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h=Date:From:To:Cc:Subject:References:In-Reply-To; b=b4o9VZqjwMqS7Z+uD2u5cG7IO8989ROX9lcwZgswwac+NecRR4mPBPIph8TmJzlN8 iLrAN7NiwUqGUHYOKBDhWMh5tp9xQJOCM9kqL4NPQC3LOK2yjr8tiubN4XAG2i9naE l7A89CXxWI4lXXWK+ZNUV1WsiBjiDvsCj4RrhvqxiolL+VbaUaNc/wo/MPsqKuYtQ+ y3dCxlxephQdRJRwb8Iw75WmkEANRoQbAR5qXgWouVp0whKw047FaqjlNnqt2aGb+e rNptH+PuZkZsU9ep8MPEl+ow5MtqHyRbLw2cHBvio/zizp6FcDTUYTKT1uiPd/bcn9 95dAxKvjuH5JQ== Date: Wed, 4 Nov 2026 10:22:20 +0100 From: "Oscar Salvador (SUSE)" To: Muchun Song Cc: Oscar Salvador , Andrew Morton , Mike Rapoport , Qi Zheng , Lance Yang , James Houghton , David Hildenbrand , Muchun Song , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 02/12] mm: hugetlb_vmemmap: unify VMEMMAP_{SPLIT,REMAP}_NO_TLB_FLUSH Message-ID: References: <20261104023510.260766-1-songmuchun@bytedance.com> <20261104023510.260766-3-songmuchun@bytedance.com> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261104023510.260766-3-songmuchun@bytedance.com> X-Spam-Status: No, score=-10.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: D182740005 X-Stat-Signature: y5f76pik773b8zzejpxcd69cz3hksj8t X-Rspam-User: X-HE-Tag: 1793784147-927454 X-HE-Meta: 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 xjU9IoYC fshgG8qk9IxCGS4sx0V5R2tbC/78gEDI7X4I1qMhL66NHYdNxkdkJRc7AXi+xjbwPerOTt8vJhgkSyHOeha/5BEOFQW9/Gb3aTkbGfyEclzaQqR/uH90RYyXC9vpMxUChMqtdIJnH8Jj0Kz8FNeiWOg7Y0xCcPQew9ApY0ofEZA9bt5604SYc6p+nmF/JcG1/HjtJN5g0o3eNwcgT+kbVH7UNeftD30Kr/2m5LS9pxC3QqBxS3O7wSqYy9zTaNY0aXv2FEOeGRH9lOyA3KZF1xR70xK3YyHo4zBniZi6nGlwbUlRQRJFAmaxVtsXqebOiPTQB Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Wed, Nov 04, 2026 at 10:35:00AM +0800, Muchun Song wrote: > VMEMMAP_SPLIT_NO_TLB_FLUSH and VMEMMAP_REMAP_NO_TLB_FLUSH do not > describe fully independent choices. A split-only walk can defer the > PMD-split flush to a later global flush, and a remap-only walk can > defer the final remap flush. However, when a PMD split is followed > by PTE remapping, the split flush must happen before the PTEs are > changed, because stale large-page translations must not overlap with > new small-page translations that map different physical pages. > > Replace the two flags with a single VMEMMAP_DEFER_TLB_FLUSH flag. The > new name reflects that only safely batchable flushes are deferred. Keep > split-only walks able to defer the flush, but force the split flush > whenever a remap_pte callback is present. Callers that batch HVO work > can still defer the final remap flush and issue their own global flush. > > Current callers keep the same flushing behavior. > > Signed-off-by: Muchun Song > Reviewed-by: Lance Yang > Reviewed-by: Qi Zheng Reviewed-by: Oscar Salvador -- Oscar Salvador SUSE Labs