* Copyright 2001 Red Hat, Inc.
* Based on code from mm/memory.c Copyright Linus Torvalds and others.
*
+ * Copyright 2011 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
+ *
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* and page free order so much..
*/
#ifdef CONFIG_SMP
- #ifdef ARCH_FREE_PTR_NR
- #define FREE_PTR_NR ARCH_FREE_PTR_NR
- #else
- #define FREE_PTE_NR 506
- #endif
#define tlb_fast_mode(tlb) ((tlb)->nr == ~0U)
#else
- #define FREE_PTE_NR 1
#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 MMU_GATHER_BUNDLE 8
+
/* 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.
*/
struct mmu_gather {
struct mm_struct *mm;
unsigned int nr; /* set to ~0U means fast mode */
+ unsigned int max; /* nr < max */
unsigned int need_flush;/* Really unmapped some ptes? */
unsigned int fullmm; /* non-zero means full mm flush */
- struct page * pages[FREE_PTE_NR];
+#ifdef HAVE_ARCH_MMU_GATHER
+ struct arch_mmu_gather arch;
+#endif
+ struct page **pages;
+ struct page *local[MMU_GATHER_BUNDLE];
};
-/* Users of the generic TLB shootdown code must declare this storage space. */
-DECLARE_PER_CPU(struct mmu_gather, mmu_gathers);
+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(struct page *);
+ }
+}
/* tlb_gather_mmu
- * Return a pointer to an initialized struct mmu_gather.
+ * Called to initialize an (on-stack) mmu_gather structure for page-table
+ * tear-down from @mm. The @fullmm argument is used when @mm is without
+ * users and we're going to destroy the full address space (exit/execve).
*/
-static inline struct mmu_gather *
-tlb_gather_mmu(struct mm_struct *mm, unsigned int full_mm_flush)
+static inline void
+tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, bool fullmm)
{
- struct mmu_gather *tlb = &get_cpu_var(mmu_gathers);
-
tlb->mm = mm;
- /* Use fast mode if only one CPU is online */
- tlb->nr = num_online_cpus() > 1 ? 0U : ~0U;
+ tlb->max = ARRAY_SIZE(tlb->local);
+ tlb->pages = tlb->local;
+
+ if (num_online_cpus() > 1) {
+ tlb->nr = 0;
+ __tlb_alloc_page(tlb);
+ } else /* Use fast mode if only one CPU is online */
+ tlb->nr = ~0U;
- tlb->fullmm = full_mm_flush;
+ tlb->fullmm = fullmm;
- return tlb;
+#ifdef HAVE_ARCH_MMU_GATHER
+ tlb->arch = ARCH_MMU_GATHER_INIT;
+#endif
}
static inline void
-tlb_flush_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
+tlb_flush_mmu(struct mmu_gather *tlb)
{
if (!tlb->need_flush)
return;
if (!tlb_fast_mode(tlb)) {
free_pages_and_swap_cache(tlb->pages, tlb->nr);
tlb->nr = 0;
+ /*
+ * If we are using the local on-stack array of pages for MMU
+ * gather, try allocating an off-stack array again as we have
+ * recently freed pages.
+ */
+ if (tlb->pages == tlb->local)
+ __tlb_alloc_page(tlb);
}
}
static inline void
tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
{
- tlb_flush_mmu(tlb, start, end);
+ tlb_flush_mmu(tlb);
/* keep the page table cache within bounds */
check_pgt_cache();
- put_cpu_var(mmu_gathers);
+ if (tlb->pages != tlb->local)
+ free_pages((unsigned long)tlb->pages, 0);
}
-/* tlb_remove_page
+/* __tlb_remove_page
* Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)), while
* handling the additional races in SMP caused by other CPUs caching valid
- * mappings in their TLBs.
+ * mappings in their TLBs. Returns the number of free page slots left.
+ * When out of page slots we must call tlb_flush_mmu().
*/
-static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
+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;
+ return 1; /* avoid calling tlb_flush_mmu() */
}
tlb->pages[tlb->nr++] = page;
- if (tlb->nr >= FREE_PTE_NR)
- tlb_flush_mmu(tlb, 0, 0);
+ VM_BUG_ON(tlb->nr > tlb->max);
+
+ return tlb->max - tlb->nr;
+}
+
+/* tlb_remove_page
+ * Similar to __tlb_remove_page but will call tlb_flush_mmu() itself when
+ * required.
+ */
+static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
+{
+ if (!__tlb_remove_page(tlb, page))
+ tlb_flush_mmu(tlb);
}
/**
git.openpandora.org / pandora-kernel.git / blobdiff