On Mon, 17 Dec 2012, Sasha Levin wrote:
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index 827d9c8..2a0ef01 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -20,6 +20,7 @@
> #include <linux/mman.h>
> #include <linux/pagemap.h>
>
> +#include <linux/hashtable.h>
> #include <asm/tlb.h>
> #include <asm/pgalloc.h>
> #include "internal.h"
Why group this with the asm includes?
> @@ -61,12 +62,12 @@ static DECLARE_WAIT_QUEUE_HEAD(khugepaged_wait);
> static unsigned int khugepaged_max_ptes_none __read_mostly = HPAGE_PMD_NR-1;
>
> static int khugepaged(void *none);
> -static int mm_slots_hash_init(void);
> static int khugepaged_slab_init(void);
> static void khugepaged_slab_free(void);
>
You're removing khugepaged_slab_free() too.
> -#define MM_SLOTS_HASH_HEADS 1024
> -static struct hlist_head *mm_slots_hash __read_mostly;
> +#define MM_SLOTS_HASH_BITS 10
> +static DEFINE_HASHTABLE(mm_slots_hash, MM_SLOTS_HASH_BITS);
> +
What happened to the __read_mostly?
This used to be dynamically allocated and would save the 8KB that you
statically allocate if transparent hugepages cannot be used. The generic
hashtable implementation does not support dynamic allocation?
> static struct kmem_cache *mm_slot_cache __read_mostly;
>
> /**
> @@ -633,12 +634,6 @@ static int __init hugepage_init(void)
> if (err)
> goto out;
>
> - err = mm_slots_hash_init();
> - if (err) {
> - khugepaged_slab_free();
This is the only use of khugepaged_slab_free(), so the function should be
removed as well.
> - goto out;
> - }
> -
> register_shrinker(&huge_zero_page_shrinker);
>
> /*
> @@ -1821,47 +1816,23 @@ 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;
> -}
> -
> -#if 0
> -static void __init mm_slots_hash_free(void)
> -{
> - kfree(mm_slots_hash);
> - mm_slots_hash = NULL;
> -}
> -#endif
> -
> static struct mm_slot *get_mm_slot(struct mm_struct *mm)
> {
> - struct mm_slot *mm_slot;
> - struct hlist_head *bucket;
> + struct mm_slot *slot;
> struct hlist_node *node;
>
> - bucket = &mm_slots_hash[((unsigned long)mm / sizeof(struct mm_struct))
> - % MM_SLOTS_HASH_HEADS];
> - hlist_for_each_entry(mm_slot, node, bucket, hash) {
> - if (mm == mm_slot->mm)
> - return mm_slot;
> - }
> + hash_for_each_possible(mm_slots_hash, slot, node, hash, (unsigned long) mm)
> + if (slot->mm == mm)
> + return slot;
Why these other changes (the naming of the variable, the ordering of the
conditional)?
> +
> 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[((unsigned long)mm / sizeof(struct mm_struct))
> - % MM_SLOTS_HASH_HEADS];
> mm_slot->mm = mm;
> - hlist_add_head(&mm_slot->hash, bucket);
> + hash_add(mm_slots_hash, &mm_slot->hash, (long)mm);
> }
>
> static inline int khugepaged_test_exit(struct mm_struct *mm)
> @@ -1930,7 +1901,7 @@ void __khugepaged_exit(struct mm_struct *mm)
> spin_lock(&khugepaged_mm_lock);
> mm_slot = get_mm_slot(mm);
> if (mm_slot && khugepaged_scan.mm_slot != mm_slot) {
> - hlist_del(&mm_slot->hash);
> + hash_del(&mm_slot->hash);
> list_del(&mm_slot->mm_node);
> free = 1;
> }
> @@ -2379,7 +2350,7 @@ static void collect_mm_slot(struct mm_slot *mm_slot)
>
> if (khugepaged_test_exit(mm)) {
> /* free mm_slot */
> - hlist_del(&mm_slot->hash);
> + hash_del(&mm_slot->hash);
> list_del(&mm_slot->mm_node);
>
> /*
--
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