Commit 15a23ffa authored by Hugh Dickins's avatar Hugh Dickins Committed by Linus Torvalds

[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: default avatarHugh Dickins <hugh@veritas.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 7be7a546
......@@ -39,8 +39,7 @@ DECLARE_PER_CPU(struct mmu_gather, mmu_gathers);
static inline struct mmu_gather *
tlb_gather_mmu(struct mm_struct *mm, unsigned int full_mm_flush)
{
int cpu = smp_processor_id();
struct mmu_gather *tlb = &per_cpu(mmu_gathers, cpu);
struct mmu_gather *tlb = &get_cpu_var(mmu_gathers);
tlb->mm = mm;
tlb->freed = 0;
......@@ -65,6 +64,8 @@ tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
/* keep the page table cache within bounds */
check_pgt_cache();
put_cpu_var(mmu_gathers);
}
static inline unsigned int tlb_is_full_mm(struct mmu_gather *tlb)
......
......@@ -17,13 +17,12 @@ struct mmu_gather {
unsigned int avoided_flushes;
};
extern struct mmu_gather mmu_gathers[NR_CPUS];
DECLARE_PER_CPU(struct mmu_gather, mmu_gathers);
static inline struct mmu_gather *
tlb_gather_mmu(struct mm_struct *mm, unsigned int full_mm_flush)
{
int cpu = smp_processor_id();
struct mmu_gather *tlb = &mmu_gathers[cpu];
struct mmu_gather *tlb = &get_cpu_var(mmu_gathers);
tlb->mm = mm;
tlb->freed = 0;
......@@ -52,6 +51,8 @@ tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
/* keep the page table cache within bounds */
check_pgt_cache();
put_cpu_var(mmu_gathers);
}
......
......@@ -35,9 +35,7 @@
#endif
/* struct mmu_gather is an opaque type used by the mm code for passing around
* any data needed by arch specific code for tlb_remove_page. This structure
* can be per-CPU or per-MM as the page table lock is held for the duration of
* TLB shootdown.
* any data needed by arch specific code for tlb_remove_page.
*/
struct mmu_gather {
struct mm_struct *mm;
......@@ -57,7 +55,7 @@ DECLARE_PER_CPU(struct mmu_gather, mmu_gathers);
static inline struct mmu_gather *
tlb_gather_mmu(struct mm_struct *mm, unsigned int full_mm_flush)
{
struct mmu_gather *tlb = &per_cpu(mmu_gathers, smp_processor_id());
struct mmu_gather *tlb = &get_cpu_var(mmu_gathers);
tlb->mm = mm;
......@@ -85,7 +83,7 @@ tlb_flush_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
/* tlb_finish_mmu
* Called at the end of the shootdown operation to free up any resources
* that were required. The page table lock is still held at this point.
* that were required.
*/
static inline void
tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
......@@ -101,6 +99,8 @@ tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
/* keep the page table cache within bounds */
check_pgt_cache();
put_cpu_var(mmu_gathers);
}
static inline unsigned int
......
......@@ -129,7 +129,7 @@ ia64_tlb_flush_mmu (struct mmu_gather *tlb, unsigned long start, unsigned long e
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 @@ tlb_gather_mmu (struct mm_struct *mm, unsigned int full_mm_flush)
/*
* 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 @@ tlb_finish_mmu (struct mmu_gather *tlb, unsigned long start, unsigned long end)
/* keep the page table cache within bounds */
check_pgt_cache();
put_cpu_var(mmu_gathers);
}
static inline unsigned int
......
......@@ -44,7 +44,7 @@ extern void flush_tlb_pending(void);
static inline struct mmu_gather *tlb_gather_mmu(struct mm_struct *mm, unsigned int full_mm_flush)
{
struct mmu_gather *mp = &__get_cpu_var(mmu_gathers);
struct mmu_gather *mp = &get_cpu_var(mmu_gathers);
BUG_ON(mp->tlb_nr);
......@@ -97,6 +97,8 @@ static inline void tlb_finish_mmu(struct mmu_gather *mp, unsigned long start, un
/* keep the page table cache within bounds */
check_pgt_cache();
put_cpu_var(mmu_gathers);
}
static inline unsigned int tlb_is_full_mm(struct mmu_gather *mp)
......
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