diff options
| author | Davidlohr Bueso <dave@stgolabs.net> | 2019-02-06 09:59:15 -0800 |
|---|---|---|
| committer | Jason Gunthorpe <jgg@mellanox.com> | 2019-02-07 12:54:02 -0700 |
| commit | 70f8a3ca68d3e1f3344d959981ca55d5f6ec77f7 (patch) | |
| tree | 5c43234a8f1697bf3d1a4a8926a014b922b046ff /drivers/infiniband/hw/qib | |
| parent | a2bfd708b17adb6e597e70d4eca824667f2d4e3c (diff) | |
mm: make mm->pinned_vm an atomic64 counter
Taking a sleeping lock to _only_ increment a variable is quite the
overkill, and pretty much all users do this. Furthermore, some drivers
(ie: infiniband and scif) that need pinned semantics can go to quite
some trouble to actually delay via workqueue (un)accounting for pinned
pages when not possible to acquire it.
By making the counter atomic we no longer need to hold the mmap_sem and
can simply some code around it for pinned_vm users. The counter is 64-bit
such that we need not worry about overflows such as rdma user input
controlled from userspace.
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Diffstat (limited to 'drivers/infiniband/hw/qib')
| -rw-r--r-- | drivers/infiniband/hw/qib/qib_user_pages.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/infiniband/hw/qib/qib_user_pages.c b/drivers/infiniband/hw/qib/qib_user_pages.c index 075f09fb7ce3..c6c81022d313 100644 --- a/drivers/infiniband/hw/qib/qib_user_pages.c +++ b/drivers/infiniband/hw/qib/qib_user_pages.c @@ -75,7 +75,7 @@ static int __qib_get_user_pages(unsigned long start_page, size_t num_pages, goto bail_release; } - current->mm->pinned_vm += num_pages; + atomic64_add(num_pages, ¤t->mm->pinned_vm); ret = 0; goto bail; @@ -156,7 +156,7 @@ 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->pinned_vm -= num_pages; + atomic64_sub(num_pages, ¤t->mm->pinned_vm); up_write(¤t->mm->mmap_sem); } } |