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authorBenjamin Herrenschmidt <benh@kernel.crashing.org>2009-07-23 23:15:28 (GMT)
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2009-08-20 00:24:56 (GMT)
commitc7cc58a1ad8dfe3c199d3b6ce50412b86dd3edaf (patch)
tree1d1ded72de81743ddd1306677d64757136972402 /arch
parentcf54dc7cd4f9aab55cd3e1794b0b74c3c88cd1a0 (diff)
downloadlinux-fsl-qoriq-c7cc58a1ad8dfe3c199d3b6ce50412b86dd3edaf.tar.xz
powerpc/mm: Rework & cleanup page table freeing code path
That patch used to just add a hook to page table flushing but pulling that string brought out a whole bunch of issues, so it now does that and more: - We now make the RCU batching of page freeing SMP only, as I believe it was intended initially. We make a few more things compile to nothing on !CONFIG_SMP - Some macros are turned into functions, though that forced me to out of line a few stuffs due to unsolvable include depenencies, however it's probably better that way anyway, it's not -that- critical code path. - 32-bit didn't call pte_free_finish() on tlb_flush() which means that it wouldn't push out the batch to RCU for delayed freeing when a bunch of page tables have been freed, they would just stay in there until the batch gets full. 64-bit BookE will use that hook to maintain the virtually linear page tables or the indirect entries in the TLB when using the HW loader. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/include/asm/pgalloc.h39
-rw-r--r--arch/powerpc/include/asm/tlb.h38
-rw-r--r--arch/powerpc/mm/pgtable.c10
-rw-r--r--arch/powerpc/mm/tlb_hash32.c3
-rw-r--r--arch/powerpc/mm/tlb_hash64.c15
-rw-r--r--arch/powerpc/mm/tlb_nohash.c8
6 files changed, 67 insertions, 46 deletions
diff --git a/arch/powerpc/include/asm/pgalloc.h b/arch/powerpc/include/asm/pgalloc.h
index 1730e5e..34b0806 100644
--- a/arch/powerpc/include/asm/pgalloc.h
+++ b/arch/powerpc/include/asm/pgalloc.h
@@ -4,6 +4,15 @@
#include <linux/mm.h>
+#ifdef CONFIG_PPC_BOOK3E
+extern void tlb_flush_pgtable(struct mmu_gather *tlb, unsigned long address);
+#else /* CONFIG_PPC_BOOK3E */
+static inline void tlb_flush_pgtable(struct mmu_gather *tlb,
+ unsigned long address)
+{
+}
+#endif /* !CONFIG_PPC_BOOK3E */
+
static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
{
free_page((unsigned long)pte);
@@ -35,19 +44,27 @@ static inline pgtable_free_t pgtable_free_cache(void *p, int cachenum,
#include <asm/pgalloc-32.h>
#endif
-extern void pgtable_free_tlb(struct mmu_gather *tlb, pgtable_free_t pgf);
-
#ifdef CONFIG_SMP
-#define __pte_free_tlb(tlb,ptepage,address) \
-do { \
- pgtable_page_dtor(ptepage); \
- pgtable_free_tlb(tlb, pgtable_free_cache(page_address(ptepage), \
- PTE_NONCACHE_NUM, PTE_TABLE_SIZE-1)); \
-} while (0)
-#else
-#define __pte_free_tlb(tlb, pte, address) pte_free((tlb)->mm, (pte))
-#endif
+extern void pgtable_free_tlb(struct mmu_gather *tlb, pgtable_free_t pgf);
+extern void pte_free_finish(void);
+#else /* CONFIG_SMP */
+static inline void pgtable_free_tlb(struct mmu_gather *tlb, pgtable_free_t pgf)
+{
+ pgtable_free(pgf);
+}
+static inline void pte_free_finish(void) { }
+#endif /* !CONFIG_SMP */
+static inline void __pte_free_tlb(struct mmu_gather *tlb, struct page *ptepage,
+ unsigned long address)
+{
+ pgtable_free_t pgf = pgtable_free_cache(page_address(ptepage),
+ PTE_NONCACHE_NUM,
+ PTE_TABLE_SIZE-1);
+ tlb_flush_pgtable(tlb, address);
+ pgtable_page_dtor(ptepage);
+ pgtable_free_tlb(tlb, pgf);
+}
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_PGALLOC_H */
diff --git a/arch/powerpc/include/asm/tlb.h b/arch/powerpc/include/asm/tlb.h
index e20ff75..e2b428b 100644
--- a/arch/powerpc/include/asm/tlb.h
+++ b/arch/powerpc/include/asm/tlb.h
@@ -25,57 +25,25 @@
#include <linux/pagemap.h>
-struct mmu_gather;
-
#define tlb_start_vma(tlb, vma) do { } while (0)
#define tlb_end_vma(tlb, vma) do { } while (0)
-#if !defined(CONFIG_PPC_STD_MMU)
-
-#define tlb_flush(tlb) flush_tlb_mm((tlb)->mm)
-
-#elif defined(__powerpc64__)
-
-extern void pte_free_finish(void);
-
-static inline void tlb_flush(struct mmu_gather *tlb)
-{
- struct ppc64_tlb_batch *tlbbatch = &__get_cpu_var(ppc64_tlb_batch);
-
- /* If there's a TLB batch pending, then we must flush it because the
- * pages are going to be freed and we really don't want to have a CPU
- * access a freed page because it has a stale TLB
- */
- if (tlbbatch->index)
- __flush_tlb_pending(tlbbatch);
-
- pte_free_finish();
-}
-
-#else
-
extern void tlb_flush(struct mmu_gather *tlb);
-#endif
-
/* Get the generic bits... */
#include <asm-generic/tlb.h>
-#if !defined(CONFIG_PPC_STD_MMU) || defined(__powerpc64__)
-
-#define __tlb_remove_tlb_entry(tlb, pte, address) do { } while (0)
-
-#else
extern void flush_hash_entry(struct mm_struct *mm, pte_t *ptep,
unsigned long address);
static inline void __tlb_remove_tlb_entry(struct mmu_gather *tlb, pte_t *ptep,
- unsigned long address)
+ unsigned long address)
{
+#ifdef CONFIG_PPC_STD_MMU_32
if (pte_val(*ptep) & _PAGE_HASHPTE)
flush_hash_entry(tlb->mm, ptep, address);
+#endif
}
-#endif
#endif /* __KERNEL__ */
#endif /* __ASM_POWERPC_TLB_H */
diff --git a/arch/powerpc/mm/pgtable.c b/arch/powerpc/mm/pgtable.c
index 627767d..a65979a 100644
--- a/arch/powerpc/mm/pgtable.c
+++ b/arch/powerpc/mm/pgtable.c
@@ -30,6 +30,14 @@
#include <asm/tlbflush.h>
#include <asm/tlb.h>
+#ifdef CONFIG_SMP
+
+/*
+ * Handle batching of page table freeing on SMP. Page tables are
+ * queued up and send to be freed later by RCU in order to avoid
+ * freeing a page table page that is being walked without locks
+ */
+
static DEFINE_PER_CPU(struct pte_freelist_batch *, pte_freelist_cur);
static unsigned long pte_freelist_forced_free;
@@ -116,6 +124,8 @@ void pte_free_finish(void)
*batchp = NULL;
}
+#endif /* CONFIG_SMP */
+
/*
* Handle i/d cache flushing, called from set_pte_at() or ptep_set_access_flags()
*/
diff --git a/arch/powerpc/mm/tlb_hash32.c b/arch/powerpc/mm/tlb_hash32.c
index 6519058..8aaa8b7 100644
--- a/arch/powerpc/mm/tlb_hash32.c
+++ b/arch/powerpc/mm/tlb_hash32.c
@@ -71,6 +71,9 @@ void tlb_flush(struct mmu_gather *tlb)
*/
_tlbia();
}
+
+ /* Push out batch of freed page tables */
+ pte_free_finish();
}
/*
diff --git a/arch/powerpc/mm/tlb_hash64.c b/arch/powerpc/mm/tlb_hash64.c
index 937eb90..8e35a60 100644
--- a/arch/powerpc/mm/tlb_hash64.c
+++ b/arch/powerpc/mm/tlb_hash64.c
@@ -154,6 +154,21 @@ void __flush_tlb_pending(struct ppc64_tlb_batch *batch)
batch->index = 0;
}
+void tlb_flush(struct mmu_gather *tlb)
+{
+ struct ppc64_tlb_batch *tlbbatch = &__get_cpu_var(ppc64_tlb_batch);
+
+ /* If there's a TLB batch pending, then we must flush it because the
+ * pages are going to be freed and we really don't want to have a CPU
+ * access a freed page because it has a stale TLB
+ */
+ if (tlbbatch->index)
+ __flush_tlb_pending(tlbbatch);
+
+ /* Push out batch of freed page tables */
+ pte_free_finish();
+}
+
/**
* __flush_hash_table_range - Flush all HPTEs for a given address range
* from the hash table (and the TLB). But keeps
diff --git a/arch/powerpc/mm/tlb_nohash.c b/arch/powerpc/mm/tlb_nohash.c
index 761e888..6b43fc4 100644
--- a/arch/powerpc/mm/tlb_nohash.c
+++ b/arch/powerpc/mm/tlb_nohash.c
@@ -233,3 +233,11 @@ void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
flush_tlb_mm(vma->vm_mm);
}
EXPORT_SYMBOL(flush_tlb_range);
+
+void tlb_flush(struct mmu_gather *tlb)
+{
+ flush_tlb_mm(tlb->mm);
+
+ /* Push out batch of freed page tables */
+ pte_free_finish();
+}