Merge tag 'slab-for-6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab

Pull slab updates from Vlastimil Babka:

 - SLUB: delayed freezing of CPU partial slabs (Chengming Zhou)

   Freezing is an operation involving double_cmpxchg() that makes a slab
   exclusive for a particular CPU. Chengming noticed that we use it also
   in situations where we are not yet installing the slab as the CPU
   slab, because freezing also indicates that the slab is not on the
   shared list. This results in redundant freeze/unfreeze operation and
   can be avoided by marking separately the shared list presence by
   reusing the PG_workingset flag.

   This approach neatly avoids the issues described in 9b1ea29
   ("Revert "mm, slub: consider rest of partial list if acquire_slab()
   fails"") as we can now grab a slab from the shared list in a quick
   and guaranteed way without the cmpxchg_double() operation that
   amplifies the lock contention and can fail.

   As a result, lkp has reported 34.2% improvement of
   stress-ng.rawudp.ops_per_sec

 - SLAB removal and SLUB cleanups (Vlastimil Babka)

   The SLAB allocator has been deprecated since 6.5 and nobody has
   objected so far. We agreed at LSF/MM to wait until the next LTS,
   which is 6.6, so we should be good to go now.

   This doesn't yet erase all traces of SLAB outside of mm/ so some dead
   code, comments or documentation remain, and will be cleaned up
   gradually (some series are already in the works).

   Removing the choice of allocators has already allowed to simplify and
   optimize the code wiring up the kmalloc APIs to the SLUB
   implementation.

* tag 'slab-for-6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab: (34 commits)
  mm/slub: free KFENCE objects in slab_free_hook()
  mm/slub: handle bulk and single object freeing separately
  mm/slub: introduce __kmem_cache_free_bulk() without free hooks
  mm/slub: fix bulk alloc and free stats
  mm/slub: optimize free fast path code layout
  mm/slub: optimize alloc fastpath code layout
  mm/slub: remove slab_alloc() and __kmem_cache_alloc_lru() wrappers
  mm/slab: move kmalloc() functions from slab_common.c to slub.c
  mm/slab: move kmalloc_slab() to mm/slab.h
  mm/slab: move kfree() from slab_common.c to slub.c
  mm/slab: move struct kmem_cache_node from slab.h to slub.c
  mm/slab: move memcg related functions from slab.h to slub.c
  mm/slab: move pre/post-alloc hooks from slab.h to slub.c
  mm/slab: consolidate includes in the internal mm/slab.h
  mm/slab: move the rest of slub_def.h to mm/slab.h
  mm/slab: move struct kmem_cache_cpu declaration to slub.c
  mm/slab: remove mm/slab.c and slab_def.h
  mm/mempool/dmapool: remove CONFIG_DEBUG_SLAB ifdefs
  mm/slab: remove CONFIG_SLAB code from slab common code
  cpu/hotplug: remove CPUHP_SLAB_PREPARE hooks
  ...

Author: torvalds

CREDITS

@@ -9,10 +9,6 @@
 			Linus
 ----------
 
-N: Matt Mackal
-E: mpm@selenic.com
-D: SLOB slab allocator
-
 N: Matti Aarnio
 E: mea@nic.funet.fi
 D: Alpha systems hacking, IPv6 and other network related stuff
@@ -1572,6 +1568,10 @@ S: Ampferstr. 50 / 4
 S: 6020 Innsbruck
 S: Austria
 
+N: Mark Hemment
+E: markhe@nextd.demon.co.uk
+D: SLAB allocator implementation
+
 N: Richard Henderson
 E: rth@twiddle.net
 E: rth@cygnus.com
@@ -2445,6 +2445,10 @@ D: work on suspend-to-ram/disk, killing duplicates from ioctl32,
 D: Altera SoCFPGA and Nokia N900 support.
 S: Czech Republic
 
+N: Olivia Mackall
+E: olivia@selenic.com
+D: SLOB slab allocator
+
 N: Paul Mackerras
 E: paulus@samba.org
 D: PPP driver

Documentation/core-api/mm-api.rst

@@ -37,7 +37,7 @@ The Slab Cache
 .. kernel-doc:: include/linux/slab.h
    :internal:
 
-.. kernel-doc:: mm/slab.c
+.. kernel-doc:: mm/slub.c
    :export:
 
 .. kernel-doc:: mm/slab_common.c

arch/arm64/Kconfig

@@ -154,7 +154,7 @@ config ARM64
 	select HAVE_MOVE_PUD
 	select HAVE_PCI
 	select HAVE_ACPI_APEI if (ACPI && EFI)
-	select HAVE_ALIGNED_STRUCT_PAGE if SLUB
+	select HAVE_ALIGNED_STRUCT_PAGE
 	select HAVE_ARCH_AUDITSYSCALL
 	select HAVE_ARCH_BITREVERSE
 	select HAVE_ARCH_COMPILER_H

arch/s390/Kconfig

@@ -146,7 +146,7 @@ config S390
 	select GENERIC_TIME_VSYSCALL
 	select GENERIC_VDSO_TIME_NS
 	select GENERIC_IOREMAP if PCI
-	select HAVE_ALIGNED_STRUCT_PAGE if SLUB
+	select HAVE_ALIGNED_STRUCT_PAGE
 	select HAVE_ARCH_AUDITSYSCALL
 	select HAVE_ARCH_JUMP_LABEL
 	select HAVE_ARCH_JUMP_LABEL_RELATIVE

arch/x86/Kconfig

@@ -169,7 +169,7 @@ config X86
 	select HAS_IOPORT
 	select HAVE_ACPI_APEI			if ACPI
 	select HAVE_ACPI_APEI_NMI		if ACPI
-	select HAVE_ALIGNED_STRUCT_PAGE		if SLUB
+	select HAVE_ALIGNED_STRUCT_PAGE
 	select HAVE_ARCH_AUDITSYSCALL
 	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
 	select HAVE_ARCH_HUGE_VMALLOC		if X86_64

include/linux/cpuhotplug.h

@@ -104,7 +104,6 @@ enum cpuhp_state {
 	CPUHP_X2APIC_PREPARE,
 	CPUHP_SMPCFD_PREPARE,
 	CPUHP_RELAY_PREPARE,
-	CPUHP_SLAB_PREPARE,
 	CPUHP_MD_RAID5_PREPARE,
 	CPUHP_RCUTREE_PREP,
 	CPUHP_CPUIDLE_COUPLED_PREPARE,

include/linux/slab.h

@@ -24,7 +24,7 @@
 
 /*
  * Flags to pass to kmem_cache_create().
- * The ones marked DEBUG are only valid if CONFIG_DEBUG_SLAB is set.
+ * The ones marked DEBUG need CONFIG_SLUB_DEBUG enabled, otherwise are no-op
  */
 /* DEBUG: Perform (expensive) checks on alloc/free */
 #define SLAB_CONSISTENCY_CHECKS	((slab_flags_t __force)0x00000100U)
@@ -302,25 +302,15 @@ static inline unsigned int arch_slab_minalign(void)
  * Kmalloc array related definitions
  */
 
-#ifdef CONFIG_SLAB
 /*
- * SLAB and SLUB directly allocates requests fitting in to an order-1 page
+ * SLUB directly allocates requests fitting in to an order-1 page
  * (PAGE_SIZE*2).  Larger requests are passed to the page allocator.
  */
 #define KMALLOC_SHIFT_HIGH	(PAGE_SHIFT + 1)
 #define KMALLOC_SHIFT_MAX	(MAX_ORDER + PAGE_SHIFT)
 #ifndef KMALLOC_SHIFT_LOW
-#define KMALLOC_SHIFT_LOW	5
-#endif
-#endif
-
-#ifdef CONFIG_SLUB
-#define KMALLOC_SHIFT_HIGH	(PAGE_SHIFT + 1)
-#define KMALLOC_SHIFT_MAX	(MAX_ORDER + PAGE_SHIFT)
-#ifndef KMALLOC_SHIFT_LOW
 #define KMALLOC_SHIFT_LOW	3
 #endif
-#endif
 
 /* Maximum allocatable size */
 #define KMALLOC_MAX_SIZE	(1UL << KMALLOC_SHIFT_MAX)
@@ -788,12 +778,4 @@ size_t kmalloc_size_roundup(size_t size);
 
 void __init kmem_cache_init_late(void);
 
-#if defined(CONFIG_SMP) && defined(CONFIG_SLAB)
-int slab_prepare_cpu(unsigned int cpu);
-int slab_dead_cpu(unsigned int cpu);
-#else
-#define slab_prepare_cpu	NULL
-#define slab_dead_cpu		NULL
-#endif
-
 #endif	/* _LINUX_SLAB_H */