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mm: distinguish between mlocked and pinned pages

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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>
This commit is contained in:
Christoph Lameter 2011-10-31 17:07:30 -07:00 committed by Linus Torvalds
parent f11c0ca501
commit bc3e53f682
6 changed files with 14 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
drivers/infiniband/core/umem.c
View File

@ -136,7 +136,7 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
down_write(&current->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(&current->mm->mmap_sem);
if (vma_list)
@ -222,7 +222,7 @@ static void ib_umem_account(struct work_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);

6
drivers/infiniband/hw/ipath/ipath_user_pages.c
View File

@ -79,7 +79,7 @@ static int __ipath_get_user_pages(unsigned long start_page, size_t num_pages,
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 page **p, size_t num_pages)
__ipath_release_user_pages(p, num_pages, 1);
current->mm->locked_vm -= num_pages;
current->mm->pinned_vm -= num_pages;
up_write(&current->mm->mmap_sem);
}
@ -195,7 +195,7 @@ static void user_pages_account(struct work_struct *_work)
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);

4
drivers/infiniband/hw/qib/qib_user_pages.c
View File

@ -74,7 +74,7 @@ static int __qib_get_user_pages(unsigned long start_page, size_t num_pages,
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 **p, size_t num_pages)
__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(&current->mm->mmap_sem);
}
}

2
fs/proc/task_mmu.c
View File

@ -44,6 +44,7 @@ void task_mem(struct seq_file *m, struct mm_struct *mm)
"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 mm_struct *mm)
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),

2
include/linux/mm_types.h
View File

@ -304,7 +304,7 @@ 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;

6
kernel/events/core.c
View File

@ -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)