[PATCH 06/46] mm: add VM_HUGETLB_HGM VMA flag

[James Houghton]

VM_HUGETLB_HGM indicates that a HugeTLB VMA may contain high-granularity
mappings. Its VmFlags string is "hm".

Signed-off-by: James Houghton <jthoughton@xxxxxxxxxx>
---
 fs/proc/task_mmu.c             | 3 +++
 include/linux/mm.h             | 7 +++++++
 include/trace/events/mmflags.h | 7 +++++++
 3 files changed, 17 insertions(+)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index e35a0398db63..41b5509bde0e 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -711,6 +711,9 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
 #ifdef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR
 		[ilog2(VM_UFFD_MINOR)]	= "ui",
 #endif /* CONFIG_HAVE_ARCH_USERFAULTFD_MINOR */
+#ifdef CONFIG_HUGETLB_HIGH_GRANULARITY_MAPPING
+		[ilog2(VM_HUGETLB_HGM)]	= "hm",
+#endif /* CONFIG_HUGETLB_HIGH_GRANULARITY_MAPPING */
 	};
 	size_t i;
 
diff --git a/include/linux/mm.h b/include/linux/mm.h
index c37f9330f14e..738b3605f80e 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -372,6 +372,13 @@ extern unsigned int kobjsize(const void *objp);
 # define VM_UFFD_MINOR		VM_NONE
 #endif /* CONFIG_HAVE_ARCH_USERFAULTFD_MINOR */
 
+#ifdef CONFIG_HUGETLB_HIGH_GRANULARITY_MAPPING
+# define VM_HUGETLB_HGM_BIT	38
+# define VM_HUGETLB_HGM		BIT(VM_HUGETLB_HGM_BIT)	/* HugeTLB high-granularity mapping */
+#else /* !CONFIG_HUGETLB_HIGH_GRANULARITY_MAPPING */
+# define VM_HUGETLB_HGM		VM_NONE
+#endif /* CONFIG_HUGETLB_HIGH_GRANULARITY_MAPPING */
+
 /* Bits set in the VMA until the stack is in its final location */
 #define VM_STACK_INCOMPLETE_SETUP	(VM_RAND_READ | VM_SEQ_READ)
 
diff --git a/include/trace/events/mmflags.h b/include/trace/events/mmflags.h
index 412b5a46374c..88ce04b2ff69 100644
--- a/include/trace/events/mmflags.h
+++ b/include/trace/events/mmflags.h
@@ -163,6 +163,12 @@ IF_HAVE_PG_SKIP_KASAN_POISON(PG_skip_kasan_poison, "skip_kasan_poison")
 # define IF_HAVE_UFFD_MINOR(flag, name)
 #endif
 
+#ifdef CONFIG_HUGETLB_HIGH_GRANULARITY_MAPPING
+# define IF_HAVE_HUGETLB_HGM(flag, name) {flag, name},
+#else
+# define IF_HAVE_HUGETLB_HGM(flag, name)
+#endif
+
 #define __def_vmaflag_names						\
 	{VM_READ,			"read"		},		\
 	{VM_WRITE,			"write"		},		\
@@ -187,6 +193,7 @@ IF_HAVE_UFFD_MINOR(VM_UFFD_MINOR,	"uffd_minor"	)		\
 	{VM_ACCOUNT,			"account"	},		\
 	{VM_NORESERVE,			"noreserve"	},		\
 	{VM_HUGETLB,			"hugetlb"	},		\
+IF_HAVE_HUGETLB_HGM(VM_HUGETLB_HGM,	"hugetlb_hgm"	)		\
 	{VM_SYNC,			"sync"		},		\
 	__VM_ARCH_SPECIFIC_1				,		\
 	{VM_WIPEONFORK,			"wipeonfork"	},		\
-- 
2.39.0.314.g84b9a713c41-goog