summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2023-04-25 13:00:41 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2023-04-25 13:00:41 -0700
commit736b378b29d89c8c3567fa4b2e948be5568aebb8 (patch)
tree4a97f3b2f465725d0a0b2fa62c26e3eaca738697
parent11704531dde45bc667a411e1c76de81d9f4481b8 (diff)
parented4cdfbeb8735c36a2e31009866dfc2dfa26db3f (diff)
Merge tag 'slab-for-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab
Pull slab updates from Vlastimil Babka: "The main change is naturally the SLOB removal. Since its deprecation in 6.2 I've seen no complaints so hopefully SLUB_(TINY) works well for everyone and we can proceed. Besides the code cleanup, the main immediate benefit will be allowing kfree() family of function to work on kmem_cache_alloc() objects, which was incompatible with SLOB. This includes kfree_rcu() which had no kmem_cache_free_rcu() counterpart yet and now it shouldn't be necessary anymore. Besides that, there are several small code and comment improvements from Thomas, Thorsten and Vernon" * tag 'slab-for-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab: mm/slab: document kfree() as allowed for kmem_cache_alloc() objects mm/slob: remove slob.c mm/slab: remove CONFIG_SLOB code from slab common code mm, pagemap: remove SLOB and SLQB from comments and documentation mm, page_flags: remove PG_slob_free mm/slob: remove CONFIG_SLOB mm/slub: fix help comment of SLUB_DEBUG mm: slub: make kobj_type structure constant slab: Adjust comment after refactoring of gfp.h
-rw-r--r--Documentation/admin-guide/mm/pagemap.rst6
-rw-r--r--Documentation/core-api/memory-allocation.rst17
-rw-r--r--fs/proc/page.c9
-rw-r--r--include/linux/page-flags.h4
-rw-r--r--include/linux/rcupdate.h6
-rw-r--r--include/linux/slab.h41
-rw-r--r--init/Kconfig2
-rw-r--r--kernel/configs/tiny.config1
-rw-r--r--mm/Kconfig22
-rw-r--r--mm/Kconfig.debug6
-rw-r--r--mm/Makefile2
-rw-r--r--mm/slab.h61
-rw-r--r--mm/slab_common.c7
-rw-r--r--mm/slob.c757
-rw-r--r--mm/slub.c2
-rw-r--r--tools/mm/page-types.c6
16 files changed, 32 insertions, 917 deletions
diff --git a/Documentation/admin-guide/mm/pagemap.rst b/Documentation/admin-guide/mm/pagemap.rst
index b5f970dc91e7..c8f380271cad 100644
--- a/Documentation/admin-guide/mm/pagemap.rst
+++ b/Documentation/admin-guide/mm/pagemap.rst
@@ -91,9 +91,9 @@ Short descriptions to the page flags
The page is being locked for exclusive access, e.g. by undergoing read/write
IO.
7 - SLAB
- The page is managed by the SLAB/SLOB/SLUB/SLQB kernel memory allocator.
- When compound page is used, SLUB/SLQB will only set this flag on the head
- page; SLOB will not flag it at all.
+ The page is managed by the SLAB/SLUB kernel memory allocator.
+ When compound page is used, either will only set this flag on the head
+ page.
10 - BUDDY
A free memory block managed by the buddy system allocator.
The buddy system organizes free memory in blocks of various orders.
diff --git a/Documentation/core-api/memory-allocation.rst b/Documentation/core-api/memory-allocation.rst
index 5954ddf6ee13..1c58d883b273 100644
--- a/Documentation/core-api/memory-allocation.rst
+++ b/Documentation/core-api/memory-allocation.rst
@@ -170,7 +170,16 @@ should be used if a part of the cache might be copied to the userspace.
After the cache is created kmem_cache_alloc() and its convenience
wrappers can allocate memory from that cache.
-When the allocated memory is no longer needed it must be freed. You can
-use kvfree() for the memory allocated with `kmalloc`, `vmalloc` and
-`kvmalloc`. The slab caches should be freed with kmem_cache_free(). And
-don't forget to destroy the cache with kmem_cache_destroy().
+When the allocated memory is no longer needed it must be freed.
+
+Objects allocated by `kmalloc` can be freed by `kfree` or `kvfree`. Objects
+allocated by `kmem_cache_alloc` can be freed with `kmem_cache_free`, `kfree`
+or `kvfree`, where the latter two might be more convenient thanks to not
+needing the kmem_cache pointer.
+
+The same rules apply to _bulk and _rcu flavors of freeing functions.
+
+Memory allocated by `vmalloc` can be freed with `vfree` or `kvfree`.
+Memory allocated by `kvmalloc` can be freed with `kvfree`.
+Caches created by `kmem_cache_create` should be freed with
+`kmem_cache_destroy` only after freeing all the allocated objects first.
diff --git a/fs/proc/page.c b/fs/proc/page.c
index 6249c347809a..195b077c0fac 100644
--- a/fs/proc/page.c
+++ b/fs/proc/page.c
@@ -125,7 +125,7 @@ u64 stable_page_flags(struct page *page)
/*
* pseudo flags for the well known (anonymous) memory mapped pages
*
- * Note that page->_mapcount is overloaded in SLOB/SLUB/SLQB, so the
+ * Note that page->_mapcount is overloaded in SLAB, so the
* simple test in page_mapped() is not enough.
*/
if (!PageSlab(page) && page_mapped(page))
@@ -165,9 +165,8 @@ u64 stable_page_flags(struct page *page)
/*
- * Caveats on high order pages: page->_refcount will only be set
- * -1 on the head page; SLUB/SLQB do the same for PG_slab;
- * SLOB won't set PG_slab at all on compound pages.
+ * Caveats on high order pages: PG_buddy and PG_slab will only be set
+ * on the head page.
*/
if (PageBuddy(page))
u |= 1 << KPF_BUDDY;
@@ -185,7 +184,7 @@ u64 stable_page_flags(struct page *page)
u |= kpf_copy_bit(k, KPF_LOCKED, PG_locked);
u |= kpf_copy_bit(k, KPF_SLAB, PG_slab);
- if (PageTail(page) && PageSlab(compound_head(page)))
+ if (PageTail(page) && PageSlab(page))
u |= 1 << KPF_SLAB;
u |= kpf_copy_bit(k, KPF_ERROR, PG_error);
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index a7e3a3405520..2bdc41cb0594 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -174,9 +174,6 @@ enum pageflags {
/* Remapped by swiotlb-xen. */
PG_xen_remapped = PG_owner_priv_1,
- /* SLOB */
- PG_slob_free = PG_private,
-
#ifdef CONFIG_MEMORY_FAILURE
/*
* Compound pages. Stored in first tail page's flags.
@@ -483,7 +480,6 @@ PAGEFLAG(Active, active, PF_HEAD) __CLEARPAGEFLAG(Active, active, PF_HEAD)
PAGEFLAG(Workingset, workingset, PF_HEAD)
TESTCLEARFLAG(Workingset, workingset, PF_HEAD)
__PAGEFLAG(Slab, slab, PF_NO_TAIL)
-__PAGEFLAG(SlobFree, slob_free, PF_NO_TAIL)
PAGEFLAG(Checked, checked, PF_NO_COMPOUND) /* Used by some filesystems */
/* Xen */
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 094321c17e48..dcd2cf1e8326 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -976,8 +976,10 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
* either fall back to use of call_rcu() or rearrange the structure to
* position the rcu_head structure into the first 4096 bytes.
*
- * Note that the allowable offset might decrease in the future, for example,
- * to allow something like kmem_cache_free_rcu().
+ * The object to be freed can be allocated either by kmalloc() or
+ * kmem_cache_alloc().
+ *
+ * Note that the allowable offset might decrease in the future.
*
* The BUILD_BUG_ON check must not involve any function calls, hence the
* checks are done in macros here.
diff --git a/include/linux/slab.h b/include/linux/slab.h
index 45af70315a94..7db48f9f0d9d 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -298,19 +298,6 @@ static inline unsigned int arch_slab_minalign(void)
#endif
#endif
-#ifdef CONFIG_SLOB
-/*
- * SLOB passes all requests larger than one page to the page allocator.
- * No kmalloc array is necessary since objects of different sizes can
- * be allocated from the same page.
- */
-#define KMALLOC_SHIFT_HIGH PAGE_SHIFT
-#define KMALLOC_SHIFT_MAX (MAX_ORDER + PAGE_SHIFT - 1)
-#ifndef KMALLOC_SHIFT_LOW
-#define KMALLOC_SHIFT_LOW 3
-#endif
-#endif
-
/* Maximum allocatable size */
#define KMALLOC_MAX_SIZE (1UL << KMALLOC_SHIFT_MAX)
/* Maximum size for which we actually use a slab cache */
@@ -366,7 +353,6 @@ enum kmalloc_cache_type {
NR_KMALLOC_TYPES
};
-#ifndef CONFIG_SLOB
extern struct kmem_cache *
kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1];
@@ -458,7 +444,6 @@ static __always_inline unsigned int __kmalloc_index(size_t size,
}
static_assert(PAGE_SHIFT <= 20);
#define kmalloc_index(s) __kmalloc_index(s, true)
-#endif /* !CONFIG_SLOB */
void *__kmalloc(size_t size, gfp_t flags) __assume_kmalloc_alignment __alloc_size(1);
@@ -487,10 +472,6 @@ void kmem_cache_free(struct kmem_cache *s, void *objp);
void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p);
int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, void **p);
-/*
- * Caller must not use kfree_bulk() on memory not originally allocated
- * by kmalloc(), because the SLOB allocator cannot handle this.
- */
static __always_inline void kfree_bulk(size_t size, void **p)
{
kmem_cache_free_bulk(NULL, size, p);
@@ -526,7 +507,7 @@ void *kmalloc_large_node(size_t size, gfp_t flags, int node) __assume_page_align
* to be at least to the size.
*
* The @flags argument may be one of the GFP flags defined at
- * include/linux/gfp.h and described at
+ * include/linux/gfp_types.h and described at
* :ref:`Documentation/core-api/mm-api.rst <mm-api-gfp-flags>`
*
* The recommended usage of the @flags is described at
@@ -567,7 +548,6 @@ void *kmalloc_large_node(size_t size, gfp_t flags, int node) __assume_page_align
* Try really hard to succeed the allocation but fail
* eventually.
*/
-#ifndef CONFIG_SLOB
static __always_inline __alloc_size(1) void *kmalloc(size_t size, gfp_t flags)
{
if (__builtin_constant_p(size) && size) {
@@ -583,17 +563,7 @@ static __always_inline __alloc_size(1) void *kmalloc(size_t size, gfp_t flags)
}
return __kmalloc(size, flags);
}
-#else
-static __always_inline __alloc_size(1) void *kmalloc(size_t size, gfp_t flags)
-{
- if (__builtin_constant_p(size) && size > KMALLOC_MAX_CACHE_SIZE)
- return kmalloc_large(size, flags);
-
- return __kmalloc(size, flags);
-}
-#endif
-#ifndef CONFIG_SLOB
static __always_inline __alloc_size(1) void *kmalloc_node(size_t size, gfp_t flags, int node)
{
if (__builtin_constant_p(size) && size) {
@@ -609,15 +579,6 @@ static __always_inline __alloc_size(1) void *kmalloc_node(size_t size, gfp_t fla
}
return __kmalloc_node(size, flags, node);
}
-#else
-static __always_inline __alloc_size(1) void *kmalloc_node(size_t size, gfp_t flags, int node)
-{
- if (__builtin_constant_p(size) && size > KMALLOC_MAX_CACHE_SIZE)
- return kmalloc_large_node(size, flags, node);
-
- return __kmalloc_node(size, flags, node);
-}
-#endif
/**
* kmalloc_array - allocate memory for an array.
diff --git a/init/Kconfig b/init/Kconfig
index 04acc3f80538..c9ec6e8e4d5d 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -945,7 +945,7 @@ config MEMCG
config MEMCG_KMEM
bool
- depends on MEMCG && !SLOB
+ depends on MEMCG
default y
config BLK_CGROUP
diff --git a/kernel/configs/tiny.config b/kernel/configs/tiny.config
index c2f9c912df1c..144b2bd86b14 100644
--- a/kernel/configs/tiny.config
+++ b/kernel/configs/tiny.config
@@ -7,6 +7,5 @@ CONFIG_KERNEL_XZ=y
# CONFIG_KERNEL_LZO is not set
# CONFIG_KERNEL_LZ4 is not set
# CONFIG_SLAB is not set
-# CONFIG_SLOB_DEPRECATED is not set
CONFIG_SLUB=y
CONFIG_SLUB_TINY=y
diff --git a/mm/Kconfig b/mm/Kconfig
index ebfe5796adf8..9c40844b7bc9 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -238,30 +238,8 @@ config SLUB
and has enhanced diagnostics. SLUB is the default choice for
a slab allocator.
-config SLOB_DEPRECATED
- depends on EXPERT
- bool "SLOB (Simple Allocator - DEPRECATED)"
- depends on !PREEMPT_RT
- help
- Deprecated and scheduled for removal in a few cycles. SLUB
- recommended as replacement. CONFIG_SLUB_TINY can be considered
- on systems with 16MB or less RAM.
-
- If you need SLOB to stay, please contact linux-mm@kvack.org and
- people listed in the SLAB ALLOCATOR section of MAINTAINERS file,
- with your use case.
-
- SLOB replaces the stock allocator with a drastically simpler
- allocator. SLOB is generally more space efficient but
- does not perform as well on large systems.
-
endchoice
-config SLOB
- bool
- default y
- depends on SLOB_DEPRECATED
-
config SLUB_TINY
bool "Configure SLUB for minimal memory footprint"
depends on SLUB && EXPERT
diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug
index c3547a373c9c..59c83ad976f7 100644
--- a/mm/Kconfig.debug
+++ b/mm/Kconfig.debug
@@ -60,9 +60,9 @@ config SLUB_DEBUG
select STACKDEPOT if STACKTRACE_SUPPORT
help
SLUB has extensive debug support features. Disabling these can
- result in significant savings in code size. This also disables
- SLUB sysfs support. /sys/slab will not exist and there will be
- no support for cache validation etc.
+ result in significant savings in code size. While /sys/kernel/slab
+ will still exist (with SYSFS enabled), it will not provide e.g. cache
+ validation.
config SLUB_DEBUG_ON
bool "SLUB debugging on by default"
diff --git a/mm/Makefile b/mm/Makefile
index 8e105e5b3e29..e347958fc6b2 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -22,7 +22,6 @@ KCSAN_INSTRUMENT_BARRIERS := y
# flaky coverage that is not a function of syscall inputs. E.g. slab is out of
# free pages, or a task is migrated between nodes.
KCOV_INSTRUMENT_slab_common.o := n
-KCOV_INSTRUMENT_slob.o := n
KCOV_INSTRUMENT_slab.o := n
KCOV_INSTRUMENT_slub.o := n
KCOV_INSTRUMENT_page_alloc.o := n
@@ -81,7 +80,6 @@ obj-$(CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP) += hugetlb_vmemmap.o
obj-$(CONFIG_NUMA) += mempolicy.o
obj-$(CONFIG_SPARSEMEM) += sparse.o
obj-$(CONFIG_SPARSEMEM_VMEMMAP) += sparse-vmemmap.o
-obj-$(CONFIG_SLOB) += slob.o
obj-$(CONFIG_MMU_NOTIFIER) += mmu_notifier.o
obj-$(CONFIG_KSM) += ksm.o
obj-$(CONFIG_PAGE_POISONING) += page_poison.o
diff --git a/mm/slab.h b/mm/slab.h
index 43966aa5fadf..399966b3ce52 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -51,14 +51,6 @@ struct slab {
};
unsigned int __unused;
-#elif defined(CONFIG_SLOB)
-
- struct list_head slab_list;
- void *__unused_1;
- void *freelist; /* first free block */
- long units;
- unsigned int __unused_2;
-
#else
#error "Unexpected slab allocator configured"
#endif
@@ -72,11 +64,7 @@ struct slab {
#define SLAB_MATCH(pg, sl) \
static_assert(offsetof(struct page, pg) == offsetof(struct slab, sl))
SLAB_MATCH(flags, __page_flags);
-#ifndef CONFIG_SLOB
SLAB_MATCH(compound_head, slab_cache); /* Ensure bit 0 is clear */
-#else
-SLAB_MATCH(compound_head, slab_list); /* Ensure bit 0 is clear */
-#endif
SLAB_MATCH(_refcount, __page_refcount);
#ifdef CONFIG_MEMCG
SLAB_MATCH(memcg_data, memcg_data);
@@ -200,31 +188,6 @@ static inline size_t slab_size(const struct slab *slab)
return PAGE_SIZE << slab_order(slab);
}
-#ifdef CONFIG_SLOB
-/*
- * Common fields provided in kmem_cache by all slab allocators
- * This struct is either used directly by the allocator (SLOB)
- * or the allocator must include definitions for all fields
- * provided in kmem_cache_common in their definition of kmem_cache.
- *
- * Once we can do anonymous structs (C11 standard) we could put a
- * anonymous struct definition in these allocators so that the
- * separate allocations in the kmem_cache structure of SLAB and
- * SLUB is no longer needed.
- */
-struct kmem_cache {
- unsigned int object_size;/* The original size of the object */
- unsigned int size; /* The aligned/padded/added on size */
- unsigned int align; /* Alignment as calculated */
- slab_flags_t flags; /* Active flags on the slab */
- const char *name; /* Slab name for sysfs */
- int refcount; /* Use counter */
- void (*ctor)(void *); /* Called on object slot creation */
- struct list_head list; /* List of all slab caches on the system */
-};
-
-#endif /* CONFIG_SLOB */
-
#ifdef CONFIG_SLAB
#include <linux/slab_def.h>
#endif
@@ -274,7 +237,6 @@ extern const struct kmalloc_info_struct {
unsigned int size;
} kmalloc_info[];
-#ifndef CONFIG_SLOB
/* Kmalloc array related functions */
void setup_kmalloc_cache_index_table(void);
void create_kmalloc_caches(slab_flags_t);
@@ -286,7 +248,6 @@ void *__kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags,
int node, size_t orig_size,
unsigned long caller);
void __kmem_cache_free(struct kmem_cache *s, void *x, unsigned long caller);
-#endif
gfp_t kmalloc_fix_flags(gfp_t flags);
@@ -303,33 +264,16 @@ extern void create_boot_cache(struct kmem_cache *, const char *name,
int slab_unmergeable(struct kmem_cache *s);
struct kmem_cache *find_mergeable(unsigned size, unsigned align,
slab_flags_t flags, const char *name, void (*ctor)(void *));
-#ifndef CONFIG_SLOB
struct kmem_cache *
__kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
slab_flags_t flags, void (*ctor)(void *));
slab_flags_t kmem_cache_flags(unsigned int object_size,
slab_flags_t flags, const char *name);
-#else
-static inline struct kmem_cache *
-__kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
- slab_flags_t flags, void (*ctor)(void *))
-{ return NULL; }
-
-static inline slab_flags_t kmem_cache_flags(unsigned int object_size,
- slab_flags_t flags, const char *name)
-{
- return flags;
-}
-#endif
static inline bool is_kmalloc_cache(struct kmem_cache *s)
{
-#ifndef CONFIG_SLOB
return (s->flags & SLAB_KMALLOC);
-#else
- return false;
-#endif
}
/* Legal flag mask for kmem_cache_create(), for various configurations */
@@ -634,7 +578,6 @@ static inline void memcg_slab_free_hook(struct kmem_cache *s, struct slab *slab,
}
#endif /* CONFIG_MEMCG_KMEM */
-#ifndef CONFIG_SLOB
static inline struct kmem_cache *virt_to_cache(const void *obj)
{
struct slab *slab;
@@ -684,8 +627,6 @@ static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
void free_large_kmalloc(struct folio *folio, void *object);
-#endif /* CONFIG_SLOB */
-
size_t __ksize(const void *objp);
static inline size_t slab_ksize(const struct kmem_cache *s)
@@ -777,7 +718,6 @@ static inline void slab_post_alloc_hook(struct kmem_cache *s,
memcg_slab_post_alloc_hook(s, objcg, flags, size, p);
}
-#ifndef CONFIG_SLOB
/*
* The slab lists for all objects.
*/
@@ -824,7 +764,6 @@ static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
for (__node = 0; __node < nr_node_ids; __node++) \
if ((__n = get_node(__s, __node)))
-#endif
#if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG)
void dump_unreclaimable_slab(void);
diff --git a/mm/slab_common.c b/mm/slab_common.c
index bf4e777cfe90..607249785c07 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -625,7 +625,6 @@ void kmem_dump_obj(void *object)
EXPORT_SYMBOL_GPL(kmem_dump_obj);
#endif
-#ifndef CONFIG_SLOB
/* Create a cache during boot when no slab services are available yet */
void __init create_boot_cache(struct kmem_cache *s, const char *name,
unsigned int size, slab_flags_t flags,
@@ -990,12 +989,9 @@ EXPORT_SYMBOL(__kmalloc_node_track_caller);
/**
* kfree - free previously allocated memory
- * @object: pointer returned by kmalloc.
+ * @object: pointer returned by kmalloc() or kmem_cache_alloc()
*
* If @object is NULL, no operation is performed.
- *
- * Don't free memory not originally allocated by kmalloc()
- * or you will run into trouble.
*/
void kfree(const void *object)
{
@@ -1079,7 +1075,6 @@ void *kmalloc_node_trace(struct kmem_cache *s, gfp_t gfpflags,
return ret;
}
EXPORT_SYMBOL(kmalloc_node_trace);
-#endif /* !CONFIG_SLOB */
gfp_t kmalloc_fix_flags(gfp_t flags)
{
diff --git a/mm/slob.c b/mm/slob.c
deleted file mode 100644
index fe567fcfa3a3..000000000000
--- a/mm/slob.c
+++ /dev/null
@@ -1,757 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * SLOB Allocator: Simple List Of Blocks
- *
- * Matt Mackall <mpm@selenic.com> 12/30/03
- *
- * NUMA support by Paul Mundt, 2007.
- *
- * How SLOB works:
- *
- * The core of SLOB is a traditional K&R style heap allocator, with
- * support for returning aligned objects. The granularity of this
- * allocator is as little as 2 bytes, however typically most architectures
- * will require 4 bytes on 32-bit and 8 bytes on 64-bit.
- *
- * The slob heap is a set of linked list of pages from alloc_pages(),
- * and within each page, there is a singly-linked list of free blocks
- * (slob_t). The heap is grown on demand. To reduce fragmentation,
- * heap pages are segregated into three lists, with objects less than
- * 256 bytes, objects less than 1024 bytes, and all other objects.
- *
- * Allocation from heap involves first searching for a page with
- * sufficient free blocks (using a next-fit-like approach) followed by
- * a first-fit scan of the page. Deallocation inserts objects back
- * into the free list in address order, so this is effectively an
- * address-ordered first fit.
- *
- * Above this is an implementation of kmalloc/kfree. Blocks returned
- * from kmalloc are prepended with a 4-byte header with the kmalloc size.
- * If kmalloc is asked for objects of PAGE_SIZE or larger, it calls
- * alloc_pages() directly, allocating compound pages so the page order
- * does not have to be separately tracked.
- * These objects are detected in kfree() because folio_test_slab()
- * is false for them.
- *
- * SLAB is emulated on top of SLOB by simply calling constructors and
- * destructors for every SLAB allocation. Objects are returned with the
- * 4-byte alignment unless the SLAB_HWCACHE_ALIGN flag is set, in which
- * case the low-level allocator will fragment blocks to create the proper
- * alignment. Again, objects of page-size or greater are allocated by
- * calling alloc_pages(). As SLAB objects know their size, no separate
- * size bookkeeping is necessary and there is essentially no allocation
- * space overhead, and compound pages aren't needed for multi-page
- * allocations.
- *
- * NUMA support in SLOB is fairly simplistic, pushing most of the real
- * logic down to the page allocator, and simply doing the node accounting
- * on the upper levels. In the event that a node id is explicitly
- * provided, __alloc_pages_node() with the specified node id is used
- * instead. The common case (or when the node id isn't explicitly provided)
- * will default to the current node, as per numa_node_id().
- *
- * Node aware pages are still inserted in to the global freelist, and
- * these are scanned for by matching against the node id encoded in the
- * page flags. As a result, block allocations that can be satisfied from
- * the freelist will only be done so on pages residing on the same node,
- * in order to prevent random node placement.
- */
-
-#include <linux/kernel.h>
-#include <linux/slab.h>
-
-#include <linux/mm.h>
-#include <linux/swap.h> /* struct reclaim_state */
-#include <linux/cache.h>
-#include <linux/init.h>
-#include <linux/export.h>
-#include <linux/rcupdate.h>
-#include <linux/list.h>
-#include <linux/kmemleak.h>
-
-#include <trace/events/kmem.h>
-
-#include <linux/atomic.h>
-
-#include "slab.h"
-/*
- * slob_block has a field 'units', which indicates size of block if +ve,
- * or offset of next block if -ve (in SLOB_UNITs).
- *
- * Free blocks of size 1 unit simply contain the offset of the next block.
- * Those with larger size contain their size in the first SLOB_UNIT of
- * memory, and the offset of the next free block in the second SLOB_UNIT.
- */
-#if PAGE_SIZE <= (32767 * 2)
-typedef s16 slobidx_t;
-#else
-typedef s32 slobidx_t;
-#endif
-
-struct slob_block {
- slobidx_t units;
-};
-typedef struct slob_block slob_t;
-
-/*
- * All partially free slob pages go on these lists.
- */
-#define SLOB_BREAK1 256
-#define SLOB_BREAK2 1024
-static LIST_HEAD(free_slob_small);
-static LIST_HEAD(free_slob_medium);
-static LIST_HEAD(free_slob_large);
-
-/*
- * slob_page_free: true for pages on free_slob_pages list.
- */
-static inline int slob_page_free(struct slab *slab)
-{
- return PageSlobFree(slab_page(slab));
-}
-
-static void set_slob_page_free(struct slab *slab, struct list_head *list)
-{
- list_add(&slab->slab_list, list);
- __SetPageSlobFree(slab_page(slab));
-}
-
-static inline void clear_slob_page_free(struct slab *slab)
-{
- list_del(&slab->slab_list);
- __ClearPageSlobFree(slab_page(slab));
-}
-
-#define SLOB_UNIT sizeof(slob_t)
-#define SLOB_UNITS(size) DIV_ROUND_UP(size, SLOB_UNIT)
-
-/*
- * struct slob_rcu is inserted at the tail of allocated slob blocks, which
- * were created with a SLAB_TYPESAFE_BY_RCU slab. slob_rcu is used to free
- * the block using call_rcu.
- */
-struct slob_rcu {
- struct rcu_head head;
- int size;
-};
-
-/*
- * slob_lock protects all slob allocator structures.
- */
-static DEFINE_SPINLOCK(slob_lock);
-
-/*
- * Encode the given size and next info into a free slob block s.
- */
-static void set_slob(slob_t *s, slobidx_t size, slob_t *next)
-{
- slob_t *base = (slob_t *)((unsigned long)s & PAGE_MASK);
- slobidx_t offset = next - base;
-
- if (size > 1) {
- s[0].units = size;
- s[1].units = offset;
- } else
- s[0].units = -offset;
-}
-
-/*
- * Return the size of a slob block.
- */
-static slobidx_t slob_units(slob_t *s)
-{
- if (s->units > 0)
- return s->units;
- return 1;
-}
-
-/*
- * Return the next free slob block pointer after this one.
- */
-static slob_t *slob_next(slob_t *s)
-{
- slob_t *base = (slob_t *)((unsigned long)s & PAGE_MASK);
- slobidx_t next;
-
- if (s[0].units < 0)
- next = -s[0].units;
- else
- next = s[1].units;
- return base+next;
-}
-
-/*
- * Returns true if s is the last free block in its page.
- */
-static int slob_last(slob_t *s)
-{
- return !((unsigned long)slob_next(s) & ~PAGE_MASK);
-}
-
-static void *slob_new_pages(gfp_t gfp, int order, int node)
-{
- struct page *page;
-
-#ifdef CONFIG_NUMA
- if (node != NUMA_NO_NODE)
- page = __alloc_pages_node(node, gfp, order);
- else
-#endif
- page = alloc_pages(gfp, order);
-
- if (!page)
- return NULL;
-
- mod_node_page_state(page_pgdat(page), NR_SLAB_UNRECLAIMABLE_B,
- PAGE_SIZE << order);
- return page_address(page);
-}
-
-static void slob_free_pages(void *b, int order)
-{
- struct page *sp = virt_to_page(b);
-
- if (current->reclaim_state)
- current->reclaim_state->reclaimed_slab += 1 << order;
-
- mod_node_page_state(page_pgdat(sp), NR_SLAB_UNRECLAIMABLE_B,
- -(PAGE_SIZE << order));
- __free_pages(sp, order);
-}
-
-/*
- * slob_page_alloc() - Allocate a slob block within a given slob_page sp.
- * @sp: Page to look in.
- * @size: Size of the allocation.
- * @align: Allocation alignment.
- * @align_offset: Offset in the allocated block that will be aligned.
- * @page_removed_from_list: Return parameter.
- *
- * Tries to find a chunk of memory at least @size bytes big within @page.
- *
- * Return: Pointer to memory if allocated, %NULL otherwise. If the
- * allocation fills up @page then the page is removed from the
- * freelist, in this case @page_removed_from_list will be set to
- * true (set to false otherwise).
- */
-static void *slob_page_alloc(struct slab *sp, size_t size, int align,
- int align_offset, bool *page_removed_from_list)
-{
- slob_t *prev, *cur, *aligned = NULL;
- int delta = 0, units = SLOB_UNITS(size);
-
- *page_removed_from_list = false;
- for (prev = NULL, cur = sp->freelist; ; prev = cur, cur = slob_next(cur)) {
- slobidx_t avail = slob_units(cur);
-
- /*
- * 'aligned' will hold the address of the slob block so that the
- * address 'aligned'+'align_offset' is aligned according to the
- * 'align' parameter. This is for kmalloc() which prepends the
- * allocated block with its size, so that the block itself is
- * aligned when needed.
- */
- if (align) {
- aligned = (slob_t *)
- (ALIGN((unsigned long)cur + align_offset, align)
- - align_offset);
- delta = aligned - cur;
- }
- if (avail >= units + delta) { /* room enough? */
- slob_t *next;
-
- if (delta) { /* need to fragment head to align? */
- next = slob_next(cur);
- set_slob(aligned, avail - delta, next);
- set_slob(cur, delta, aligned);
- prev = cur;
- cur = aligned;
- avail = slob_units(cur);
- }
-
- next = slob_next(cur);
- if (avail == units) { /* exact fit? unlink. */
- if (prev)
- set_slob(prev, slob_units(prev), next);
- else
- sp->freelist = next;
- } else { /* fragment */
- if (prev)
- set_slob(prev, slob_units(prev), cur + units);
- else
- sp->freelist = cur + units;
- set_slob(cur + units, avail - units, next);
- }
-
- sp->units -= units;
- if (!sp->units) {
- clear_slob_page_free(sp);
- *page_removed_from_list = true;
- }
- return cur;
- }
- if (slob_last(cur))
- return NULL;
- }
-}
-
-/*
- * slob_alloc: entry point into the slob allocator.
- */
-static void *slob_alloc(size_t size, gfp_t gfp, int align, int node,
- int align_offset)
-{
- struct folio *folio;
- struct slab *sp;
- struct list_head *slob_list;
- slob_t *b = NULL;
- unsigned long flags;
- bool _unused;
-
- if (size < SLOB_BREAK1)
- slob_list = &free_slob_small;
- else if (size < SLOB_BREAK2)
- slob_list = &free_slob_medium;
- else
- slob_list = &free_slob_large;
-
- spin_lock_irqsave(&slob_lock, flags);
- /* Iterate through each partially free page, try to find room */
- list_for_each_entry(sp, slob_list, slab_list) {
- bool page_removed_from_list = false;
-#ifdef CONFIG_NUMA
- /*
- * If there's a node specification, search for a partial
- * page with a matching node id in the freelist.
- */
- if (node != NUMA_NO_NODE && slab_nid(sp) != node)
- continue;
-#endif
- /* Enough room on this page? */
- if (sp->units < SLOB_UNITS(size))
- continue;
-
- b = slob_page_alloc(sp, size, align, align_offset, &page_removed_from_list);
- if (!b)
- continue;
-
- /*
- * If slob_page_alloc() removed sp from the list then we
- * cannot call list functions on sp. If so allocation
- * did not fragment the page anyway so optimisation is
- * unnecessary.
- */
- if (!page_removed_from_list) {
- /*
- * Improve fragment distribution and reduce our average
- * search time by starting our next search here. (see
- * Knuth vol 1, sec 2.5, pg 449)
- */
- if (!list_is_first(&sp->slab_list, slob_list))
- list_rotate_to_front(&sp->slab_list, slob_list);
- }
- break;
- }
- spin_unlock_irqrestore(&slob_lock, flags);
-
- /* Not enough space: must allocate a new page */
- if (!b) {
- b = slob_new_pages(gfp & ~__GFP_ZERO, 0, node);
- if (!b)
- return NULL;
- folio = virt_to_folio(b);
- __folio_set_slab(folio);
- sp = folio_slab(folio);
-
- spin_lock_irqsave(&slob_lock, flags);
- sp->units = SLOB_UNITS(PAGE_SIZE);
- sp->freelist = b;
- 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, align_offset, &_unused);
- BUG_ON(!b);
- spin_unlock_irqrestore(&slob_lock, flags);
- }
- if (unlikely(gfp & __GFP_ZERO))
- memset(b, 0, size);
- return b;
-}
-
-/*
- * slob_free: entry point into the slob allocator.
- */
-static void slob_free(void *block, int size)
-{
- struct slab *sp;
- slob_t *prev, *next, *b = (slob_t *)block;
- slobidx_t units;
- unsigned long flags;
- struct list_head *slob_list;
-
- if (unlikely(ZERO_OR_NULL_PTR(block)))
- return;
- BUG_ON(!size);
-
- sp = virt_to_slab(block);
- units = SLOB_UNITS(size);
-
- spin_lock_irqsave(&slob_lock, flags);
-
- if (sp->units + units == SLOB_UNITS(PAGE_SIZE)) {
- /* Go directly to page allocator. Do not pass slob allocator */
- if (slob_page_free(sp))
- clear_slob_page_free(sp);
- spin_unlock_irqrestore(&slob_lock, flags);
- __folio_clear_slab(slab_folio(sp));
- slob_free_pages(b, 0);
- return;
- }
-
- if (!slob_page_free(sp)) {
- /* This slob page is about to become partially free. Easy! */
- sp->units = units;
- sp->freelist = b;
- set_slob(b, units,
- (void *)((unsigned long)(b +
- SLOB_UNITS(PAGE_SIZE)) & PAGE_MASK));
- if (size < SLOB_BREAK1)
- slob_list = &free_slob_small;
- else if (size < SLOB_BREAK2)
- slob_list = &free_slob_medium;
- else
- slob_list = &free_slob_large;
- set_slob_page_free(sp, slob_list);
- goto out;
- }
-
- /*
- * Otherwise the page is already partially free, so find reinsertion
- * point.
- */
- sp->units += units;
-
- if (b < (slob_t *)sp->freelist) {
- if (b + units == sp->freelist) {
- units += slob_units(sp->freelist);
- sp->freelist = slob_next(sp->freelist);
- }
- set_slob(b, units, sp->freelist);
- sp->freelist = b;
- } else {
- prev = sp->freelist;
- next = slob_next(prev);
- while (b > next) {
- prev = next;
- next = slob_next(prev);
- }
-
- if (!slob_last(prev) && b + units == next) {
- units += slob_units(next);
- set_slob(b, units, slob_next(next));
- } else
- set_slob(b, units, next);
-
- if (prev + slob_units(prev) == b) {
- units = slob_units(b) + slob_units(prev);
- set_slob(prev, units, slob_next(b));
- } else
- set_slob(prev, slob_units(prev), b);
- }
-out:
- spin_unlock_irqrestore(&slob_lock, flags);
-}
-
-#ifdef CONFIG_PRINTK
-void __kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab)
-{
- kpp->kp_ptr = object;
- kpp->kp_slab = slab;
-}
-#endif
-
-/*
- * End of slob allocator proper. Begin kmem_cache_alloc and kmalloc frontend.
- */
-
-static __always_inline void *
-__do_kmalloc_node(size_t size, gfp_t gfp, int node, unsigned long caller)
-{
- unsigned int *m;
- unsigned int minalign;
- void *ret;
-
- minalign = max_t(unsigned int, ARCH_KMALLOC_MINALIGN,
- arch_slab_minalign());
- gfp &= gfp_allowed_mask;
-
- might_alloc(gfp);
-
- if (size < PAGE_SIZE - minalign) {
- int align = minalign;
-
- /*
- * For power of two sizes, guarantee natural alignment for
- * kmalloc()'d objects.
- */
- if (is_power_of_2(size))
- align = max_t(unsigned int, minalign, size);
-
- if (!size)
- return ZERO_SIZE_PTR;
-
- m = slob_alloc(size + minalign, gfp, align, node, minalign);
-
- if (!m)
- return NULL;
- *m = size;
- ret = (void *)m + minalign;
-
- trace_kmalloc(caller, ret, size, size + minalign, gfp, node);
- } else {
- unsigned int order = get_order(size);
-
- if (likely(order))
- gfp |= __GFP_COMP;
- ret = slob_new_pages(gfp, order, node);
-
- trace_kmalloc(caller, ret, size, PAGE_SIZE << order, gfp, node);
- }
-
- kmemleak_alloc(ret, size, 1, gfp);
- return ret;
-}
-
-void *__kmalloc(size_t size, gfp_t gfp)
-{
- return __do_kmalloc_node(size, gfp, NUMA_NO_NODE, _RET_IP_);
-}
-EXPORT_SYMBOL(__kmalloc);
-
-void *__kmalloc_node_track_caller(size_t size, gfp_t gfp,
- int node, unsigned long caller)
-{
- return __do_kmalloc_node(size, gfp, node, caller);
-}
-EXPORT_SYMBOL(__kmalloc_node_track_caller);
-
-void kfree(const void *block)
-{
- struct folio *sp;
-
- trace_kfree(_RET_IP_, block);
-
- if (unlikely(ZERO_OR_NULL_PTR(block)))
- return;
- kmemleak_free(block);
-
- sp = virt_to_folio(block);
- if (folio_test_slab(sp)) {
- unsigned int align = max_t(unsigned int,
- ARCH_KMALLOC_MINALIGN,
- arch_slab_minalign());
- unsigned int *m = (unsigned int *)(block - align);
-
- slob_free(m, *m + align);
- } else {
- unsigned int order = folio_order(sp);
-
- mod_node_page_state(folio_pgdat(sp), NR_SLAB_UNRECLAIMABLE_B,
- -(PAGE_SIZE << order));
- __free_pages(folio_page(sp, 0), order);
-
- }
-}
-EXPORT_SYMBOL(kfree);
-
-size_t kmalloc_size_roundup(size_t size)
-{
- /* Short-circuit the 0 size case. */
- if (unlikely(size == 0))
- return 0;
- /* Short-circuit saturated "too-large" case. */
- if (unlikely(size == SIZE_MAX))
- return SIZE_MAX;
-
- return ALIGN(size, ARCH_KMALLOC_MINALIGN);
-}
-
-EXPORT_SYMBOL(kmalloc_size_roundup);
-
-/* can't use ksize for kmem_cache_alloc memory, only kmalloc */
-size_t __ksize(const void *block)
-{
- struct folio *folio;
- unsigned int align;
- unsigned int *m;
-
- BUG_ON(!block);
- if (unlikely(block == ZERO_SIZE_PTR))
- return 0;
-
- folio = virt_to_folio(block);
- if (unlikely(!folio_test_slab(folio)))
- return folio_size(folio);
-
- align = max_t(unsigned int, ARCH_KMALLOC_MINALIGN,
- arch_slab_minalign());
- m = (unsigned int *)(block - align);
- return SLOB_UNITS(*m) * SLOB_UNIT;
-}
-
-int __kmem_cache_create(struct kmem_cache *c, slab_flags_t flags)
-{
- if (flags & SLAB_TYPESAFE_BY_RCU) {
- /* leave room for rcu footer at the end of object */
- c->size += sizeof(struct slob_rcu);
- }
-
- /* Actual size allocated */
- c->size = SLOB_UNITS(c->size) * SLOB_UNIT;
- c->flags = flags;
- return 0;
-}
-
-static void *slob_alloc_node(struct kmem_cache *c, gfp_t flags, int node)
-{
- void *b;
-
- flags &= gfp_allowed_mask;
-
- might_alloc(flags);
-
- if (c->size < PAGE_SIZE) {
- b = slob_alloc(c->size, flags, c->align, node, 0);
- trace_kmem_cache_alloc(_RET_IP_, b, c, flags, node);
- } else {
- b = slob_new_pages(flags, get_order(c->size), node);
- trace_kmem_cache_alloc(_RET_IP_, b, c, flags, node);
- }
-
- if (b && c->ctor) {
- WARN_ON_ONCE(flags & __GFP_ZERO);
- c->ctor(b);
- }
-
- kmemleak_alloc_recursive(b, c->size, 1, c->flags, flags);
- return b;
-}
-
-void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
-{
- return slob_alloc_node(cachep, flags, NUMA_NO_NODE);
-}
-EXPORT_SYMBOL(kmem_cache_alloc);
-
-
-void *kmem_cache_alloc_lru(struct kmem_cache *cachep, struct list_lru *lru, gfp_t flags)
-{
- return slob_alloc_node(cachep, flags, NUMA_NO_NODE);
-}
-EXPORT_SYMBOL(kmem_cache_alloc_lru);
-
-void *__kmalloc_node(size_t size, gfp_t gfp, int node)
-{
- return __do_kmalloc_node(size, gfp, node, _RET_IP_);
-}
-EXPORT_SYMBOL(__kmalloc_node);
-
-void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t gfp, int node)
-{
- return slob_alloc_node(cachep, gfp, node);
-}
-EXPORT_SYMBOL(kmem_cache_alloc_node);
-
-static void __kmem_cache_free(void *b, int size)
-{
- if (size < PAGE_SIZE)
- slob_free(b, size);
- else
- slob_free_pages(b, get_order(size));
-}
-
-static void kmem_rcu_free(struct rcu_head *head)
-{
- struct slob_rcu *slob_rcu = (struct slob_rcu *)head;
- void *b = (void *)slob_rcu - (slob_rcu->size - sizeof(struct slob_rcu));
-
- __kmem_cache_free(b, slob_rcu->size);
-}
-
-void kmem_cache_free(struct kmem_cache *c, void *b)
-{
- kmemleak_free_recursive(b, c->flags);
- trace_kmem_cache_free(_RET_IP_, b, c);
- if (unlikely(c->flags & SLAB_TYPESAFE_BY_RCU)) {
- struct slob_rcu *slob_rcu;
- slob_rcu = b + (c->size - sizeof(struct slob_rcu));
- slob_rcu->size = c->size;
- call_rcu(&slob_rcu->head, kmem_rcu_free);
- } else {
- __kmem_cache_free(b, c->size);
- }
-}
-EXPORT_SYMBOL(kmem_cache_free);
-
-void kmem_cache_free_bulk(struct kmem_cache *s, size_t nr, void **p)
-{
- size_t i;
-
- for (i = 0; i < nr; i++) {
- if (s)
- kmem_cache_free(s, p[i]);
- else
- kfree(p[i]);
- }
-}
-EXPORT_SYMBOL(kmem_cache_free_bulk);
-
-int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t nr,
- void **p)
-{
- size_t i;
-
- for (i = 0; i < nr; i++) {
- void *x = p[i] = kmem_cache_alloc(s, flags);
-
- if (!x) {
- kmem_cache_free_bulk(s, i, p);
- return 0;
- }
- }
- return i;
-}
-EXPORT_SYMBOL(kmem_cache_alloc_bulk);
-
-int __kmem_cache_shutdown(struct kmem_cache *c)
-{
- /* No way to check for remaining objects */
- return 0;
-}
-
-void __kmem_cache_release(struct kmem_cache *c)
-{
-}
-
-int __kmem_cache_shrink(struct kmem_cache *d)
-{
- return 0;
-}
-
-static struct kmem_cache kmem_cache_boot = {
- .name = "kmem_cache",
- .size = sizeof(struct kmem_cache),
- .flags = SLAB_PANIC,
- .align = ARCH_KMALLOC_MINALIGN,
-};
-
-void __init kmem_cache_init(void)
-{
- kmem_cache = &kmem_cache_boot;
- slab_state = UP;
-}
-
-void __init kmem_cache_init_late(void)
-{
- slab_state = FULL;
-}
diff --git a/mm/slub.c b/mm/slub.c
index 39327e98fce3..28ca576d988d 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -6059,7 +6059,7 @@ static const struct sysfs_ops slab_sysfs_ops = {
.store = slab_attr_store,
};
-static struct kobj_type slab_ktype = {
+static const struct kobj_type slab_ktype = {
.sysfs_ops = &slab_sysfs_ops,
.release = kmem_cache_release,
};
diff --git a/tools/mm/page-types.c b/tools/mm/page-types.c
index 381dcc00cb62..8d5595b6c59f 100644
--- a/tools/mm/page-types.c
+++ b/tools/mm/page-types.c
@@ -85,7 +85,6 @@
*/
#define KPF_ANON_EXCLUSIVE 47
#define KPF_READAHEAD 48
-#define KPF_SLOB_FREE 49
#define KPF_SLUB_FROZEN 50
#define KPF_SLUB_DEBUG 51
#define KPF_FILE 61
@@ -141,7 +140,6 @@ static const char * const page_flag_names[] = {
[KPF_ANON_EXCLUSIVE] = "d:anon_exclusive",
[KPF_READAHEAD] = "I:readahead",
- [KPF_SLOB_FREE] = "P:slob_free",
[KPF_SLUB_FROZEN] = "A:slub_frozen",
[KPF_SLUB_DEBUG] = "E:slub_debug",
@@ -478,10 +476,8 @@ static uint64_t expand_overloaded_flags(uint64_t flags, uint64_t pme)
if ((flags & BIT(ANON)) && (flags & BIT(MAPPEDTODISK)))
flags ^= BIT(MAPPEDTODISK) | BIT(ANON_EXCLUSIVE);
- /* SLOB/SLUB overload several page flags */
+ /* SLUB overloads several page flags */
if (flags & BIT(SLAB)) {
- if (flags & BIT(PRIVATE))
- flags ^= BIT(PRIVATE) | BIT(SLOB_FREE);
if (flags & BIT(ACTIVE))
flags ^= BIT(ACTIVE) | BIT(SLUB_FROZEN);
if (flags & BIT(ERROR))