] mm: Use slab_list list_head instead of lru

PATCH Superseded Tobin C. Harding 3 participants 11 messages Mar 13, 2019 – Mar 14, 2019

Subsystems (3)

Memory management MM core Slab allocator

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Tobin C. Harding

author

2019-03-13 05:21 UTC #0 lore raw

v2 cover ] mm: Use slab_list list_head instead of lru

Currently the slab allocators (ab)use the struct page 'lru' list_head. We have a list head for slab allocators to use, 'slab_list'.

Clean up all three allocators by using the 'slab_list' list_head instead of overloading the 'lru' list_head.

Patch 1 - Makes no code changes, adds comments to #endif statements.

Patches 2,3,4 - Do changes as a patch per allocator, tested by building
and booting (in Qemu) after configuring kernel to use appropriate allocator. Also build and boot with debug options enabled (for slab and slub). Verify the object files (before and after the set applied) are the same.

Patch 5 - Removes the now stale comment in the page struct definition.

Changes since v1:

- Verify object files are the same before and after the patch set is applied (suggested by Matthew).
- Add extra explanation to the commit logs explaining why these changes are safe to make (suggested by Roman).
- Remove stale comment (thanks Willy).

thanks,
Tobin.

Tobin C. Harding (5):
slub: Add comments to endif pre-processor macros
slub: Use slab_list instead of lru
slab: Use slab_list instead of lru
slob: Use slab_list instead of lru
mm: Remove stale comment from page struct

 include/linux/mm_types.h |  2 +-
 mm/slab.c                | 49 ++++++++++++++++----------------
 mm/slob.c                | 10 +++----
 mm/slub.c                | 60 ++++++++++++++++++++--------------------
 4 files changed, 61 insertions(+), 60 deletions(-)

Signature · 1 line

2.21.0

Tobin C. Harding

author

2019-03-13 05:21 UTC #1 lore raw

PATCH v2 1/5 slub: Add comments to endif pre-processor macros

SLUB allocator makes heavy use of ifdef/endif pre-processor macros. The pairing of these statements is at times hard to follow e.g. if the pair are further than a screen apart or if there are nested pairs. We can reduce cognitive load by adding a comment to the endif statement of form

       #ifdef CONFIG_FOO
       ...
       #endif /* CONFIG_FOO */

Add comments to endif pre-processor macros if ifdef/endif pair is not immediately apparent.

Reviewed-by Roman Gushchin <[email protected]>

Signed-off-by Tobin C. Harding <[email protected]>

---
 mm/slub.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

mm/slub.c +10 ~~-10~~

index 1b08fbcb7e61..b282e22885cd 100644
@@ -1951,7 +1951,7 @@ static void *get_any_partial(struct kmem_cache *s, gfp_t flags,
 			}
 		}
 	} while (read_mems_allowed_retry(cpuset_mems_cookie));
-#endif
+#endif	/* CONFIG_NUMA */
 	return NULL;
 }

@@ -2249,7 +2249,7 @@ static void unfreeze_partials(struct kmem_cache *s,
 		discard_slab(s, page);
 		stat(s, FREE_SLAB);
 	}
-#endif
+#endif	/* CONFIG_SLUB_CPU_PARTIAL */
 }
 
 /*

@@ -2308,7 +2308,7 @@ static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
 		local_irq_restore(flags);
 	}
 	preempt_enable();
-#endif
+#endif	/* CONFIG_SLUB_CPU_PARTIAL */
 }
 
 static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)

@@ -2813,7 +2813,7 @@ void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
 }
 EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
 #endif
-#endif
+#endif	/* CONFIG_NUMA */
 
 /*
  * Slow path handling. This may still be called frequently since objects

@@ -3845,7 +3845,7 @@ void *__kmalloc_node(size_t size, gfp_t flags, int node)
 	return ret;
 }
 EXPORT_SYMBOL(__kmalloc_node);
-#endif
+#endif	/* CONFIG_NUMA */
 
 #ifdef CONFIG_HARDENED_USERCOPY
 /*

@@ -4063,7 +4063,7 @@ void __kmemcg_cache_deactivate(struct kmem_cache *s)
 	 */
 	slab_deactivate_memcg_cache_rcu_sched(s, kmemcg_cache_deact_after_rcu);
 }
-#endif
+#endif	/* CONFIG_MEMCG */
 
 static int slab_mem_going_offline_callback(void *arg)
 {

@@ -4696,7 +4696,7 @@ static int list_locations(struct kmem_cache *s, char *buf,
 		len += sprintf(buf, "No data\n");
 	return len;
 }
-#endif
+#endif	/* CONFIG_SLUB_DEBUG */
 
 #ifdef SLUB_RESILIENCY_TEST
 static void __init resiliency_test(void)

@@ -4756,7 +4756,7 @@ static void __init resiliency_test(void)
 #ifdef CONFIG_SYSFS
 static void resiliency_test(void) {};
 #endif
-#endif
+#endif	/* SLUB_RESILIENCY_TEST */
 
 #ifdef CONFIG_SYSFS
 enum slab_stat_type {

@@ -5413,7 +5413,7 @@ STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc);
 STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free);
 STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node);
 STAT_ATTR(CPU_PARTIAL_DRAIN, cpu_partial_drain);
-#endif
+#endif	/* CONFIG_SLUB_STATS */
 
 static struct attribute *slab_attrs[] = {
 	&slab_size_attr.attr,

@@ -5614,7 +5614,7 @@ static void memcg_propagate_slab_attrs(struct kmem_cache *s)
 
 	if (buffer)
 		free_page((unsigned long)buffer);
-#endif
+#endif	/* CONFIG_MEMCG */
 }
 
 static void kmem_cache_release(struct kobject *k)

Signature · 1 line

2.21.0

Christopher Lameter

Acked-by on v2 1/5

2019-03-13 19:00 UTC #2 lore raw

Re: [PATCH v2 1/5] slub: Add comments to endif pre-processor macros

Acked-by Christoph Lameter <[email protected]>

Tobin C. Harding

author

2019-03-13 05:21 UTC #3 lore raw

PATCH v2 2/5 slub: Use slab_list instead of lru

In reply to Tobin C. Harding

Currently we use the page->lru list for maintaining lists of slabs. We have a list_head 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.

The slab_list is part of a union within the page struct (included here stripped down):

	union {
		struct {	/* Page cache and anonymous pages */
			struct list_head lru;
			...
		};
		struct {
			dma_addr_t dma_addr;
		};
		struct {	/* slab, slob and slub */
			union {
				struct list_head slab_list;
				struct {	/* Partial pages */
					struct page *next;
					int pages;	/* Nr of pages left */
					int pobjects;	/* Approximate count */
				};
			};
		...

Here we see that slab_list and lru are the same bits. We can verify that this change is safe to do by examining the object file produced from slub.c before and after this patch is applied.

Steps taken to verify:

1. checkout current tip of Linus' tree

commit a667cb7a94d4 ("Merge branch 'akpm' (patches from Andrew)")

2. configure and build (defaults to SLUB allocator)

CONFIG_SLUB=y
CONFIG_SLUB_DEBUG=y
CONFIG_SLUB_DEBUG_ON=y
CONFIG_SLUB_STATS=y
CONFIG_HAVE_DEBUG_KMEMLEAK=y
CONFIG_SLAB_FREELIST_RANDOM=y
CONFIG_SLAB_FREELIST_HARDENED=y

3. dissasemble object file `objdump -dr mm/slub.o > before.s
4. apply patch
5. build
6. dissasemble object file `objdump -dr mm/slub.o > after.s
7. diff before.s after.s

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

Reviewed-by Roman Gushchin <[email protected]>

Signed-off-by Tobin C. Harding <[email protected]>

---
 mm/slub.c | 40 ++++++++++++++++++++--------------------
 1 file changed, 20 insertions(+), 20 deletions(-)

mm/slub.c +20 ~~-20~~

index b282e22885cd..d692b5e0163d 100644
@@ -1023,7 +1023,7 @@ static void add_full(struct kmem_cache *s,
 		return;
 
 	lockdep_assert_held(&n->list_lock);
-	list_add(&page->lru, &n->full);
+	list_add(&page->slab_list, &n->full);
 }
 
 static void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, struct page *page)

@@ -1032,7 +1032,7 @@ static void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, struct
 		return;
 
 	lockdep_assert_held(&n->list_lock);
-	list_del(&page->lru);
+	list_del(&page->slab_list);
 }
 
 /* Tracking of the number of slabs for debugging purposes */

@@ -1773,9 +1773,9 @@ __add_partial(struct kmem_cache_node *n, struct page *page, int tail)
 {
 	n->nr_partial++;
 	if (tail == DEACTIVATE_TO_TAIL)
-		list_add_tail(&page->lru, &n->partial);
+		list_add_tail(&page->slab_list, &n->partial);
 	else
-		list_add(&page->lru, &n->partial);
+		list_add(&page->slab_list, &n->partial);
 }
 
 static inline void add_partial(struct kmem_cache_node *n,

@@ -1789,7 +1789,7 @@ static inline void remove_partial(struct kmem_cache_node *n,
 					struct page *page)
 {
 	lockdep_assert_held(&n->list_lock);
-	list_del(&page->lru);
+	list_del(&page->slab_list);
 	n->nr_partial--;
 }

@@ -1863,7 +1863,7 @@ static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
 		return NULL;
 
 	spin_lock(&n->list_lock);
-	list_for_each_entry_safe(page, page2, &n->partial, lru) {
+	list_for_each_entry_safe(page, page2, &n->partial, slab_list) {
 		void *t;
 
 		if (!pfmemalloc_match(page, flags))

@@ -2407,7 +2407,7 @@ static unsigned long count_partial(struct kmem_cache_node *n,
 	struct page *page;
 
 	spin_lock_irqsave(&n->list_lock, flags);
-	list_for_each_entry(page, &n->partial, lru)
+	list_for_each_entry(page, &n->partial, slab_list)
 		x += get_count(page);
 	spin_unlock_irqrestore(&n->list_lock, flags);
 	return x;

@@ -3702,10 +3702,10 @@ static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
 
 	BUG_ON(irqs_disabled());
 	spin_lock_irq(&n->list_lock);
-	list_for_each_entry_safe(page, h, &n->partial, lru) {
+	list_for_each_entry_safe(page, h, &n->partial, slab_list) {
 		if (!page->inuse) {
 			remove_partial(n, page);
-			list_add(&page->lru, &discard);
+			list_add(&page->slab_list, &discard);
 		} else {
 			list_slab_objects(s, page,
 			"Objects remaining in %s on __kmem_cache_shutdown()");

@@ -3713,7 +3713,7 @@ static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
 	}
 	spin_unlock_irq(&n->list_lock);
 
-	list_for_each_entry_safe(page, h, &discard, lru)
+	list_for_each_entry_safe(page, h, &discard, slab_list)
 		discard_slab(s, page);
 }

@@ -3993,7 +3993,7 @@ int __kmem_cache_shrink(struct kmem_cache *s)
 		 * Note that concurrent frees may occur while we hold the
 		 * list_lock. page->inuse here is the upper limit.
 		 */
-		list_for_each_entry_safe(page, t, &n->partial, lru) {
+		list_for_each_entry_safe(page, t, &n->partial, slab_list) {
 			int free = page->objects - page->inuse;
 
 			/* Do not reread page->inuse */

@@ -4003,10 +4003,10 @@ int __kmem_cache_shrink(struct kmem_cache *s)
 			BUG_ON(free <= 0);
 
 			if (free == page->objects) {
-				list_move(&page->lru, &discard);
+				list_move(&page->slab_list, &discard);
 				n->nr_partial--;
 			} else if (free <= SHRINK_PROMOTE_MAX)
-				list_move(&page->lru, promote + free - 1);
+				list_move(&page->slab_list, promote + free - 1);
 		}
 
 		/*

@@ -4019,7 +4019,7 @@ int __kmem_cache_shrink(struct kmem_cache *s)
 		spin_unlock_irqrestore(&n->list_lock, flags);
 
 		/* Release empty slabs */
-		list_for_each_entry_safe(page, t, &discard, lru)
+		list_for_each_entry_safe(page, t, &discard, slab_list)
 			discard_slab(s, page);
 
 		if (slabs_node(s, node))

@@ -4211,11 +4211,11 @@ static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache)
 	for_each_kmem_cache_node(s, node, n) {
 		struct page *p;
 
-		list_for_each_entry(p, &n->partial, lru)
+		list_for_each_entry(p, &n->partial, slab_list)
 			p->slab_cache = s;
 
 #ifdef CONFIG_SLUB_DEBUG
-		list_for_each_entry(p, &n->full, lru)
+		list_for_each_entry(p, &n->full, slab_list)
 			p->slab_cache = s;
 #endif
 	}

@@ -4432,7 +4432,7 @@ static int validate_slab_node(struct kmem_cache *s,
 
 	spin_lock_irqsave(&n->list_lock, flags);
 
-	list_for_each_entry(page, &n->partial, lru) {
+	list_for_each_entry(page, &n->partial, slab_list) {
 		validate_slab_slab(s, page, map);
 		count++;
 	}

@@ -4443,7 +4443,7 @@ static int validate_slab_node(struct kmem_cache *s,
 	if (!(s->flags & SLAB_STORE_USER))
 		goto out;
 
-	list_for_each_entry(page, &n->full, lru) {
+	list_for_each_entry(page, &n->full, slab_list) {
 		validate_slab_slab(s, page, map);
 		count++;
 	}

@@ -4639,9 +4639,9 @@ static int list_locations(struct kmem_cache *s, char *buf,
 			continue;
 
 		spin_lock_irqsave(&n->list_lock, flags);
-		list_for_each_entry(page, &n->partial, lru)
+		list_for_each_entry(page, &n->partial, slab_list)
 			process_slab(&t, s, page, alloc, map);
-		list_for_each_entry(page, &n->full, lru)
+		list_for_each_entry(page, &n->full, slab_list)
 			process_slab(&t, s, page, alloc, map);
 		spin_unlock_irqrestore(&n->list_lock, flags);
 	}

Signature · 1 line

2.21.0

Christopher Lameter

Acked-by on v2 2/5

2019-03-13 19:02 UTC #4 lore raw

Re: [PATCH v2 2/5] slub: Use slab_list instead of lru

Acked-by Christoph Lameter <[email protected]>

Tobin C. Harding

author

2019-03-13 05:21 UTC #5 lore raw

PATCH v2 3/5 slab: Use slab_list instead of lru

In reply to Tobin C. Harding

The slab_list is part of a union within the page struct (included here stripped down):

	union {
		struct {	/* Page cache and anonymous pages */
			struct list_head lru;
			...
		};
		struct {
			dma_addr_t dma_addr;
		};
		struct {	/* slab, slob and slub */
			union {
				struct list_head slab_list;
				struct {	/* Partial pages */
					struct page *next;
					int pages;	/* Nr of pages left */
					int pobjects;	/* Approximate count */
				};
			};
		...

Here we see that slab_list and lru are the same bits. We can verify that this change is safe to do by examining the object file produced from slab.c before and after this patch is applied.

Steps taken to verify:

1. checkout current tip of Linus' tree

commit a667cb7a94d4 ("Merge branch 'akpm' (patches from Andrew)")

2. configure and build (selecting SLAB allocator)

CONFIG_SLAB=y
CONFIG_SLAB_FREELIST_RANDOM=y
CONFIG_DEBUG_SLAB=y
CONFIG_DEBUG_SLAB_LEAK=y
CONFIG_HAVE_DEBUG_KMEMLEAK=y

3. dissasemble object file `objdump -dr mm/slab.o > before.s
4. apply patch
5. build
6. dissasemble object file `objdump -dr mm/slab.o > after.s
7. diff before.s after.s

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

Reviewed-by Roman Gushchin <[email protected]>

Signed-off-by Tobin C. Harding <[email protected]>

---
 mm/slab.c | 49 +++++++++++++++++++++++++------------------------
 1 file changed, 25 insertions(+), 24 deletions(-)

mm/slab.c +25 ~~-24~~

index 28652e4218e0..09cc64ef9613 100644
@@ -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);
 		}

Signature · 1 line

2.21.0

Tobin C. Harding

author

2019-03-13 05:21 UTC #6 lore raw

PATCH v2 4/5 slob: Use slab_list instead of lru

In reply to Tobin C. Harding

The slab_list is part of a union within the page struct (included here stripped down):

	union {
		struct {	/* Page cache and anonymous pages */
			struct list_head lru;
			...
		};
		struct {
			dma_addr_t dma_addr;
		};
		struct {	/* slab, slob and slub */
			union {
				struct list_head slab_list;
				struct {	/* Partial pages */
					struct page *next;
					int pages;	/* Nr of pages left */
					int pobjects;	/* Approximate count */
				};
			};
		...

Here we see that slab_list and lru are the same bits. We can verify that this change is safe to do by examining the object file produced from slob.c before and after this patch is applied.

Steps taken to verify:

1. checkout current tip of Linus' tree

commit a667cb7a94d4 ("Merge branch 'akpm' (patches from Andrew)")

2. configure and build (select SLOB allocator)

CONFIG_SLOB=y
CONFIG_SLAB_MERGE_DEFAULT=y

3. dissasemble object file `objdump -dr mm/slub.o > before.s
4. apply patch
5. build
6. dissasemble object file `objdump -dr mm/slub.o > after.s
7. diff before.s after.s

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

Reviewed-by Roman Gushchin <[email protected]>

Signed-off-by Tobin C. Harding <[email protected]>

---
 mm/slob.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

mm/slob.c +5 -5

index 307c2c9feb44..ee68ff2a2833 100644
@@ -112,13 +112,13 @@ static inline int slob_page_free(struct page *sp)
 
 static void set_slob_page_free(struct page *sp, struct list_head *list)
 {
-	list_add(&sp->lru, list);
+	list_add(&sp->slab_list, list);
 	__SetPageSlobFree(sp);
 }
 
 static inline void clear_slob_page_free(struct page *sp)
 {
-	list_del(&sp->lru);
+	list_del(&sp->slab_list);
 	__ClearPageSlobFree(sp);
 }

@@ -283,7 +283,7 @@ static void *slob_alloc(size_t size, gfp_t gfp, int align, int node)
 
 	spin_lock_irqsave(&slob_lock, flags);
 	/* Iterate through each partially free page, try to find room */
-	list_for_each_entry(sp, slob_list, lru) {
+	list_for_each_entry(sp, slob_list, slab_list) {
 #ifdef CONFIG_NUMA
 		/*
 		 * If there's a node specification, search for a partial

@@ -297,7 +297,7 @@ static void *slob_alloc(size_t size, gfp_t gfp, int align, int node)
 			continue;
 
 		/* Attempt to alloc */
-		prev = sp->lru.prev;
+		prev = sp->slab_list.prev;
 		b = slob_page_alloc(sp, size, align);
 		if (!b)
 			continue;

@@ -323,7 +323,7 @@ static void *slob_alloc(size_t size, gfp_t gfp, int align, int node)
 		spin_lock_irqsave(&slob_lock, flags);
 		sp->units = SLOB_UNITS(PAGE_SIZE);
 		sp->freelist = b;
-		INIT_LIST_HEAD(&sp->lru);
+		INIT_LIST_HEAD(&sp->slab_list);
 		set_slob(b, SLOB_UNITS(PAGE_SIZE), b + SLOB_UNITS(PAGE_SIZE));
 		set_slob_page_free(sp, slob_list);
 		b = slob_page_alloc(sp, size, align);

Signature · 1 line

2.21.0

Christopher Lameter

2019-03-13 19:05 UTC #7 lore raw

Re: [PATCH v2 4/5] slob: Use slab_list instead of lru

mm/slob.c static void *slob_alloc(size_t size, gfp_t gfp, int align, int node) · line 303

Quoted 9 lines · Tobin C. Harding

mm/slob.c +1 -1

@@ -297,7 +297,7 @@ static void *slob_alloc(size_t size, gfp_t gfp, int align, int node)
 			continue;
 
 		/* Attempt to alloc */
-		prev = sp->lru.prev;
+		prev = sp->slab_list.prev;
 		b = slob_page_alloc(sp, size, align);
 		if (!b)
 			continue;

Hmmm... Is there a way to use a macro or so to avoid referencing the field within the slab_list?

Tobin C. Harding

2019-03-14 03:24 UTC #8 lore raw

Re: [PATCH v2 4/5] slob: Use slab_list instead of lru

Quoted 5 lines · Christopher Lameter

Quoted 3 lines · Tobin C. Harding

mm/slob.c +0 -0

@@ -297,7 +297,7 @@ static void *slob_alloc(size_t size, gfp_t gfp, int align, int node)
 			continue;

Quoted 9 lines

mm/slob.c static void *slob_alloc(size_t size, gfp_t gfp, int align, int node) · line 303
Quoted 6 lines
mm/slob.c +1 -1
 		/* Attempt to alloc */
-		prev = sp->lru.prev;
+		prev = sp->slab_list.prev;
 		b = slob_page_alloc(sp, size, align);
 		if (!b)
 			continue;
Hmmm... Is there a way to use a macro or so to avoid referencing the field within the slab_list?

Thanks for the review. Next version includes a fix for this.

Tobin.

Tobin C. Harding

author

2019-03-13 05:21 UTC #9 lore raw

PATCH v2 5/5 mm: Remove stale comment from page struct

In reply to Tobin C. Harding

We now use the slab_list list_head instead of the lru list_head. This comment has become stale.

Remove stale comment from page struct slab_list list_head.

Signed-off-by Tobin C. Harding <[email protected]>

---
 include/linux/mm_types.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

include/linux/mm_types.h +1 -1

index 7eade9132f02..63a34e3d7c29 100644
@@ -103,7 +103,7 @@ struct page {
 		};
 		struct {	/* slab, slob and slub */
 			union {
-				struct list_head slab_list;	/* uses lru */
+				struct list_head slab_list;
 				struct {	/* Partial pages */
 					struct page *next;
 #ifdef CONFIG_64BIT

Signature · 1 line

2.21.0

Christopher Lameter

Acked-by on v2 5/5

2019-03-13 19:05 UTC #10 lore raw

Re: [PATCH v2 5/5] mm: Remove stale comment from page struct

Acked-by Christoph Lameter <[email protected]>