cpumask: update irq_desc to use cpumask_var_t

Impact: reduce memory usage, use new cpumask API.

Replace the affinity and pending_masks with cpumask_var_t's.  This adds
to the significant size reduction done with the SPARSE_IRQS changes.

The added functions (init_alloc_desc_masks & init_copy_desc_masks) are
in the include file so they can be inlined (and optimized out for the
!CONFIG_CPUMASKS_OFFSTACK case.)  [Naming chosen to be consistent with
the other init*irq functions, as well as the backwards arg declaration
of "from, to" instead of the more common "to, from" standard.]

Includes a slight change to the declaration of struct irq_desc to embed
the pending_mask within ifdef(CONFIG_SMP) to be consistent with other
references, and some small changes to Xen.

Tested: sparse/non-sparse/cpumask_offstack/non-cpumask_offstack/nonuma/nosmp on x86_64

Signed-off-by: Mike Travis <travis@sgi.com>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: virtualization@lists.osdl.org
Cc: xen-devel@lists.xensource.com
Cc: Yinghai Lu <yhlu.kernel@gmail.com>

1 files changed, 78 insertions, 3 deletions

diff --git a/include/linux/irq.h b/include/linux/irq.h
index f899b502f186..fa27210f1dfd 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -182,11 +182,11 @@ struct irq_desc {
         unsigned int            irqs_unhandled;
         spinlock_t              lock;
 #ifdef CONFIG_SMP
-        cpumask_t               affinity;
+        cpumask_var_t           affinity;
         unsigned int            cpu;
-#endif
 #ifdef CONFIG_GENERIC_PENDING_IRQ
-        cpumask_t               pending_mask;
+        cpumask_var_t           pending_mask;
+#endif
 #endif
 #ifdef CONFIG_PROC_FS
         struct proc_dir_entry   *dir;
@@ -422,4 +422,79 @@ extern int set_irq_msi(unsigned int irq, struct msi_desc *entry);
 
 #endif /* !CONFIG_S390 */
 
+#ifdef CONFIG_SMP
+/**
+ * init_alloc_desc_masks - allocate cpumasks for irq_desc
+ * @desc:       pointer to irq_desc struct
+ * @boot:       true if need bootmem
+ *
+ * Allocates affinity and pending_mask cpumask if required.
+ * Returns true if successful (or not required).
+ * Side effect: affinity has all bits set, pending_mask has all bits clear.
+ */
+static inline bool init_alloc_desc_masks(struct irq_desc *desc, int node,
+                                                                bool boot)
+{
+        if (boot) {
+                alloc_bootmem_cpumask_var(&desc->affinity);
+                cpumask_setall(desc->affinity);
+
+#ifdef CONFIG_GENERIC_PENDING_IRQ
+                alloc_bootmem_cpumask_var(&desc->pending_mask);
+                cpumask_clear(desc->pending_mask);
+#endif
+                return true;
+        }
+
+        if (!alloc_cpumask_var_node(&desc->affinity, GFP_ATOMIC, node))
+                return false;
+        cpumask_setall(desc->affinity);
+
+#ifdef CONFIG_GENERIC_PENDING_IRQ
+        if (!alloc_cpumask_var_node(&desc->pending_mask, GFP_ATOMIC, node)) {
+                free_cpumask_var(desc->affinity);
+                return false;
+        }
+        cpumask_clear(desc->pending_mask);
+#endif
+        return true;
+}
+
+/**
+ * init_copy_desc_masks - copy cpumasks for irq_desc
+ * @old_desc:   pointer to old irq_desc struct
+ * @new_desc:   pointer to new irq_desc struct
+ *
+ * Insures affinity and pending_masks are copied to new irq_desc.
+ * If !CONFIG_CPUMASKS_OFFSTACK the cpumasks are embedded in the
+ * irq_desc struct so the copy is redundant.
+ */
+
+static inline void init_copy_desc_masks(struct irq_desc *old_desc,
+                                        struct irq_desc *new_desc)
+{
+#ifdef CONFIG_CPUMASKS_OFFSTACK
+        cpumask_copy(new_desc->affinity, old_desc->affinity);
+
+#ifdef CONFIG_GENERIC_PENDING_IRQ
+        cpumask_copy(new_desc->pending_mask, old_desc->pending_mask);
+#endif
+#endif
+}
+
+#else /* !CONFIG_SMP */
+
+static inline bool init_alloc_desc_masks(struct irq_desc *desc, int node,
+                                                                bool boot)
+{
+        return true;
+}
+
+static inline void init_copy_desc_masks(struct irq_desc *old_desc,
+                                        struct irq_desc *new_desc)
+{
+}
+
+#endif  /* CONFIG_SMP */
+
 #endif /* _LINUX_IRQ_H */