The patch titled
Subject: mm: mmap: add mmap flag to request VM_LOCKONFAULT
has been added to the -mm tree. Its filename is
mm-mmap-add-mmap-flag-to-request-vm_lockonfault.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-mmap-add-mmap-flag-to-request-vm_lockonfault.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-mmap-add-mmap-flag-to-request-vm_lockonfault.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
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------------------------------------------------------
From: Eric B Munson <emunson@xxxxxxxxxx>
Subject: mm: mmap: add mmap flag to request VM_LOCKONFAULT
The cost of faulting in all memory to be locked can be very high when
working with large mappings. If only portions of the mapping will be used
this can incur a high penalty for locking.
Now that we have the new VMA flag for the locked but not present state,
expose it as an mmap option like MAP_LOCKED -> VM_LOCKED.
Signed-off-by: Eric B Munson <emunson@xxxxxxxxxx>
Cc: Shuah Khan <shuahkh@xxxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Michael Kerrisk <mtk.manpages@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/alpha/include/uapi/asm/mman.h | 1 +
arch/mips/include/uapi/asm/mman.h | 1 +
arch/parisc/include/uapi/asm/mman.h | 1 +
arch/powerpc/include/uapi/asm/mman.h | 1 +
arch/sparc/include/uapi/asm/mman.h | 1 +
arch/xtensa/include/uapi/asm/mman.h | 1 +
include/linux/mman.h | 3 ++-
include/uapi/asm-generic/mman.h | 1 +
mm/mmap.c | 2 +-
9 files changed, 10 insertions(+), 2 deletions(-)
diff -puN arch/alpha/include/uapi/asm/mman.h~mm-mmap-add-mmap-flag-to-request-vm_lockonfault arch/alpha/include/uapi/asm/mman.h
--- a/arch/alpha/include/uapi/asm/mman.h~mm-mmap-add-mmap-flag-to-request-vm_lockonfault
+++ a/arch/alpha/include/uapi/asm/mman.h
@@ -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 */
diff -puN arch/mips/include/uapi/asm/mman.h~mm-mmap-add-mmap-flag-to-request-vm_lockonfault arch/mips/include/uapi/asm/mman.h
--- a/arch/mips/include/uapi/asm/mman.h~mm-mmap-add-mmap-flag-to-request-vm_lockonfault
+++ a/arch/mips/include/uapi/asm/mman.h
@@ -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
diff -puN arch/parisc/include/uapi/asm/mman.h~mm-mmap-add-mmap-flag-to-request-vm_lockonfault arch/parisc/include/uapi/asm/mman.h
--- a/arch/parisc/include/uapi/asm/mman.h~mm-mmap-add-mmap-flag-to-request-vm_lockonfault
+++ a/arch/parisc/include/uapi/asm/mman.h
@@ -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 */
diff -puN arch/powerpc/include/uapi/asm/mman.h~mm-mmap-add-mmap-flag-to-request-vm_lockonfault arch/powerpc/include/uapi/asm/mman.h
--- a/arch/powerpc/include/uapi/asm/mman.h~mm-mmap-add-mmap-flag-to-request-vm_lockonfault
+++ a/arch/powerpc/include/uapi/asm/mman.h
@@ -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 */
diff -puN arch/sparc/include/uapi/asm/mman.h~mm-mmap-add-mmap-flag-to-request-vm_lockonfault arch/sparc/include/uapi/asm/mman.h
--- a/arch/sparc/include/uapi/asm/mman.h~mm-mmap-add-mmap-flag-to-request-vm_lockonfault
+++ a/arch/sparc/include/uapi/asm/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__ */
diff -puN arch/xtensa/include/uapi/asm/mman.h~mm-mmap-add-mmap-flag-to-request-vm_lockonfault arch/xtensa/include/uapi/asm/mman.h
--- a/arch/xtensa/include/uapi/asm/mman.h~mm-mmap-add-mmap-flag-to-request-vm_lockonfault
+++ a/arch/xtensa/include/uapi/asm/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 */
diff -puN include/linux/mman.h~mm-mmap-add-mmap-flag-to-request-vm_lockonfault include/linux/mman.h
--- a/include/linux/mman.h~mm-mmap-add-mmap-flag-to-request-vm_lockonfault
+++ a/include/linux/mman.h
@@ -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);
diff -puN include/uapi/asm-generic/mman.h~mm-mmap-add-mmap-flag-to-request-vm_lockonfault include/uapi/asm-generic/mman.h
--- a/include/uapi/asm-generic/mman.h~mm-mmap-add-mmap-flag-to-request-vm_lockonfault
+++ a/include/uapi/asm-generic/mman.h
@@ -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 */
diff -puN mm/mmap.c~mm-mmap-add-mmap-flag-to-request-vm_lockonfault mm/mmap.c
--- a/mm/mmap.c~mm-mmap-add-mmap-flag-to-request-vm_lockonfault
+++ a/mm/mmap.c
@@ -1301,7 +1301,7 @@ unsigned long do_mmap_pgoff(struct file
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;
_
Patches currently in -mm which might be from emunson@xxxxxxxxxx are
mm-mlock-refactor-mlock-munlock-and-munlockall-code.patch
mm-mlock-add-new-mlock-munlock-and-munlockall-system-calls.patch
mm-mlock-introduce-vm_lockonfault-and-add-mlock-flags-to-enable-it.patch
mm-mmap-add-mmap-flag-to-request-vm_lockonfault.patch
selftests-vm-add-tests-for-lock-on-fault.patch
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