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Diffstat (limited to 'mm/ksm.c')
-rw-r--r--mm/ksm.c71
1 files changed, 23 insertions, 48 deletions
diff --git a/mm/ksm.c b/mm/ksm.c
index 6c3e99b4ae7c..e2ae00458320 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -33,6 +33,7 @@
#include <linux/mmu_notifier.h>
#include <linux/swap.h>
#include <linux/ksm.h>
+#include <linux/hash.h>
#include <asm/tlbflush.h>
#include "internal.h"
@@ -153,8 +154,9 @@ struct rmap_item {
static struct rb_root root_stable_tree = RB_ROOT;
static struct rb_root root_unstable_tree = RB_ROOT;
-#define MM_SLOTS_HASH_HEADS 1024
-static struct hlist_head *mm_slots_hash;
+#define MM_SLOTS_HASH_SHIFT 10
+#define MM_SLOTS_HASH_HEADS (1 << MM_SLOTS_HASH_SHIFT)
+static struct hlist_head mm_slots_hash[MM_SLOTS_HASH_HEADS];
static struct mm_slot ksm_mm_head = {
.mm_list = LIST_HEAD_INIT(ksm_mm_head.mm_list),
@@ -269,28 +271,13 @@ static inline void free_mm_slot(struct mm_slot *mm_slot)
kmem_cache_free(mm_slot_cache, mm_slot);
}
-static int __init mm_slots_hash_init(void)
-{
- mm_slots_hash = kzalloc(MM_SLOTS_HASH_HEADS * sizeof(struct hlist_head),
- GFP_KERNEL);
- if (!mm_slots_hash)
- return -ENOMEM;
- return 0;
-}
-
-static void __init mm_slots_hash_free(void)
-{
- kfree(mm_slots_hash);
-}
-
static struct mm_slot *get_mm_slot(struct mm_struct *mm)
{
struct mm_slot *mm_slot;
struct hlist_head *bucket;
struct hlist_node *node;
- bucket = &mm_slots_hash[((unsigned long)mm / sizeof(struct mm_struct))
- % MM_SLOTS_HASH_HEADS];
+ bucket = &mm_slots_hash[hash_ptr(mm, MM_SLOTS_HASH_SHIFT)];
hlist_for_each_entry(mm_slot, node, bucket, link) {
if (mm == mm_slot->mm)
return mm_slot;
@@ -303,8 +290,7 @@ static void insert_to_mm_slots_hash(struct mm_struct *mm,
{
struct hlist_head *bucket;
- bucket = &mm_slots_hash[((unsigned long)mm / sizeof(struct mm_struct))
- % MM_SLOTS_HASH_HEADS];
+ bucket = &mm_slots_hash[hash_ptr(mm, MM_SLOTS_HASH_SHIFT)];
mm_slot->mm = mm;
hlist_add_head(&mm_slot->link, bucket);
}
@@ -318,19 +304,14 @@ static void hold_anon_vma(struct rmap_item *rmap_item,
struct anon_vma *anon_vma)
{
rmap_item->anon_vma = anon_vma;
- atomic_inc(&anon_vma->external_refcount);
+ get_anon_vma(anon_vma);
}
-static void drop_anon_vma(struct rmap_item *rmap_item)
+static void ksm_drop_anon_vma(struct rmap_item *rmap_item)
{
struct anon_vma *anon_vma = rmap_item->anon_vma;
- if (atomic_dec_and_lock(&anon_vma->external_refcount, &anon_vma->lock)) {
- int empty = list_empty(&anon_vma->head);
- spin_unlock(&anon_vma->lock);
- if (empty)
- anon_vma_free(anon_vma);
- }
+ drop_anon_vma(anon_vma);
}
/*
@@ -415,7 +396,7 @@ static void break_cow(struct rmap_item *rmap_item)
* It is not an accident that whenever we want to break COW
* to undo, we also need to drop a reference to the anon_vma.
*/
- drop_anon_vma(rmap_item);
+ ksm_drop_anon_vma(rmap_item);
down_read(&mm->mmap_sem);
if (ksm_test_exit(mm))
@@ -470,7 +451,7 @@ static void remove_node_from_stable_tree(struct stable_node *stable_node)
ksm_pages_sharing--;
else
ksm_pages_shared--;
- drop_anon_vma(rmap_item);
+ ksm_drop_anon_vma(rmap_item);
rmap_item->address &= PAGE_MASK;
cond_resched();
}
@@ -558,7 +539,7 @@ static void remove_rmap_item_from_tree(struct rmap_item *rmap_item)
else
ksm_pages_shared--;
- drop_anon_vma(rmap_item);
+ ksm_drop_anon_vma(rmap_item);
rmap_item->address &= PAGE_MASK;
} else if (rmap_item->address & UNSTABLE_FLAG) {
@@ -1566,7 +1547,7 @@ again:
struct anon_vma_chain *vmac;
struct vm_area_struct *vma;
- spin_lock(&anon_vma->lock);
+ anon_vma_lock(anon_vma);
list_for_each_entry(vmac, &anon_vma->head, same_anon_vma) {
vma = vmac->vma;
if (rmap_item->address < vma->vm_start ||
@@ -1589,7 +1570,7 @@ again:
if (!search_new_forks || !mapcount)
break;
}
- spin_unlock(&anon_vma->lock);
+ anon_vma_unlock(anon_vma);
if (!mapcount)
goto out;
}
@@ -1619,7 +1600,7 @@ again:
struct anon_vma_chain *vmac;
struct vm_area_struct *vma;
- spin_lock(&anon_vma->lock);
+ anon_vma_lock(anon_vma);
list_for_each_entry(vmac, &anon_vma->head, same_anon_vma) {
vma = vmac->vma;
if (rmap_item->address < vma->vm_start ||
@@ -1637,11 +1618,11 @@ again:
ret = try_to_unmap_one(page, vma,
rmap_item->address, flags);
if (ret != SWAP_AGAIN || !page_mapped(page)) {
- spin_unlock(&anon_vma->lock);
+ anon_vma_unlock(anon_vma);
goto out;
}
}
- spin_unlock(&anon_vma->lock);
+ anon_vma_unlock(anon_vma);
}
if (!search_new_forks++)
goto again;
@@ -1671,7 +1652,7 @@ again:
struct anon_vma_chain *vmac;
struct vm_area_struct *vma;
- spin_lock(&anon_vma->lock);
+ anon_vma_lock(anon_vma);
list_for_each_entry(vmac, &anon_vma->head, same_anon_vma) {
vma = vmac->vma;
if (rmap_item->address < vma->vm_start ||
@@ -1688,11 +1669,11 @@ again:
ret = rmap_one(page, vma, rmap_item->address, arg);
if (ret != SWAP_AGAIN) {
- spin_unlock(&anon_vma->lock);
+ anon_vma_unlock(anon_vma);
goto out;
}
}
- spin_unlock(&anon_vma->lock);
+ anon_vma_unlock(anon_vma);
}
if (!search_new_forks++)
goto again;
@@ -1943,15 +1924,11 @@ static int __init ksm_init(void)
if (err)
goto out;
- err = mm_slots_hash_init();
- if (err)
- goto out_free1;
-
ksm_thread = kthread_run(ksm_scan_thread, NULL, "ksmd");
if (IS_ERR(ksm_thread)) {
printk(KERN_ERR "ksm: creating kthread failed\n");
err = PTR_ERR(ksm_thread);
- goto out_free2;
+ goto out_free;
}
#ifdef CONFIG_SYSFS
@@ -1959,7 +1936,7 @@ static int __init ksm_init(void)
if (err) {
printk(KERN_ERR "ksm: register sysfs failed\n");
kthread_stop(ksm_thread);
- goto out_free2;
+ goto out_free;
}
#else
ksm_run = KSM_RUN_MERGE; /* no way for user to start it */
@@ -1975,9 +1952,7 @@ static int __init ksm_init(void)
#endif
return 0;
-out_free2:
- mm_slots_hash_free();
-out_free1:
+out_free:
ksm_slab_free();
out:
return err;
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.