Commit de03c72c authored by KOSAKI Motohiro's avatar KOSAKI Motohiro Committed by Linus Torvalds
Browse files

mm: convert mm->cpu_vm_cpumask into cpumask_var_t



cpumask_t is very big struct and cpu_vm_mask is placed wrong position.
It might lead to reduce cache hit ratio.

This patch has two change.
1) Move the place of cpumask into last of mm_struct. Because usually cpumask
   is accessed only front bits when the system has cpu-hotplug capability
2) Convert cpu_vm_mask into cpumask_var_t. It may help to reduce memory
   footprint if cpumask_size() will use nr_cpumask_bits properly in future.

In addition, this patch change the name of cpu_vm_mask with cpu_vm_mask_var.
It may help to detect out of tree cpu_vm_mask users.

This patch has no functional change.

[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 692e0b35
......@@ -16,7 +16,7 @@ on all processors in the system. Don't let this scare you into
thinking SMP cache/tlb flushing must be so inefficient, this is in
fact an area where many optimizations are possible. For example,
if it can be proven that a user address space has never executed
on a cpu (see vma->cpu_vm_mask), one need not perform a flush
on a cpu (see mm_cpumask()), one need not perform a flush
for this address space on that cpu.
First, the TLB flushing interfaces, since they are the simplest. The
......
......@@ -110,7 +110,6 @@ static struct mm_struct tboot_mm = {
.mmap_sem = __RWSEM_INITIALIZER(init_mm.mmap_sem),
.page_table_lock = __SPIN_LOCK_UNLOCKED(init_mm.page_table_lock),
.mmlist = LIST_HEAD_INIT(init_mm.mmlist),
.cpu_vm_mask = CPU_MASK_ALL,
};
static inline void switch_to_tboot_pt(void)
......
......@@ -265,8 +265,6 @@ struct mm_struct {
struct linux_binfmt *binfmt;
cpumask_t cpu_vm_mask;
/* Architecture-specific MM context */
mm_context_t context;
......@@ -316,9 +314,14 @@ struct mm_struct {
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
pgtable_t pmd_huge_pte; /* protected by page_table_lock */
#endif
cpumask_var_t cpu_vm_mask_var;
};
/* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
#define mm_cpumask(mm) (&(mm)->cpu_vm_mask)
static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
{
return mm->cpu_vm_mask_var;
}
#endif /* _LINUX_MM_TYPES_H */
......@@ -2176,6 +2176,7 @@ static inline void mmdrop(struct mm_struct * mm)
if (unlikely(atomic_dec_and_test(&mm->mm_count)))
__mmdrop(mm);
}
extern int mm_init_cpumask(struct mm_struct *mm, struct mm_struct *oldmm);
/* mmput gets rid of the mappings and all user-space */
extern void mmput(struct mm_struct *);
......
......@@ -509,6 +509,8 @@ asmlinkage void __init start_kernel(void)
sort_main_extable();
trap_init();
mm_init();
BUG_ON(mm_init_cpumask(&init_mm, 0));
/*
* Set up the scheduler prior starting any interrupts (such as the
* timer interrupt). Full topology setup happens at smp_init()
......
......@@ -485,6 +485,20 @@ static void mm_init_aio(struct mm_struct *mm)
#endif
}
int mm_init_cpumask(struct mm_struct *mm, struct mm_struct *oldmm)
{
#ifdef CONFIG_CPUMASK_OFFSTACK
if (!alloc_cpumask_var(&mm->cpu_vm_mask_var, GFP_KERNEL))
return -ENOMEM;
if (oldmm)
cpumask_copy(mm_cpumask(mm), mm_cpumask(oldmm));
else
memset(mm_cpumask(mm), 0, cpumask_size());
#endif
return 0;
}
static struct mm_struct * mm_init(struct mm_struct * mm, struct task_struct *p)
{
atomic_set(&mm->mm_users, 1);
......@@ -521,10 +535,20 @@ struct mm_struct * mm_alloc(void)
struct mm_struct * mm;
mm = allocate_mm();
if (mm) {
memset(mm, 0, sizeof(*mm));
mm = mm_init(mm, current);
if (!mm)
return NULL;
memset(mm, 0, sizeof(*mm));
mm = mm_init(mm, current);
if (!mm)
return NULL;
if (mm_init_cpumask(mm, NULL)) {
mm_free_pgd(mm);
free_mm(mm);
return NULL;
}
return mm;
}
......@@ -536,6 +560,7 @@ struct mm_struct * mm_alloc(void)
void __mmdrop(struct mm_struct *mm)
{
BUG_ON(mm == &init_mm);
free_cpumask_var(mm->cpu_vm_mask_var);
mm_free_pgd(mm);
destroy_context(mm);
mmu_notifier_mm_destroy(mm);
......@@ -690,6 +715,9 @@ struct mm_struct *dup_mm(struct task_struct *tsk)
if (!mm_init(mm, tsk))
goto fail_nomem;
if (mm_init_cpumask(mm, oldmm))
goto fail_nocpumask;
if (init_new_context(tsk, mm))
goto fail_nocontext;
......@@ -716,6 +744,9 @@ fail_nomem:
return NULL;
fail_nocontext:
free_cpumask_var(mm->cpu_vm_mask_var);
fail_nocpumask:
/*
* If init_new_context() failed, we cannot use mmput() to free the mm
* because it calls destroy_context()
......
......@@ -21,6 +21,5 @@ struct mm_struct init_mm = {
.mmap_sem = __RWSEM_INITIALIZER(init_mm.mmap_sem),
.page_table_lock = __SPIN_LOCK_UNLOCKED(init_mm.page_table_lock),
.mmlist = LIST_HEAD_INIT(init_mm.mmlist),
.cpu_vm_mask = CPU_MASK_ALL,
INIT_MM_CONTEXT(init_mm)
};
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment