Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...

[linux] / kernel / fork.c

diff --git a/kernel/fork.c b/kernel/fork.c
index 1b27bab..9d8d0e0 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -2276,6 +2276,8 @@ static void sighand_ctor(void *data)
 
 void __init proc_caches_init(void)
 {
+       unsigned int mm_size;
+
        sighand_cachep = kmem_cache_create("sighand_cache",
                        sizeof(struct sighand_struct), 0,
                        SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_TYPESAFE_BY_RCU|
@@ -2292,15 +2294,16 @@ void __init proc_caches_init(void)
                        sizeof(struct fs_struct), 0,
                        SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT,
                        NULL);
+
        /*
-        * FIXME! The "sizeof(struct mm_struct)" currently includes the
-        * whole struct cpumask for the OFFSTACK case. We could change
-        * this to *only* allocate as much of it as required by the
-        * maximum number of CPU's we can ever have.  The cpumask_allocation
-        * is at the end of the structure, exactly for that reason.
+        * The mm_cpumask is located at the end of mm_struct, and is
+        * dynamically sized based on the maximum CPU number this system
+        * can have, taking hotplug into account (nr_cpu_ids).
         */
+       mm_size = sizeof(struct mm_struct) + cpumask_size();
+
        mm_cachep = kmem_cache_create_usercopy("mm_struct",
-                       sizeof(struct mm_struct), ARCH_MIN_MMSTRUCT_ALIGN,
+                       mm_size, ARCH_MIN_MMSTRUCT_ALIGN,
                        SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT,
                        offsetof(struct mm_struct, saved_auxv),
                        sizeof_field(struct mm_struct, saved_auxv),