This patch shuffles some bits in vma->vm_flags
before patch:
0x00000200 0x01000000 0x20000000 0x40000000
x86 VM_NOHUGEPAGE VM_HUGEPAGE - VM_PAT
powerpc - - VM_SAO -
parisc VM_GROWSUP - - -
ia64 VM_GROWSUP - - -
nommu - VM_MAPPED_COPY - -
others - - - -
after patch:
0x00000200 0x01000000 0x20000000 0x40000000
x86 - VM_PAT VM_HUGEPAGE VM_NOHUGEPAGE
powerpc - VM_SAO - -
parisc - VM_GROWSUP - -
ia64 - VM_GROWSUP - -
nommu - VM_MAPPED_COPY - -
others - VM_ARCH_1 - -
And voila! One completely free bit.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxx>
---
include/linux/mm.h | 34 +++++++++++++++++++++-------------
mm/huge_memory.c | 2 +-
mm/ksm.c | 7 ++++++-
3 files changed, 28 insertions(+), 15 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index b8e5fe5..a444f47 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -70,6 +70,8 @@ extern unsigned int kobjsize(const void *objp);
/*
* vm_flags in vm_area_struct, see mm_types.h.
*/
+#define VM_NONE 0x00000000
+
#define VM_READ 0x00000001 /* currently active flags */
#define VM_WRITE 0x00000002
#define VM_EXEC 0x00000004
@@ -82,12 +84,6 @@ extern unsigned int kobjsize(const void *objp);
#define VM_MAYSHARE 0x00000080
#define VM_GROWSDOWN 0x00000100 /* general info on the segment */
-#if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)
-#define VM_GROWSUP 0x00000200
-#else
-#define VM_GROWSUP 0x00000000
-#define VM_NOHUGEPAGE 0x00000200 /* MADV_NOHUGEPAGE marked this vma */
-#endif
#define VM_PFNMAP 0x00000400 /* Page-ranges managed without "struct page", just pure PFN */
#define VM_DENYWRITE 0x00000800 /* ETXTBSY on write attempts.. */
@@ -106,20 +102,32 @@ extern unsigned int kobjsize(const void *objp);
#define VM_NORESERVE 0x00200000 /* should the VM suppress accounting */
#define VM_HUGETLB 0x00400000 /* Huge TLB Page VM */
#define VM_NONLINEAR 0x00800000 /* Is non-linear (remap_file_pages) */
-#ifndef CONFIG_TRANSPARENT_HUGEPAGE
-#define VM_MAPPED_COPY 0x01000000 /* T if mapped copy of data (nommu mmap) */
-#else
-#define VM_HUGEPAGE 0x01000000 /* MADV_HUGEPAGE marked this vma */
-#endif
+#define VM_ARCH_1 0x01000000 /* Architecture-specific flag */
#define VM_INSERTPAGE 0x02000000 /* The vma has had "vm_insert_page()" done on it */
#define VM_NODUMP 0x04000000 /* Do not include in the core dump */
#define VM_CAN_NONLINEAR 0x08000000 /* Has ->fault & does nonlinear pages */
#define VM_MIXEDMAP 0x10000000 /* Can contain "struct page" and pure PFN pages */
-#define VM_SAO 0x20000000 /* Strong Access Ordering (powerpc) */
-#define VM_PAT 0x40000000 /* PAT reserves whole VMA at once (x86) */
+#define VM_HUGEPAGE 0x20000000 /* MADV_HUGEPAGE marked this vma */
+#define VM_NOHUGEPAGE 0x40000000 /* MADV_NOHUGEPAGE marked this vma */
#define VM_MERGEABLE 0x80000000 /* KSM may merge identical pages */
+#if defined(CONFIG_X86)
+# define VM_PAT VM_ARCH_1 /* PAT reserves whole VMA at once (x86) */
+#elif defined(CONFIG_PPC)
+# define VM_SAO VM_ARCH_1 /* Strong Access Ordering (powerpc) */
+#elif defined(CONFIG_PARISC)
+# define VM_GROWSUP VM_ARCH_1
+#elif defined(CONFIG_IA64)
+# define VM_GROWSUP VM_ARCH_1
+#elif !defined(CONFIG_MMU)
+# define VM_MAPPED_COPY VM_ARCH_1 /* T if mapped copy of data (nommu mmap) */
+#endif
+
+#ifndef VM_GROWSUP
+# define VM_GROWSUP VM_NONE
+#endif
+
/* 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/mm/huge_memory.c b/mm/huge_memory.c
index cf827da..6ea5477 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1482,7 +1482,7 @@ out:
return ret;
}
-#define VM_NO_THP (VM_SPECIAL|VM_INSERTPAGE|VM_MIXEDMAP|VM_SAO| \
+#define VM_NO_THP (VM_SPECIAL|VM_INSERTPAGE|VM_MIXEDMAP| \
VM_HUGETLB|VM_SHARED|VM_MAYSHARE)
int hugepage_madvise(struct vm_area_struct *vma,
diff --git a/mm/ksm.c b/mm/ksm.c
index 47c8853..d1cbe2a 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -1470,9 +1470,14 @@ int ksm_madvise(struct vm_area_struct *vma, unsigned long start,
if (*vm_flags & (VM_MERGEABLE | VM_SHARED | VM_MAYSHARE |
VM_PFNMAP | VM_IO | VM_DONTEXPAND |
VM_RESERVED | VM_HUGETLB | VM_INSERTPAGE |
- VM_NONLINEAR | VM_MIXEDMAP | VM_SAO))
+ VM_NONLINEAR | VM_MIXEDMAP))
return 0; /* just ignore the advice */
+#ifdef VM_SAO
+ if (*vm_flags & VM_SAO)
+ return 0;
+#endif
+
if (!test_bit(MMF_VM_MERGEABLE, &mm->flags)) {
err = __ksm_enter(mm);
if (err)
--
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