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[80.230.25.21]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4891df9e50asm153245945e9.0.2026.04.21.15.01.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 21 Apr 2026 15:01:18 -0700 (PDT) Date: Tue, 21 Apr 2026 18:01:16 -0400 From: "Michael S. Tsirkin" To: linux-kernel@vger.kernel.org Cc: Andrew Morton , David Hildenbrand , Vlastimil Babka , Brendan Jackman , Michal Hocko , Suren Baghdasaryan , Jason Wang , Andrea Arcangeli , Gregory Price , linux-mm@kvack.org, virtualization@lists.linux.dev, Lorenzo Stoakes , "Liam R. Howlett" , Mike Rapoport Subject: [PATCH RFC v3 02/19] mm: add folio_zero_user stub for configs without THP/HUGETLBFS Message-ID: <2c8e630afa8b68232d648c08eec4b2fc7d933dc1.1776808210.git.mst@redhat.com> References: 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: X-Mailer: git-send-email 2.27.0.106.g8ac3dc51b1 X-Mutt-Fcc: =sent folio_zero_user() is defined in mm/memory.c under CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS. A subsequent patch will call it from post_alloc_hook() for all user page zeroing, so configs without THP or HUGETLBFS will need a stub. Add a macro in the #else branch that falls back to clear_user_highpages(), which handles cache aliasing correctly on VIPT architectures and is always available via highmem.h. Without THP/HUGETLBFS, only order-0 user pages are allocated, so the locality optimization in the real folio_zero_user() (zero near the faulting address last) is not needed. Signed-off-by: Michael S. Tsirkin Assisted-by: Claude:claude-opus-4-6 Assisted-by: cursor-agent:GPT-5.4-xhigh --- include/linux/mm.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/include/linux/mm.h b/include/linux/mm.h index 5be3d8a8f806..541d36e5e420 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -4718,6 +4718,9 @@ static inline bool vma_is_special_huge(const struct vm_area_struct *vma) (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP))); } +#else /* !CONFIG_TRANSPARENT_HUGEPAGE && !CONFIG_HUGETLBFS */ +#define folio_zero_user(folio, addr_hint) \ + clear_user_highpages(&(folio)->page, (addr_hint), folio_nr_pages(folio)) #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */ #if MAX_NUMNODES > 1 -- MST