[PATCH v3 6/7] slab: Use slab_list instead of lru

Tobin C. Harding
2019-03-14T05:32:35Z

Currently we use the page->lru list for maintaining lists of slabs. We
have a list in the page structure (slab_list) that can be used for this
purpose. Doing so makes the code cleaner since we are not overloading
the lru list.

Use the slab_list instead of the lru list for maintaining lists of
slabs.

Reviewed-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Tobin C. Harding <tobin@kernel.org>
---
mm/slab.c | 49 +++++++++++++++++++++++++------------------------
1 file changed, 25 insertions(+), 24 deletions(-)

diff --git a/mm/slab.c b/mm/slab.c
index 28652e4218e0..09cc64ef9613 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1710,8 +1710,8 @@ static void slabs_destroy(struct kmem_cache *cachep, struct list_head *list)
{
struct page *page, *n;

- list_for_each_entry_safe(page, n, list, lru) {
- list_del(&page->lru);
+ list_for_each_entry_safe(page, n, list, slab_list) {
+ list_del(&page->slab_list);
slab_destroy(cachep, page);
}
}
@@ -2265,8 +2265,8 @@ static int drain_freelist(struct kmem_cache *cache,
goto out;
}

- page = list_entry(p, struct page, lru);
- list_del(&page->lru);
+ page = list_entry(p, struct page, slab_list);
+ list_del(&page->slab_list);
n->free_slabs--;
n->total_slabs--;
/*
@@ -2726,13 +2726,13 @@ static void cache_grow_end(struct kmem_cache *cachep, struct page *page)
if (!page)
return;

- INIT_LIST_HEAD(&page->lru);
+ INIT_LIST_HEAD(&page->slab_list);
n = get_node(cachep, page_to_nid(page));

spin_lock(&n->list_lock);
n->total_slabs++;
if (!page->active) {
- list_add_tail(&page->lru, &(n->slabs_free));
+ list_add_tail(&page->slab_list, &n->slabs_free);
n->free_slabs++;
} else
fixup_slab_list(cachep, n, page, &list);
@@ -2841,9 +2841,9 @@ static inline void fixup_slab_list(struct kmem_cache *cachep,
void **list)
{
/* move slabp to correct slabp list: */
- list_del(&page->lru);
+ list_del(&page->slab_list);
if (page->active == cachep->num) {
- list_add(&page->lru, &n->slabs_full);
+ list_add(&page->slab_list, &n->slabs_full);
if (OBJFREELIST_SLAB(cachep)) {
#if DEBUG
/* Poisoning will be done without holding the lock */
@@ -2857,7 +2857,7 @@ static inline void fixup_slab_list(struct kmem_cache *cachep,
page->freelist = NULL;
}
} else
- list_add(&page->lru, &n->slabs_partial);
+ list_add(&page->slab_list, &n->slabs_partial);
}

/* Try to find non-pfmemalloc slab if needed */
@@ -2880,20 +2880,20 @@ static noinline struct page *get_valid_first_slab(struct kmem_cache_node *n,
}

/* Move pfmemalloc slab to the end of list to speed up next search */
- list_del(&page->lru);
+ list_del(&page->slab_list);
if (!page->active) {
- list_add_tail(&page->lru, &n->slabs_free);
+ list_add_tail(&page->slab_list, &n->slabs_free);
n->free_slabs++;
} else
- list_add_tail(&page->lru, &n->slabs_partial);
+ list_add_tail(&page->slab_list, &n->slabs_partial);

- list_for_each_entry(page, &n->slabs_partial, lru) {
+ list_for_each_entry(page, &n->slabs_partial, slab_list) {
if (!PageSlabPfmemalloc(page))
return page;
}

n->free_touched = 1;
- list_for_each_entry(page, &n->slabs_free, lru) {
+ list_for_each_entry(page, &n->slabs_free, slab_list) {
if (!PageSlabPfmemalloc(page)) {
n->free_slabs--;
return page;
@@ -2908,11 +2908,12 @@ static struct page *get_first_slab(struct kmem_cache_node *n, bool pfmemalloc)
struct page *page;

assert_spin_locked(&n->list_lock);
- page = list_first_entry_or_null(&n->slabs_partial, struct page, lru);
+ page = list_first_entry_or_null(&n->slabs_partial, struct page,
+ slab_list);
if (!page) {
n->free_touched = 1;
page = list_first_entry_or_null(&n->slabs_free, struct page,
- lru);
+ slab_list);
if (page)
n->free_slabs--;
}
@@ -3413,29 +3414,29 @@ static void free_block(struct kmem_cache *cachep, void **objpp,
objp = objpp[i];

page = virt_to_head_page(objp);
- list_del(&page->lru);
+ list_del(&page->slab_list);
check_spinlock_acquired_node(cachep, node);
slab_put_obj(cachep, page, objp);
STATS_DEC_ACTIVE(cachep);

/* fixup slab chains */
if (page->active == 0) {
- list_add(&page->lru, &n->slabs_free);
+ list_add(&page->slab_list, &n->slabs_free);
n->free_slabs++;
} else {
/* Unconditionally move a slab to the end of the
* partial list on free - maximum time for the
* other objects to be freed, too.
*/
- list_add_tail(&page->lru, &n->slabs_partial);
+ list_add_tail(&page->slab_list, &n->slabs_partial);
}
}

while (n->free_objects > n->free_limit && !list_empty(&n->slabs_free)) {
n->free_objects -= cachep->num;

- page = list_last_entry(&n->slabs_free, struct page, lru);
- list_move(&page->lru, list);
+ page = list_last_entry(&n->slabs_free, struct page, slab_list);
+ list_move(&page->slab_list, list);
n->free_slabs--;
n->total_slabs--;
}
@@ -3473,7 +3474,7 @@ static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac)
int i = 0;
struct page *page;

- list_for_each_entry(page, &n->slabs_free, lru) {
+ list_for_each_entry(page, &n->slabs_free, slab_list) {
BUG_ON(page->active);

i++;
@@ -4336,9 +4337,9 @@ static int leaks_show(struct seq_file *m, void *p)
check_irq_on();
spin_lock_irq(&n->list_lock);

- list_for_each_entry(page, &n->slabs_full, lru)
+ list_for_each_entry(page, &n->slabs_full, slab_list)
handle_slab(x, cachep, page);
- list_for_each_entry(page, &n->slabs_partial, lru)
+ list_for_each_entry(page, &n->slabs_partial, slab_list)
handle_slab(x, cachep, page);
spin_unlock_irq(&n->list_lock);
}
--
2.21.0