mm: kill vma flag VM_RESERVED and mm->reserved_vm counter

A long time ago, in v2.4, VM_RESERVED kept swapout process off VMA,
currently it lost original meaning but still has some effects:

 | effect                 | alternative flags
-+------------------------+---------------------------------------------
1| account as reserved_vm | VM_IO
2| skip in core dump      | VM_IO, VM_DONTDUMP
3| do not merge or expand | VM_IO, VM_DONTEXPAND, VM_HUGETLB, VM_PFNMAP
4| do not mlock           | VM_IO, VM_DONTEXPAND, VM_HUGETLB, VM_PFNMAP

This patch removes reserved_vm counter from mm_struct.  Seems like nobody
cares about it, it does not exported into userspace directly, it only
reduces total_vm showed in proc.

Thus VM_RESERVED can be replaced with VM_IO or pair VM_DONTEXPAND | VM_DONTDUMP.

remap_pfn_range() and io_remap_pfn_range() set VM_IO|VM_DONTEXPAND|VM_DONTDUMP.
remap_vmalloc_range() set VM_DONTEXPAND | VM_DONTDUMP.

[akpm@linux-foundation.org: drivers/vfio/pci/vfio_pci.c fixup]
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Carsten Otte <cotte@de.ibm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Eric Paris <eparis@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Kentaro Takeda <takedakn@nttdata.co.jp>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Venkatesh Pallipadi <venki@google.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 2 insertions, 4 deletions

diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h
index 95b738c7abff..ba7a0ff19d39 100644
--- a/include/linux/mempolicy.h
+++ b/include/linux/mempolicy.h
@@ -239,7 +239,7 @@ extern int mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol,
 /* Check if a vma is migratable */
 static inline int vma_migratable(struct vm_area_struct *vma)
 {
-        if (vma->vm_flags & (VM_IO|VM_HUGETLB|VM_PFNMAP|VM_RESERVED))
+        if (vma->vm_flags & (VM_IO | VM_HUGETLB | VM_PFNMAP))
                 return 0;
         /*
          * Migration allocates pages in the highest zone. If we cannot
diff --git a/include/linux/mm.h b/include/linux/mm.h
index dc08d558e058..0514fe9d3c84 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -96,7 +96,6 @@ extern unsigned int kobjsize(const void *objp);
 
 #define VM_DONTCOPY     0x00020000      /* Do not copy this vma on fork */
 #define VM_DONTEXPAND   0x00040000      /* Cannot expand with mremap() */
-#define VM_RESERVED     0x00080000      /* Count as reserved_vm like IO */
 #define VM_ACCOUNT      0x00100000      /* Is a VM accounted object */
 #define VM_NORESERVE    0x00200000      /* should the VM suppress accounting */
 #define VM_HUGETLB      0x00400000      /* Huge TLB Page VM */
@@ -148,7 +147,7 @@ extern unsigned int kobjsize(const void *objp);
  * Special vmas that are non-mergable, non-mlock()able.
  * Note: mm/huge_memory.c VM_NO_THP depends on this definition.
  */
-#define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_RESERVED | VM_PFNMAP)
+#define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_PFNMAP)
 
 /*
  * mapping from the currently active vm_flags protection bits (the
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 58d3173eb365..a57a43f5ca7c 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -349,7 +349,6 @@ struct mm_struct {
         unsigned long shared_vm;        /* Shared pages (files) */
         unsigned long exec_vm;          /* VM_EXEC & ~VM_WRITE */
         unsigned long stack_vm;         /* VM_GROWSUP/DOWN */
-        unsigned long reserved_vm;      /* VM_RESERVED|VM_IO pages */
         unsigned long def_flags;
         unsigned long nr_ptes;          /* Page table pages */
         unsigned long start_code, end_code, start_data, end_data;