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Message-ID: <da92b66f3ab0f51292d82ff9267ea1a15ec7e81c.1729760996.git.qinyuntan@linux.alibaba.com>
Date: Thu, 24 Oct 2024 17:34:43 +0800
From: Qinyun Tan <qinyuntan@...ux.alibaba.com>
To: Andrew Morton <akpm@...ux-foundation.org>,
Alex Williamson <alex.williamson@...hat.com>
Cc: linux-mm@...ck.org,
kvm@...r.kernel.org,
linux-kernel@...r.kernel.org,
Qinyun Tan <qinyuntan@...ux.alibaba.com>,
Guanghui Feng <guanghuifeng@...ux.alibaba.com>,
Xunlei Pang <xlpang@...ux.alibaba.com>
Subject: [PATCH v1: vfio: avoid unnecessary pin memory when dma map io address space 1/2] mm: introduce vma flag VM_PGOFF_IS_PFN
Introduce a new vma flag 'VM_PGOFF_IS_PFN', which means
vma->vm_pgoff == pfn. This allows us to directly obtain pfn
through vma->vm_pgoff. No Functional Change.
Signed-off-by: Qinyun Tan <qinyuntan@...ux.alibaba.com>
Reviewed-by: Guanghui Feng <guanghuifeng@...ux.alibaba.com>
Reviewed-by: Xunlei Pang <xlpang@...ux.alibaba.com>
---
include/linux/mm.h | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index ecf63d2b05825..80849b1b9aa92 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -322,6 +322,12 @@ extern unsigned int kobjsize(const void *objp);
#define VM_NOHUGEPAGE 0x40000000 /* MADV_NOHUGEPAGE marked this vma */
#define VM_MERGEABLE 0x80000000 /* KSM may merge identical pages */
+#ifdef CONFIG_ARCH_USES_HIGH_VMA_FLAGS /* vma->vm_pgoff == pfn */
+ #define VM_PGOFF_IS_PFN BIT(62)
+#else
+ #define VM_PGOFF_IS_PFN VM_NONE
+#endif
+
#ifdef CONFIG_ARCH_USES_HIGH_VMA_FLAGS
#define VM_HIGH_ARCH_BIT_0 32 /* bit only usable on 64-bit architectures */
#define VM_HIGH_ARCH_BIT_1 33 /* bit only usable on 64-bit architectures */
--
2.43.5
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