+ arm64-mm-override-arch_wants_pte_order.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: arm64/mm: override arch_wants_pte_order()
has been added to the -mm mm-unstable branch.  Its filename is
     arm64-mm-override-arch_wants_pte_order.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/arm64-mm-override-arch_wants_pte_order.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Ryan Roberts <ryan.roberts@arm.com>
Subject: arm64/mm: override arch_wants_pte_order()
Date: Fri, 29 Sep 2023 12:44:18 +0100

Define an arch-specific override of arch_wants_pte_order() so that when
anon_orders=recommend is set, large folios will be allocated for anonymous
memory with an order that is compatible with arm64's HPA uarch feature.

Link: https://lkml.kernel.org/r/20230929114421.3761121-8-ryan.roberts@arm.com
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: Yu Zhao <yuzhao@google.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Itaru Kitayama <itaru.kitayama@gmail.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/arm64/include/asm/pgtable.h |   10 ++++++++++
 1 file changed, 10 insertions(+)

--- a/arch/arm64/include/asm/pgtable.h~arm64-mm-override-arch_wants_pte_order
+++ a/arch/arm64/include/asm/pgtable.h
@@ -1110,6 +1110,16 @@ extern pte_t ptep_modify_prot_start(stru
 extern void ptep_modify_prot_commit(struct vm_area_struct *vma,
 				    unsigned long addr, pte_t *ptep,
 				    pte_t old_pte, pte_t new_pte);
+
+#define arch_wants_pte_order arch_wants_pte_order
+static inline int arch_wants_pte_order(void)
+{
+	/*
+	 * Many arm64 CPUs support hardware page aggregation (HPA), which can
+	 * coalesce 4 contiguous pages into a single TLB entry.
+	 */
+	return 2;
+}
 #endif /* !__ASSEMBLY__ */
 
 #endif /* __ASM_PGTABLE_H */
_

Patches currently in -mm which might be from ryan.roberts@arm.com are

mm-hugetlb-add-huge-page-size-param-to-set_huge_pte_at.patch
arm64-hugetlb-fix-set_huge_pte_at-to-work-with-all-swap-entries.patch
mm-allow-deferred-splitting-of-arbitrary-anon-large-folios.patch
mm-non-pmd-mappable-large-folios-for-folio_add_new_anon_rmap.patch
mm-thp-account-pte-mapped-anonymous-thp-usage.patch
mm-thp-introduce-anon_orders-and-anon_always_mask-sysfs-files.patch
mm-thp-extend-thp-to-allocate-anonymous-large-folios.patch
mm-thp-add-recommend-option-for-anon_orders.patch
arm64-mm-override-arch_wants_pte_order.patch
selftests-mm-cow-generalize-do_run_with_thp-helper.patch
selftests-mm-cow-add-tests-for-small-order-anon-thp.patch