]>
Commit | Line | Data |
---|---|---|
0186f47e KG |
1 | /* |
2 | * This file contains common routines for dealing with free of page tables | |
3 | * | |
4 | * Derived from arch/powerpc/mm/tlb_64.c: | |
5 | * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) | |
6 | * | |
7 | * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au) | |
8 | * and Cort Dougan (PReP) (cort@cs.nmt.edu) | |
9 | * Copyright (C) 1996 Paul Mackerras | |
10 | * | |
11 | * Derived from "arch/i386/mm/init.c" | |
12 | * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds | |
13 | * | |
14 | * Dave Engebretsen <engebret@us.ibm.com> | |
15 | * Rework for PPC64 port. | |
16 | * | |
17 | * This program is free software; you can redistribute it and/or | |
18 | * modify it under the terms of the GNU General Public License | |
19 | * as published by the Free Software Foundation; either version | |
20 | * 2 of the License, or (at your option) any later version. | |
21 | */ | |
22 | ||
23 | #include <linux/kernel.h> | |
24 | #include <linux/mm.h> | |
25 | #include <linux/init.h> | |
26 | #include <linux/percpu.h> | |
27 | #include <linux/hardirq.h> | |
28 | #include <asm/pgalloc.h> | |
29 | #include <asm/tlbflush.h> | |
30 | #include <asm/tlb.h> | |
31 | ||
32 | static DEFINE_PER_CPU(struct pte_freelist_batch *, pte_freelist_cur); | |
33 | static unsigned long pte_freelist_forced_free; | |
34 | ||
35 | struct pte_freelist_batch | |
36 | { | |
37 | struct rcu_head rcu; | |
38 | unsigned int index; | |
39 | pgtable_free_t tables[0]; | |
40 | }; | |
41 | ||
42 | #define PTE_FREELIST_SIZE \ | |
43 | ((PAGE_SIZE - sizeof(struct pte_freelist_batch)) \ | |
44 | / sizeof(pgtable_free_t)) | |
45 | ||
46 | static void pte_free_smp_sync(void *arg) | |
47 | { | |
48 | /* Do nothing, just ensure we sync with all CPUs */ | |
49 | } | |
50 | ||
51 | /* This is only called when we are critically out of memory | |
52 | * (and fail to get a page in pte_free_tlb). | |
53 | */ | |
54 | static void pgtable_free_now(pgtable_free_t pgf) | |
55 | { | |
56 | pte_freelist_forced_free++; | |
57 | ||
58 | smp_call_function(pte_free_smp_sync, NULL, 1); | |
59 | ||
60 | pgtable_free(pgf); | |
61 | } | |
62 | ||
63 | static void pte_free_rcu_callback(struct rcu_head *head) | |
64 | { | |
65 | struct pte_freelist_batch *batch = | |
66 | container_of(head, struct pte_freelist_batch, rcu); | |
67 | unsigned int i; | |
68 | ||
69 | for (i = 0; i < batch->index; i++) | |
70 | pgtable_free(batch->tables[i]); | |
71 | ||
72 | free_page((unsigned long)batch); | |
73 | } | |
74 | ||
75 | static void pte_free_submit(struct pte_freelist_batch *batch) | |
76 | { | |
77 | INIT_RCU_HEAD(&batch->rcu); | |
78 | call_rcu(&batch->rcu, pte_free_rcu_callback); | |
79 | } | |
80 | ||
81 | void pgtable_free_tlb(struct mmu_gather *tlb, pgtable_free_t pgf) | |
82 | { | |
83 | /* This is safe since tlb_gather_mmu has disabled preemption */ | |
84 | cpumask_t local_cpumask = cpumask_of_cpu(smp_processor_id()); | |
85 | struct pte_freelist_batch **batchp = &__get_cpu_var(pte_freelist_cur); | |
86 | ||
87 | if (atomic_read(&tlb->mm->mm_users) < 2 || | |
88 | cpus_equal(tlb->mm->cpu_vm_mask, local_cpumask)) { | |
89 | pgtable_free(pgf); | |
90 | return; | |
91 | } | |
92 | ||
93 | if (*batchp == NULL) { | |
94 | *batchp = (struct pte_freelist_batch *)__get_free_page(GFP_ATOMIC); | |
95 | if (*batchp == NULL) { | |
96 | pgtable_free_now(pgf); | |
97 | return; | |
98 | } | |
99 | (*batchp)->index = 0; | |
100 | } | |
101 | (*batchp)->tables[(*batchp)->index++] = pgf; | |
102 | if ((*batchp)->index == PTE_FREELIST_SIZE) { | |
103 | pte_free_submit(*batchp); | |
104 | *batchp = NULL; | |
105 | } | |
106 | } | |
107 | ||
108 | void pte_free_finish(void) | |
109 | { | |
110 | /* This is safe since tlb_gather_mmu has disabled preemption */ | |
111 | struct pte_freelist_batch **batchp = &__get_cpu_var(pte_freelist_cur); | |
112 | ||
113 | if (*batchp == NULL) | |
114 | return; | |
115 | pte_free_submit(*batchp); | |
116 | *batchp = NULL; | |
117 | } |