On Mon, 17 Dec 2012, Sasha Levin wrote:
> Switch ksm to use the new hashtable implementation. This reduces the amount of
> generic unrelated code in the ksm module.
>
> This patch depends on d9b482c ("hashtable: introduce a small and naive
> hashtable") which was merged in v3.6.
>
> Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
This seems fine, thanks:
except please drop that irrelevant final hunk to ksm_init(), then
Acked-by: Hugh Dickins <hughd@xxxxxxxxxx>
> ---
> mm/ksm.c | 31 +++++++++++++------------------
> 1 file changed, 13 insertions(+), 18 deletions(-)
>
> diff --git a/mm/ksm.c b/mm/ksm.c
> index 382d930..e888f54 100644
> --- a/mm/ksm.c
> +++ b/mm/ksm.c
> @@ -33,7 +33,7 @@
> #include <linux/mmu_notifier.h>
> #include <linux/swap.h>
> #include <linux/ksm.h>
> -#include <linux/hash.h>
> +#include <linux/hashtable.h>
> #include <linux/freezer.h>
> #include <linux/oom.h>
>
> @@ -156,9 +156,8 @@ 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_SHIFT 10
> -#define MM_SLOTS_HASH_HEADS (1 << MM_SLOTS_HASH_SHIFT)
> -static struct hlist_head mm_slots_hash[MM_SLOTS_HASH_HEADS];
> +#define MM_SLOTS_HASH_BITS 10
> +static DEFINE_HASHTABLE(mm_slots_hash, MM_SLOTS_HASH_BITS);
>
> static struct mm_slot ksm_mm_head = {
> .mm_list = LIST_HEAD_INIT(ksm_mm_head.mm_list),
> @@ -275,26 +274,21 @@ static inline void free_mm_slot(struct mm_slot *mm_slot)
>
> static struct mm_slot *get_mm_slot(struct mm_struct *mm)
> {
> - struct mm_slot *mm_slot;
> - struct hlist_head *bucket;
> struct hlist_node *node;
> + struct mm_slot *slot;
> +
> + hash_for_each_possible(mm_slots_hash, slot, node, link, (unsigned long)mm)
> + if (slot->mm == mm)
> + return slot;
>
> - 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;
> - }
> return NULL;
> }
>
> static void insert_to_mm_slots_hash(struct mm_struct *mm,
> struct mm_slot *mm_slot)
> {
> - struct hlist_head *bucket;
> -
> - bucket = &mm_slots_hash[hash_ptr(mm, MM_SLOTS_HASH_SHIFT)];
> mm_slot->mm = mm;
> - hlist_add_head(&mm_slot->link, bucket);
> + hash_add(mm_slots_hash, &mm_slot->link, (unsigned long)mm);
> }
>
> static inline int in_stable_tree(struct rmap_item *rmap_item)
> @@ -647,7 +641,7 @@ static int unmerge_and_remove_all_rmap_items(void)
> ksm_scan.mm_slot = list_entry(mm_slot->mm_list.next,
> struct mm_slot, mm_list);
> if (ksm_test_exit(mm)) {
> - hlist_del(&mm_slot->link);
> + hash_del(&mm_slot->link);
> list_del(&mm_slot->mm_list);
> spin_unlock(&ksm_mmlist_lock);
>
> @@ -1392,7 +1386,7 @@ next_mm:
> * or when all VM_MERGEABLE areas have been unmapped (and
> * mmap_sem then protects against race with MADV_MERGEABLE).
> */
> - hlist_del(&slot->link);
> + hash_del(&slot->link);
> list_del(&slot->mm_list);
> spin_unlock(&ksm_mmlist_lock);
>
> @@ -1559,7 +1553,7 @@ void __ksm_exit(struct mm_struct *mm)
> mm_slot = get_mm_slot(mm);
> if (mm_slot && ksm_scan.mm_slot != mm_slot) {
> if (!mm_slot->rmap_list) {
> - hlist_del(&mm_slot->link);
> + hash_del(&mm_slot->link);
> list_del(&mm_slot->mm_list);
> easy_to_free = 1;
> } else {
> @@ -2035,6 +2029,7 @@ static int __init ksm_init(void)
> */
> hotplug_memory_notifier(ksm_memory_callback, 100);
> #endif
> +
> return 0;
>
> out_free:
> --
> 1.8.0
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