[PATCH V3 4/5] mm: mmap: Add mmap flag to request VM_LOCKONFAULT

@@ -30,6 +30,7 @@
 #define MAP_NONBLOCK	0x40000		/* do not block on IO */
 #define MAP_STACK	0x80000		/* give out an address that is best suited for process/thread stacks */
 #define MAP_HUGETLB	0x100000	/* create a huge page mapping */
+#define MAP_LOCKONFAULT	0x200000	/* Lock pages after they are faulted in, do not prefault */
 
 #define MS_ASYNC	1		/* sync memory asynchronously */
 #define MS_SYNC		2		/* synchronous memory sync */

@@ -48,6 +48,7 @@
 #define MAP_NONBLOCK	0x20000		/* do not block on IO */
 #define MAP_STACK	0x40000		/* give out an address that is best suited for process/thread stacks */
 #define MAP_HUGETLB	0x80000		/* create a huge page mapping */
+#define MAP_LOCKONFAULT	0x100000	/* Lock pages after they are faulted in, do not prefault */
 
 /*
  * Flags for msync

@@ -24,6 +24,7 @@
 #define MAP_NONBLOCK	0x20000		/* do not block on IO */
 #define MAP_STACK	0x40000		/* give out an address that is best suited for process/thread stacks */
 #define MAP_HUGETLB	0x80000		/* create a huge page mapping */
+#define MAP_LOCKONFAULT	0x100000	/* Lock pages after they are faulted in, do not prefault */
 
 #define MS_SYNC		1		/* synchronous memory sync */
 #define MS_ASYNC	2		/* sync memory asynchronously */

@@ -31,5 +31,6 @@
 #define MAP_NONBLOCK	0x10000		/* do not block on IO */
 #define MAP_STACK	0x20000		/* give out an address that is best suited for process/thread stacks */
 #define MAP_HUGETLB	0x40000		/* create a huge page mapping */
+#define MAP_LOCKONFAULT	0x80000		/* Lock pages after they are faulted in, do not prefault */
 
 #endif /* _UAPI_ASM_POWERPC_MMAN_H */

@@ -26,6 +26,7 @@
 #define MAP_NONBLOCK	0x10000		/* do not block on IO */
 #define MAP_STACK	0x20000		/* give out an address that is best suited for process/thread stacks */
 #define MAP_HUGETLB	0x40000		/* create a huge page mapping */
+#define MAP_LOCKONFAULT	0x8000		/* Lock pages after they are faulted in, do not prefault */
 
 
 #endif /* _UAPI__SPARC_MMAN_H__ */

@@ -55,6 +55,7 @@
 #define MAP_NONBLOCK	0x20000		/* do not block on IO */
 #define MAP_STACK	0x40000		/* give out an address that is best suited for process/thread stacks */
 #define MAP_HUGETLB	0x80000		/* create a huge page mapping */
+#define MAP_LOCKONFAULT	0x100000	/* Lock pages after they are faulted in, do not prefault */
 #ifdef CONFIG_MMAP_ALLOW_UNINITIALIZED
 # define MAP_UNINITIALIZED 0x4000000	/* For anonymous mmap, memory could be
 					 * uninitialized */

@@ -86,7 +86,8 @@ calc_vm_flag_bits(unsigned long flags)
 {
 	return _calc_vm_trans(flags, MAP_GROWSDOWN,  VM_GROWSDOWN ) |
 	       _calc_vm_trans(flags, MAP_DENYWRITE,  VM_DENYWRITE ) |
-	       _calc_vm_trans(flags, MAP_LOCKED,     VM_LOCKED    );
+	       _calc_vm_trans(flags, MAP_LOCKED,     VM_LOCKED    ) |
+	       _calc_vm_trans(flags, MAP_LOCKONFAULT,VM_LOCKONFAULT);
 }
 
 unsigned long vm_commit_limit(void);

@@ -12,6 +12,7 @@
 #define MAP_NONBLOCK	0x10000		/* do not block on IO */
 #define MAP_STACK	0x20000		/* give out an address that is best suited for process/thread stacks */
 #define MAP_HUGETLB	0x40000		/* create a huge page mapping */
+#define MAP_LOCKONFAULT	0x80000		/* Lock pages after they are faulted in, do not prefault */
 
 /* Bits [26:31] are reserved, see mman-common.h for MAP_HUGETLB usage */
 

@@ -1301,7 +1301,7 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
 	vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) |
 			mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
 
-	if (flags & MAP_LOCKED)
+	if (flags & (MAP_LOCKED | MAP_LOCKONFAULT))
 		if (!can_do_mlock())
 			return -EPERM;