On Mon 05-12-22 00:14:29, Zhongkun He wrote:
[...]
+/* Obtain a reference on the specified mpol */
static inline void mpol_get(struct mempolicy *pol)
{
if (pol)
Shouldn't this be mpol_needs_cond_ref?
- atomic_inc(&pol->refcnt);
+ percpu_ref_get(&pol->refcnt);
+}
+
+static inline bool mpol_tryget(struct mempolicy *pol)
+{
+ return pol && percpu_ref_tryget(&pol->refcnt);
}
+/*
+ * This function initiates destruction of mempolicy.
This is not a useful comment. It would be much more helpful to say when
this should be called.
+ */
+static inline void mpol_kill(struct mempolicy *pol)
+{
+ if (pol)
+ percpu_ref_kill(&pol->refcnt);
+}
+
+
extern bool __mpol_equal(struct mempolicy *a, struct mempolicy *b);
static inline bool mpol_equal(struct mempolicy *a, struct mempolicy *b)
{
@@ -197,11 +210,15 @@ static inline void mpol_put(struct mempolicy *p)
{
}
-static inline void mpol_cond_put(struct mempolicy *pol)
+static inline void mpol_get(struct mempolicy *pol)
{
}
-static inline void mpol_get(struct mempolicy *pol)
+static inline bool mpol_tryget(struct mempolicy *pol)
+{
+}
This should return false, right?
[...]
+/* Obtain a reference on the specified task mempolicy */
Again, this is pretty much clear from the name. It would be more useful
to explain how the pointer can be used - e.g. needs to call mpol_put
or mpol_kill depending on the calling context.
+static mempolicy *get_task_mpol(struct task_struct *p)
+{
+ struct mempolicy *pol;
+
+ rcu_read_lock();
+ pol = rcu_dereference(p->mempolicy);
+
+ if (!pol || mpol_tryget(pol))
Shouldn't be !mpol_tryget?
+ pol = NULL;
+ rcu_read_unlock();
+
+ return pol;
+}
+
I do not see any rcu_assign_pointer for the newly created policy so this
seems incomplete. Ditto no mpol_kill calls. I am unlikely to get into
follow up patches now. Please split up the work so that it is reviewable
more easily and then I can have a further look.
Thanks!
Thanks for your review, some changes may be in other patch,i will
reorganize the patches according to the suggestions to make
things clear.
Thanks.
