linux-kernel - [PATCH v2 04/19] mm: Allow THP orders for PFNMAPs

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Message-ID: <20240826204353.2228736-5-peterx@redhat.com>
Date: Mon, 26 Aug 2024 16:43:38 -0400
From: Peter Xu <peterx@...hat.com>
To: linux-kernel@...r.kernel.org,
	linux-mm@...ck.org
Cc: Gavin Shan <gshan@...hat.com>,
	Catalin Marinas <catalin.marinas@....com>,
	x86@...nel.org,
	Ingo Molnar <mingo@...hat.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Paolo Bonzini <pbonzini@...hat.com>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Alistair Popple <apopple@...dia.com>,
	kvm@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	Sean Christopherson <seanjc@...gle.com>,
	peterx@...hat.com,
	Oscar Salvador <osalvador@...e.de>,
	Jason Gunthorpe <jgg@...dia.com>,
	Borislav Petkov <bp@...en8.de>,
	Zi Yan <ziy@...dia.com>,
	Axel Rasmussen <axelrasmussen@...gle.com>,
	David Hildenbrand <david@...hat.com>,
	Yan Zhao <yan.y.zhao@...el.com>,
	Will Deacon <will@...nel.org>,
	Kefeng Wang <wangkefeng.wang@...wei.com>,
	Alex Williamson <alex.williamson@...hat.com>,
	Matthew Wilcox <willy@...radead.org>,
	Ryan Roberts <ryan.roberts@....com>
Subject: [PATCH v2 04/19] mm: Allow THP orders for PFNMAPs

This enables PFNMAPs to be mapped at either pmd/pud layers.  Generalize the
dax case into vma_is_special_huge() so as to cover both.  Meanwhile, rename
the macro to THP_ORDERS_ALL_SPECIAL.

Cc: Matthew Wilcox <willy@...radead.org>
Cc: Gavin Shan <gshan@...hat.com>
Cc: Ryan Roberts <ryan.roberts@....com>
Cc: David Hildenbrand <david@...hat.com>
Cc: Zi Yan <ziy@...dia.com>
Reviewed-by: Jason Gunthorpe <jgg@...dia.com>
Signed-off-by: Peter Xu <peterx@...hat.com>
---
 include/linux/huge_mm.h | 6 +++---
 mm/huge_memory.c        | 4 ++--
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index b550b5a248bb..4da102b74a8c 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -76,9 +76,9 @@ extern struct kobj_attribute thpsize_shmem_enabled_attr;
 /*
  * Mask of all large folio orders supported for file THP. Folios in a DAX
  * file is never split and the MAX_PAGECACHE_ORDER limit does not apply to
- * it.
+ * it.  Same to PFNMAPs where there's neither page* nor pagecache.
  */
-#define THP_ORDERS_ALL_FILE_DAX		\
+#define THP_ORDERS_ALL_SPECIAL		\
 	(BIT(PMD_ORDER) | BIT(PUD_ORDER))
 #define THP_ORDERS_ALL_FILE_DEFAULT	\
 	((BIT(MAX_PAGECACHE_ORDER + 1) - 1) & ~BIT(0))
@@ -87,7 +87,7 @@ extern struct kobj_attribute thpsize_shmem_enabled_attr;
  * Mask of all large folio orders supported for THP.
  */
 #define THP_ORDERS_ALL	\
-	(THP_ORDERS_ALL_ANON | THP_ORDERS_ALL_FILE_DAX | THP_ORDERS_ALL_FILE_DEFAULT)
+	(THP_ORDERS_ALL_ANON | THP_ORDERS_ALL_SPECIAL | THP_ORDERS_ALL_FILE_DEFAULT)
 
 #define TVA_SMAPS		(1 << 0)	/* Will be used for procfs */
 #define TVA_IN_PF		(1 << 1)	/* Page fault handler */
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index dec17d09390f..e2c314f631f3 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -96,8 +96,8 @@ unsigned long __thp_vma_allowable_orders(struct vm_area_struct *vma,
 	/* Check the intersection of requested and supported orders. */
 	if (vma_is_anonymous(vma))
 		supported_orders = THP_ORDERS_ALL_ANON;
-	else if (vma_is_dax(vma))
-		supported_orders = THP_ORDERS_ALL_FILE_DAX;
+	else if (vma_is_special_huge(vma))
+		supported_orders = THP_ORDERS_ALL_SPECIAL;
 	else
 		supported_orders = THP_ORDERS_ALL_FILE_DEFAULT;
 
-- 
2.45.0