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@xxxxxxxxx>
---
drivers/infiniband/core/umem.c | 6 +++---
drivers/infiniband/hw/ipath/ipath_user_pages.c | 6 +++---
drivers/infiniband/hw/qib/qib_user_pages.c | 4 ++--
fs/proc/task_mmu.c | 2 ++
include/linux/mm_types.h | 2 +-
kernel/events/core.c | 6 +++---
6 files changed, 14 insertions(+), 12 deletions(-)
Index: linux-2.6/fs/proc/task_mmu.c
===================================================================
--- linux-2.6.orig/fs/proc/task_mmu.c 2011-08-10 14:08:42.000000000 -0500
+++ linux-2.6/fs/proc/task_mmu.c 2011-08-10 15:01:37.000000000 -0500
@@ -44,6 +44,7 @@ void task_mem(struct seq_file *m, struct
"VmPeak:\t%8lu kB\n"
"VmSize:\t%8lu kB\n"
"VmLck:\t%8lu kB\n"
+ "VmPin:\t%8lu kB\n"
"VmHWM:\t%8lu kB\n"
"VmRSS:\t%8lu kB\n"
"VmData:\t%8lu kB\n"
@@ -55,6 +56,7 @@ void task_mem(struct seq_file *m, struct
hiwater_vm << (PAGE_SHIFT-10),
(total_vm - mm->reserved_vm) << (PAGE_SHIFT-10),
mm->locked_vm << (PAGE_SHIFT-10),
+ mm->pinned_vm << (PAGE_SHIFT-10),
hiwater_rss << (PAGE_SHIFT-10),
total_rss << (PAGE_SHIFT-10),
data << (PAGE_SHIFT-10),
Index: linux-2.6/include/linux/mm_types.h
===================================================================
--- linux-2.6.orig/include/linux/mm_types.h 2011-08-10 14:08:42.000000000 -0500
+++ linux-2.6/include/linux/mm_types.h 2011-08-10 14:09:02.000000000 -0500
@@ -281,7 +281,7 @@ struct mm_struct {
unsigned long hiwater_rss; /* High-watermark of RSS usage */
unsigned long hiwater_vm; /* High-water virtual memory usage */
- unsigned long total_vm, locked_vm, shared_vm, exec_vm;
+ unsigned long total_vm, locked_vm, pinned_vm, shared_vm, exec_vm;
unsigned long stack_vm, reserved_vm, def_flags, nr_ptes;
unsigned long start_code, end_code, start_data, end_data;
unsigned long start_brk, brk, start_stack;
Index: linux-2.6/drivers/infiniband/core/umem.c
===================================================================
--- linux-2.6.orig/drivers/infiniband/core/umem.c 2011-08-10 14:08:57.000000000 -0500
+++ linux-2.6/drivers/infiniband/core/umem.c 2011-08-10 14:09:06.000000000 -0500
@@ -136,7 +136,7 @@ struct ib_umem *ib_umem_get(struct ib_uc
down_write(¤t->mm->mmap_sem);
- locked = npages + current->mm->locked_vm;
+ locked = npages + current->mm->pinned_vm;
lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
if ((locked > lock_limit) && !capable(CAP_IPC_LOCK)) {
@@ -206,7 +206,7 @@ out:
__ib_umem_release(context->device, umem, 0);
kfree(umem);
} else
- current->mm->locked_vm = locked;
+ current->mm->pinned_vm = locked;
up_write(¤t->mm->mmap_sem);
if (vma_list)
@@ -222,7 +222,7 @@ static void ib_umem_account(struct work_
struct ib_umem *umem = container_of(work, struct ib_umem, work);
down_write(&umem->mm->mmap_sem);
- umem->mm->locked_vm -= umem->diff;
+ umem->mm->pinned_vm -= umem->diff;
up_write(&umem->mm->mmap_sem);
mmput(umem->mm);
kfree(umem);
Index: linux-2.6/drivers/infiniband/hw/ipath/ipath_user_pages.c
===================================================================
--- linux-2.6.orig/drivers/infiniband/hw/ipath/ipath_user_pages.c 2011-08-10 14:08:57.000000000 -0500
+++ linux-2.6/drivers/infiniband/hw/ipath/ipath_user_pages.c 2011-08-10 14:09:06.000000000 -0500
@@ -79,7 +79,7 @@ static int __ipath_get_user_pages(unsign
goto bail_release;
}
- current->mm->locked_vm += num_pages;
+ current->mm->pinned_vm += num_pages;
ret = 0;
goto bail;
@@ -178,7 +178,7 @@ void ipath_release_user_pages(struct pag
__ipath_release_user_pages(p, num_pages, 1);
- current->mm->locked_vm -= num_pages;
+ current->mm->pinned_vm -= num_pages;
up_write(¤t->mm->mmap_sem);
}
@@ -195,7 +195,7 @@ static void user_pages_account(struct wo
container_of(_work, struct ipath_user_pages_work, work);
down_write(&work->mm->mmap_sem);
- work->mm->locked_vm -= work->num_pages;
+ work->mm->pinned_vm -= work->num_pages;
up_write(&work->mm->mmap_sem);
mmput(work->mm);
kfree(work);
Index: linux-2.6/drivers/infiniband/hw/qib/qib_user_pages.c
===================================================================
--- linux-2.6.orig/drivers/infiniband/hw/qib/qib_user_pages.c 2011-08-10 14:08:57.000000000 -0500
+++ linux-2.6/drivers/infiniband/hw/qib/qib_user_pages.c 2011-08-10 14:09:06.000000000 -0500
@@ -74,7 +74,7 @@ static int __qib_get_user_pages(unsigned
goto bail_release;
}
- current->mm->locked_vm += num_pages;
+ current->mm->pinned_vm += num_pages;
ret = 0;
goto bail;
@@ -151,7 +151,7 @@ void qib_release_user_pages(struct page
__qib_release_user_pages(p, num_pages, 1);
if (current->mm) {
- current->mm->locked_vm -= num_pages;
+ current->mm->pinned_vm -= num_pages;
up_write(¤t->mm->mmap_sem);
}
}
Index: linux-2.6/kernel/events/core.c
===================================================================
--- linux-2.6.orig/kernel/events/core.c 2011-08-10 14:08:57.000000000 -0500
+++ linux-2.6/kernel/events/core.c 2011-08-10 15:04:16.000000000 -0500
@@ -3500,7 +3500,7 @@ static void perf_mmap_close(struct vm_ar
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);
@@ -3581,7 +3581,7 @@ static int perf_mmap(struct file *file,
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)) {
@@ -3607,7 +3607,7 @@ static int perf_mmap(struct file *file,
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)
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>