mempolicy: rename mpol_free to mpol_put

This is a change that was requested some time ago by Mel Gorman.  Makes sense
to me, so here it is.

Note: I retain the name "mpol_free_shared_policy()" because it actually does
free the shared_policy, which is NOT a reference counted object.  However, ...

The mempolicy object[s] referenced by the shared_policy are reference counted,
so mpol_put() is used to release the reference held by the shared_policy.  The
mempolicy might not be freed at this time, because some task attached to the
shared object associated with the shared policy may be in the process of
allocating a page based on the mempolicy.  In that case, the task performing
the allocation will hold a reference on the mempolicy, obtained via
mpol_shared_policy_lookup().  The mempolicy will be freed when all tasks
holding such a reference have called mpol_put() for the mempolicy.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h
index 319fd34..507bf5e 100644 (file)
--- a/include/linux/mempolicy.h
+++ b/include/linux/mempolicy.h
@@ -71,7 +71,7 @@ struct mm_struct;
  *
  * Freeing policy:
  * Mempolicy objects are reference counted.  A mempolicy will be freed when
- * mpol_free() decrements the reference count to zero.
+ * mpol_put() decrements the reference count to zero.
  *
  * Copying policy objects:
  * mpol_copy() allocates a new mempolicy and copies the specified mempolicy
@@ -98,11 +98,11 @@ struct mempolicy {
  * The default fast path of a NULL MPOL_DEFAULT policy is always inlined.
  */
 
-extern void __mpol_free(struct mempolicy *pol);
-static inline void mpol_free(struct mempolicy *pol)
+extern void __mpol_put(struct mempolicy *pol);
+static inline void mpol_put(struct mempolicy *pol)
 {
        if (pol)
-               __mpol_free(pol);
+               __mpol_put(pol);
 }
 
 extern struct mempolicy *__mpol_copy(struct mempolicy *pol);
@@ -190,7 +190,7 @@ static inline int mpol_equal(struct mempolicy *a, struct mempolicy *b)
        return 1;
 }
 
-static inline void mpol_free(struct mempolicy *p)
+static inline void mpol_put(struct mempolicy *p)
 {
 }
 

diff --git a/kernel/exit.c b/kernel/exit.c
index 97f609f..2a9d98c 100644 (file)
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -967,7 +967,7 @@ NORET_TYPE void do_exit(long code)
        proc_exit_connector(tsk);
        exit_notify(tsk, group_dead);
 #ifdef CONFIG_NUMA
-       mpol_free(tsk->mempolicy);
+       mpol_put(tsk->mempolicy);
        tsk->mempolicy = NULL;
 #endif
 #ifdef CONFIG_FUTEX

diff --git a/kernel/fork.c b/kernel/fork.c
index c674aa8..1a5ae20 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1374,7 +1374,7 @@ bad_fork_cleanup_security:
        security_task_free(p);
 bad_fork_cleanup_policy:
 #ifdef CONFIG_NUMA
-       mpol_free(p->mempolicy);
+       mpol_put(p->mempolicy);
 bad_fork_cleanup_cgroup:
 #endif
        cgroup_exit(p, cgroup_callbacks_done);

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 8deae4e..53afa8c 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -116,7 +116,7 @@ static struct page *dequeue_huge_page_vma(struct vm_area_struct *vma,
                        break;
                }
        }
-       mpol_free(mpol);        /* unref if mpol !NULL */
+       mpol_put(mpol); /* unref if mpol !NULL */
        return page;
 }
 

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index c1b9077..ce2c5b6 100644 (file)
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -529,7 +529,7 @@ static int policy_vma(struct vm_area_struct *vma, struct mempolicy *new)
        if (!err) {
                mpol_get(new);
                vma->vm_policy = new;
-               mpol_free(old);
+               mpol_put(old);
        }
        return err;
 }
@@ -595,7 +595,7 @@ static long do_set_mempolicy(unsigned short mode, unsigned short flags,
        new = mpol_new(mode, flags, nodes);
        if (IS_ERR(new))
                return PTR_ERR(new);
-       mpol_free(current->mempolicy);
+       mpol_put(current->mempolicy);
        current->mempolicy = new;
        mpol_set_task_struct_flag();
        if (new && new->policy == MPOL_INTERLEAVE &&
@@ -948,7 +948,7 @@ static long do_mbind(unsigned long start, unsigned long len,
        }
 
        up_write(&mm->mmap_sem);
-       mpol_free(new);
+       mpol_put(new);
        return err;
 }
 
@@ -1446,14 +1446,14 @@ struct zonelist *huge_zonelist(struct vm_area_struct *vma, unsigned long addr,
                nid = interleave_nid(pol, vma, addr, HPAGE_SHIFT);
                if (unlikely(pol != &default_policy &&
                                pol != current->mempolicy))
-                       __mpol_free(pol);       /* finished with pol */
+                       __mpol_put(pol);        /* finished with pol */
                return node_zonelist(nid, gfp_flags);
        }
 
        zl = zonelist_policy(GFP_HIGHUSER, pol);
        if (unlikely(pol != &default_policy && pol != current->mempolicy)) {
                if (pol->policy != MPOL_BIND)
-                       __mpol_free(pol);       /* finished with pol */
+                       __mpol_put(pol);        /* finished with pol */
                else
                        *mpol = pol;    /* unref needed after allocation */
        }
@@ -1512,7 +1512,7 @@ alloc_page_vma(gfp_t gfp, struct vm_area_struct *vma, unsigned long addr)
                nid = interleave_nid(pol, vma, addr, PAGE_SHIFT);
                if (unlikely(pol != &default_policy &&
                                pol != current->mempolicy))
-                       __mpol_free(pol);       /* finished with pol */
+                       __mpol_put(pol);        /* finished with pol */
                return alloc_page_interleave(gfp, 0, nid);
        }
        zl = zonelist_policy(gfp, pol);
@@ -1522,7 +1522,7 @@ alloc_page_vma(gfp_t gfp, struct vm_area_struct *vma, unsigned long addr)
                 */
                struct page *page =  __alloc_pages_nodemask(gfp, 0,
                                                zl, nodemask_policy(gfp, pol));
-               __mpol_free(pol);
+               __mpol_put(pol);
                return page;
        }
        /*
@@ -1624,7 +1624,7 @@ int __mpol_equal(struct mempolicy *a, struct mempolicy *b)
 }
 
 /* Slow path of a mpol destructor. */
-void __mpol_free(struct mempolicy *p)
+void __mpol_put(struct mempolicy *p)
 {
        if (!atomic_dec_and_test(&p->refcnt))
                return;
@@ -1720,7 +1720,7 @@ static void sp_delete(struct shared_policy *sp, struct sp_node *n)
 {
        pr_debug("deleting %lx-l%lx\n", n->start, n->end);
        rb_erase(&n->nd, &sp->root);
-       mpol_free(n->policy);
+       mpol_put(n->policy);
        kmem_cache_free(sn_cache, n);
 }
 
@@ -1780,7 +1780,7 @@ restart:
                sp_insert(sp, new);
        spin_unlock(&sp->lock);
        if (new2) {
-               mpol_free(new2->policy);
+               mpol_put(new2->policy);
                kmem_cache_free(sn_cache, new2);
        }
        return 0;
@@ -1805,7 +1805,7 @@ void mpol_shared_policy_init(struct shared_policy *info, unsigned short policy,
                        /* Policy covers entire file */
                        pvma.vm_end = TASK_SIZE;
                        mpol_set_shared_policy(info, &pvma, newpol);
-                       mpol_free(newpol);
+                       mpol_put(newpol);
                }
        }
 }
@@ -1848,7 +1848,7 @@ void mpol_free_shared_policy(struct shared_policy *p)
                n = rb_entry(next, struct sp_node, nd);
                next = rb_next(&n->nd);
                rb_erase(&n->nd, &p->root);
-               mpol_free(n->policy);
+               mpol_put(n->policy);
                kmem_cache_free(sn_cache, n);
        }
        spin_unlock(&p->lock);
@@ -2068,7 +2068,7 @@ int show_numa_map(struct seq_file *m, void *v)
         * unref shared or other task's mempolicy
         */
        if (pol != &default_policy && pol != current->mempolicy)
-               __mpol_free(pol);
+               __mpol_put(pol);
 
        seq_printf(m, "%08lx %s", vma->vm_start, buffer);
 

diff --git a/mm/mmap.c b/mm/mmap.c
index 6aaf657..36c85e0 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -232,7 +232,7 @@ static struct vm_area_struct *remove_vma(struct vm_area_struct *vma)
                vma->vm_ops->close(vma);
        if (vma->vm_file)
                fput(vma->vm_file);
-       mpol_free(vma_policy(vma));
+       mpol_put(vma_policy(vma));
        kmem_cache_free(vm_area_cachep, vma);
        return next;
 }
@@ -626,7 +626,7 @@ again:                      remove_next = 1 + (end > next->vm_end);
                if (file)
                        fput(file);
                mm->map_count--;
-               mpol_free(vma_policy(next));
+               mpol_put(vma_policy(next));
                kmem_cache_free(vm_area_cachep, next);
                /*
                 * In mprotect's case 6 (see comments on vma_merge),
@@ -1182,7 +1182,7 @@ munmap_back:
 
        if (file && vma_merge(mm, prev, addr, vma->vm_end,
                        vma->vm_flags, NULL, file, pgoff, vma_policy(vma))) {
-               mpol_free(vma_policy(vma));
+               mpol_put(vma_policy(vma));
                kmem_cache_free(vm_area_cachep, vma);
                fput(file);
        } else {

diff --git a/mm/shmem.c b/mm/shmem.c
index 177c7a7..5326876 100644 (file)
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1196,7 +1196,7 @@ static struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp,
        pvma.vm_ops = NULL;
        pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx);
        page = swapin_readahead(entry, gfp, &pvma, 0);
-       mpol_free(pvma.vm_policy);
+       mpol_put(pvma.vm_policy);
        return page;
 }
 
@@ -1212,7 +1212,7 @@ static struct page *shmem_alloc_page(gfp_t gfp,
        pvma.vm_ops = NULL;
        pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx);
        page = alloc_page_vma(gfp, &pvma, 0);
-       mpol_free(pvma.vm_policy);
+       mpol_put(pvma.vm_policy);
        return page;
 }
 #else /* !CONFIG_NUMA */