[PATCH] mm: tlb_gather_mmu get_cpu_var
tlb_gather_mmu dates from before kernel preemption was allowed, and uses
smp_processor_id or __get_cpu_var to find its per-cpu mmu_gather. That works
because it's currently only called after getting page_table_lock, which is not
dropped until after the matching tlb_finish_mmu. But don't rely on that, it
will soon change: now disable preemption internally by proper get_cpu_var in
tlb_gather_mmu, put_cpu_var in tlb_finish_mmu.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/asm-ia64/tlb.h b/include/asm-ia64/tlb.h
index 3a9a6d1..1b82299 100644
--- a/include/asm-ia64/tlb.h
+++ b/include/asm-ia64/tlb.h
@@ -129,7 +129,7 @@
static inline struct mmu_gather *
tlb_gather_mmu (struct mm_struct *mm, unsigned int full_mm_flush)
{
- struct mmu_gather *tlb = &__get_cpu_var(mmu_gathers);
+ struct mmu_gather *tlb = &get_cpu_var(mmu_gathers);
tlb->mm = mm;
/*
@@ -154,7 +154,7 @@
/*
* Called at the end of the shootdown operation to free up any resources that were
- * collected. The page table lock is still held at this point.
+ * collected.
*/
static inline void
tlb_finish_mmu (struct mmu_gather *tlb, unsigned long start, unsigned long end)
@@ -174,6 +174,8 @@
/* keep the page table cache within bounds */
check_pgt_cache();
+
+ put_cpu_var(mmu_gathers);
}
static inline unsigned int