26:50AM -0500, Michael Roth wrote: > When a thread needs to accept memory it will scan the accepting_list > to see if any ranges already being processed by other threads overlap > with its range. Due to an off-by-one in the range comparisons, a thread > might falsely determine that an overlapping range is being accepted, > leading to an unnecessary delay before it begins processing the range. Maybe s/thread/task/g ? > Fix the off-by-one in the range comparison to prevent this and slightly > improve performance. > > Fixes: 50e782a86c98 ("efi/unaccepted: Fix soft lockups caused by parallel memory acceptance") > Link: https://lore.kernel.org/linux-mm/20231101004523.vseyi5bezgfaht5i@amd.com/T/#me2eceb9906fcae5fe958b3fe88e41f920f8335b6 > Signed-off-by: Michael Roth Otherwise, looks good: Reviewed-by: Kirill A. Shutemov > -- Kiryl Shutsemau / Kirill A. Shutemov