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authorChristoph Lameter <cl@linux.com>2011-10-31 17:07:30 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-10-31 17:30:46 -0700
commitbc3e53f682d93df677dbd5006a404722b3adfe18 (patch)
treef386c29f13626e2b7d98d5a52525a78a9b59e447 /kernel
parentf11c0ca501af89fc07b0d9f17531ba3b68a4ef39 (diff)
mm: distinguish between mlocked and pinned pages
Some kernel components pin user space memory (infiniband and perf) (by increasing the page count) and account that memory as "mlocked". The difference between mlocking and pinning is: A. mlocked pages are marked with PG_mlocked and are exempt from swapping. Page migration may move them around though. They are kept on a special LRU list. B. Pinned pages cannot be moved because something needs to directly access physical memory. They may not be on any LRU list. I recently saw an mlockalled process where mm->locked_vm became bigger than the virtual size of the process (!) because some memory was accounted for twice: Once when the page was mlocked and once when the Infiniband layer increased the refcount because it needt to pin the RDMA memory. This patch introduces a separate counter for pinned pages and accounts them seperately. Signed-off-by: Christoph Lameter <cl@linux.com> Cc: Mike Marciniszyn <infinipath@qlogic.com> Cc: Roland Dreier <roland@kernel.org> Cc: Sean Hefty <sean.hefty@intel.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/events/core.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index d1a1bee3522..12a0287e035 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3544,7 +3544,7 @@ static void perf_mmap_close(struct vm_area_struct *vma)
struct ring_buffer *rb = event->rb;
atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm);
- vma->vm_mm->locked_vm -= event->mmap_locked;
+ vma->vm_mm->pinned_vm -= event->mmap_locked;
rcu_assign_pointer(event->rb, NULL);
mutex_unlock(&event->mmap_mutex);
@@ -3625,7 +3625,7 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
lock_limit = rlimit(RLIMIT_MEMLOCK);
lock_limit >>= PAGE_SHIFT;
- locked = vma->vm_mm->locked_vm + extra;
+ locked = vma->vm_mm->pinned_vm + extra;
if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
!capable(CAP_IPC_LOCK)) {
@@ -3651,7 +3651,7 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
atomic_long_add(user_extra, &user->locked_vm);
event->mmap_locked = extra;
event->mmap_user = get_current_user();
- vma->vm_mm->locked_vm += event->mmap_locked;
+ vma->vm_mm->pinned_vm += event->mmap_locked;
unlock:
if (!ret)