fork: reset mm->pinned_vm
mm->pinned_vm counts pages of mm's address space that were permanently pinned in memory by increasing their reference counter. The counter was introduced by commit bc3e53f6 ("mm: distinguish between mlocked and pinned pages"), while before it locked_vm had been used for such pages. Obviously, we should reset the counter on fork if !CLONE_VM, just like we do with locked_vm, but currently we don't. Let's fix it. This patch will fix the contents of /proc/pid/status:VmPin. ib_umem_get[infiniband] and perf_mmap still check pinned_vm against RLIMIT_MEMLOCK. It's left from the times when pinned pages were accounted under locked_vm, but today it looks wrong. It isn't clear how we should deal with it. We still have some drivers accounting pinned pages under mm->locked_vm - this is what commit bc3e53f6 was fighting against. It's infiniband/usnic and vfio. Signed-off-by: NVladimir Davydov <vdavydov@parallels.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Roland Dreier <roland@kernel.org> Cc: Sean Hefty <sean.hefty@intel.com> Cc: Hal Rosenstock <hal.rosenstock@gmail.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Showing
想要评论请 注册 或 登录