[PATCH 16/17] ia64, mm: Convert ia64 to generic tlb

From: Peter Zijlstra
Date: Thu Feb 17 2011 - 12:11:44 EST


Cc: Tony Luck <tony.luck@xxxxxxxxx>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
---
arch/ia64/Kconfig | 1
arch/ia64/include/asm/tlb.h | 176 ++------------------------------------------
2 files changed, 9 insertions(+), 168 deletions(-)

Index: linux-2.6/arch/ia64/Kconfig
===================================================================
--- linux-2.6.orig/arch/ia64/Kconfig
+++ linux-2.6/arch/ia64/Kconfig
@@ -25,6 +25,7 @@ config IA64
select HAVE_GENERIC_HARDIRQS
select GENERIC_IRQ_PROBE
select GENERIC_PENDING_IRQ if SMP
+ select HAVE_MMU_GATHER_RANGE
select IRQ_PER_CPU
default y
help
Index: linux-2.6/arch/ia64/include/asm/tlb.h
===================================================================
--- linux-2.6.orig/arch/ia64/include/asm/tlb.h
+++ linux-2.6/arch/ia64/include/asm/tlb.h
@@ -46,30 +46,6 @@
#include <asm/tlbflush.h>
#include <asm/machvec.h>

-#ifdef CONFIG_SMP
-# define tlb_fast_mode(tlb) ((tlb)->nr == ~0U)
-#else
-# define tlb_fast_mode(tlb) (1)
-#endif
-
-/*
- * If we can't allocate a page to make a big batch of page pointers
- * to work on, then just handle a few from the on-stack structure.
- */
-#define IA64_GATHER_BUNDLE 8
-
-struct mmu_gather {
- struct mm_struct *mm;
- unsigned int nr; /* == ~0U => fast mode */
- unsigned int max;
- unsigned char fullmm; /* non-zero means full mm flush */
- unsigned char need_flush; /* really unmapped some PTEs? */
- unsigned long start_addr;
- unsigned long end_addr;
- struct page **pages;
- struct page *local[IA64_GATHER_BUNDLE];
-};
-
struct ia64_tr_entry {
u64 ifa;
u64 itir;
@@ -96,6 +72,12 @@ extern struct ia64_tr_entry *ia64_idtrs[
#define RR_RID_MASK 0x00000000ffffff00L
#define RR_TO_RID(val) ((val >> 8) & 0xffffff)

+static inline void tlb_flush(struct mmu_gather *tlb);
+
+#define tlb_migrate_finish(mm) platform_tlb_migrate_finish(mm)
+
+#include <asm-generic/tlb.h>
+
/*
* Flush the TLB for address range START to END and, if not in fast mode, release the
* freed pages that where gathered up to this point.
@@ -103,12 +85,6 @@ extern struct ia64_tr_entry *ia64_idtrs[
static inline void
ia64_tlb_flush_mmu (struct mmu_gather *tlb, unsigned long start, unsigned long end)
{
- unsigned int nr;
-
- if (!tlb->need_flush)
- return;
- tlb->need_flush = 0;
-
if (tlb->fullmm) {
/*
* Tearing down the entire address space. This happens both as a result
@@ -138,147 +114,11 @@ ia64_tlb_flush_mmu (struct mmu_gather *t
/* now flush the virt. page-table area mapping the address range: */
flush_tlb_range(&vma, ia64_thash(start), ia64_thash(end));
}
-
- /* lastly, release the freed pages */
- nr = tlb->nr;
- if (!tlb_fast_mode(tlb)) {
- unsigned long i;
- tlb->nr = 0;
- tlb->start_addr = ~0UL;
- for (i = 0; i < nr; ++i)
- free_page_and_swap_cache(tlb->pages[i]);
- }
-}
-
-static inline void __tlb_alloc_page(struct mmu_gather *tlb)
-{
- unsigned long addr = __get_free_pages(GFP_NOWAIT | __GFP_NOWARN, 0);
-
- if (addr) {
- tlb->pages = (void *)addr;
- tlb->max = PAGE_SIZE / sizeof(void *);
- }
-}
-
-
-static inline void
-tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned int full_mm_flush)
-{
- tlb->mm = mm;
- tlb->max = ARRAY_SIZE(tlb->local);
- tlb->pages = tlb->local;
- /*
- * Use fast mode if only 1 CPU is online.
- *
- * It would be tempting to turn on fast-mode for full_mm_flush as well. But this
- * doesn't work because of speculative accesses and software prefetching: the page
- * table of "mm" may (and usually is) the currently active page table and even
- * though the kernel won't do any user-space accesses during the TLB shoot down, a
- * compiler might use speculation or lfetch.fault on what happens to be a valid
- * user-space address. This in turn could trigger a TLB miss fault (or a VHPT
- * walk) and re-insert a TLB entry we just removed. Slow mode avoids such
- * problems. (We could make fast-mode work by switching the current task to a
- * different "mm" during the shootdown.) --davidm 08/02/2002
- */
- tlb->nr = (num_online_cpus() == 1) ? ~0U : 0;
- tlb->fullmm = full_mm_flush;
- tlb->start_addr = ~0UL;
-}
-
-/*
- * Called at the end of the shootdown operation to free up any resources that were
- * collected.
- */
-static inline void
-tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
-{
- /*
- * Note: tlb->nr may be 0 at this point, so we can't rely on tlb->start_addr and
- * tlb->end_addr.
- */
- ia64_tlb_flush_mmu(tlb, start, end);
-
- /* keep the page table cache within bounds */
- check_pgt_cache();
-
- if (tlb->pages != tlb->local)
- free_pages((unsigned long)tlb->pages, 0);
-}
-
-/*
- * Logically, this routine frees PAGE. On MP machines, the actual freeing of the page
- * must be delayed until after the TLB has been flushed (see comments at the beginning of
- * this file).
- */
-static inline int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
-{
- tlb->need_flush = 1;
-
- if (tlb_fast_mode(tlb)) {
- free_page_and_swap_cache(page);
- return 0;
- }
-
- if (!tlb->nr && tlb->pages == tlb->local)
- __tlb_alloc_page(tlb);
-
- tlb->pages[tlb->nr++] = page;
- if (tlb->nr >= tlb->max)
- return 1;
-
- return 0;
}

-static inline void tlb_flush_mmu(struct mmu_gather *tlb)
+static inline void tlb_flush(struct mmu_gather *tlb)
{
- ia64_tlb_flush_mmu(tlb, tlb->start_addr, tlb->end_addr);
+ ia64_tlb_flush_mmu(tlb, tlb->start, tlb->end);
}

-static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
-{
- if (__tlb_remove_page(tlb, page))
- tlb_flush_mmu(tlb);
-}
-
-/*
- * Remove TLB entry for PTE mapped at virtual address ADDRESS. This is called for any
- * PTE, not just those pointing to (normal) physical memory.
- */
-static inline void
-__tlb_remove_tlb_entry (struct mmu_gather *tlb, pte_t *ptep, unsigned long address)
-{
- if (tlb->start_addr == ~0UL)
- tlb->start_addr = address;
- tlb->end_addr = address + PAGE_SIZE;
-}
-
-#define tlb_migrate_finish(mm) platform_tlb_migrate_finish(mm)
-
-#define tlb_start_vma(tlb, vma) do { } while (0)
-#define tlb_end_vma(tlb, vma) do { } while (0)
-
-#define tlb_remove_tlb_entry(tlb, ptep, addr) \
-do { \
- tlb->need_flush = 1; \
- __tlb_remove_tlb_entry(tlb, ptep, addr); \
-} while (0)
-
-#define pte_free_tlb(tlb, ptep, address) \
-do { \
- tlb->need_flush = 1; \
- __pte_free_tlb(tlb, ptep, address); \
-} while (0)
-
-#define pmd_free_tlb(tlb, ptep, address) \
-do { \
- tlb->need_flush = 1; \
- __pmd_free_tlb(tlb, ptep, address); \
-} while (0)
-
-#define pud_free_tlb(tlb, pudp, address) \
-do { \
- tlb->need_flush = 1; \
- __pud_free_tlb(tlb, pudp, address); \
-} while (0)
-
#endif /* _ASM_IA64_TLB_H */


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