user/sven/linux.git/include/linux/slab.h, branch v6.2-rc5

Merge tag 'slab-for-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab

2022-12-12T17:13:06Z

Pull slab updates from Vlastimil Babka: - SLOB deprecation and SLUB_TINY The SLOB allocator adds maintenance burden and stands in the way of API improvements [1]. Deprecate it by renaming the config option (to make users notice) to CONFIG_SLOB_DEPRECATED with updated help text. SLUB should be used instead as SLAB will be the next on the removal list. Based on reports from a riscv k210 board with 8MB RAM, add a CONFIG_SLUB_TINY option to minimize SLUB's memory usage at the expense of scalability. This has resolved the k210 regression [2] so in case there are no others (that wouldn't be resolvable by further tweaks to SLUB_TINY) plan is to remove SLOB in a few cycles. Existing defconfigs with CONFIG_SLOB are converted to CONFIG_SLUB_TINY. - kmalloc() slub_debug redzone improvements A series from Feng Tang that builds on the tracking or requested size for kmalloc() allocations (for caches with debugging enabled) added in 6.1, to make redzone checks consider the requested size and not the rounded up one, in order to catch more subtle buffer overruns. Includes new slub_kunit test. - struct slab fields reordering to accomodate larger rcu_head RCU folks would like to grow rcu_head with debugging options, which breaks current struct slab layout's assumptions, so reorganize it to make this possible. - Miscellaneous improvements/fixes: - __alloc_size checking compiler workaround (Kees Cook) - Optimize and cleanup SLUB's sysfs init (Rasmus Villemoes) - Make SLAB compatible with PROVE_RAW_LOCK_NESTING (Jiri Kosina) - Correct SLUB's percpu allocation estimates (Baoquan He) - Re-enableS LUB's run-time failslab sysfs control (Alexander Atanasov) - Make tools/vm/slabinfo more user friendly when not run as root (Rong Tao) - Dead code removal in SLUB (Hyeonggon Yoo) * tag 'slab-for-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab: (31 commits) mm, slob: rename CONFIG_SLOB to CONFIG_SLOB_DEPRECATED mm, slub: don't aggressively inline with CONFIG_SLUB_TINY mm, slub: remove percpu slabs with CONFIG_SLUB_TINY mm, slub: split out allocations from pre/post hooks mm/slub, kunit: Add a test case for kmalloc redzone check mm/slub, kunit: add SLAB_SKIP_KFENCE flag for cache creation mm, slub: refactor free debug processing mm, slab: ignore SLAB_RECLAIM_ACCOUNT with CONFIG_SLUB_TINY mm, slub: don't create kmalloc-rcl caches with CONFIG_SLUB_TINY mm, slub: lower the default slub_max_order with CONFIG_SLUB_TINY mm, slub: retain no free slabs on partial list with CONFIG_SLUB_TINY mm, slub: disable SYSFS support with CONFIG_SLUB_TINY mm, slub: add CONFIG_SLUB_TINY mm, slab: ignore hardened usercopy parameters when disabled slab: Remove special-casing of const 0 size allocations slab: Clean up SLOB vs kmalloc() definition mm/sl[au]b: rearrange struct slab fields to allow larger rcu_head mm/migrate: make isolate_movable_page() skip slab pages mm/slab: move and adjust kernel-doc for kmem_cache_alloc mm/slub, percpu: correct the calculation of early percpu allocation size ...

Merge tag 'rcu.2022.12.02a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu

2022-12-12T15:47:15Z

Pull RCU updates from Paul McKenney: - Documentation updates. This is the second in a series from an ongoing review of the RCU documentation. - Miscellaneous fixes. - Introduce a default-off Kconfig option that depends on RCU_NOCB_CPU that, on CPUs mentioned in the nohz_full or rcu_nocbs boot-argument CPU lists, causes call_rcu() to introduce delays. These delays result in significant power savings on nearly idle Android and ChromeOS systems. These savings range from a few percent to more than ten percent. This series also includes several commits that change call_rcu() to a new call_rcu_hurry() function that avoids these delays in a few cases, for example, where timely wakeups are required. Several of these are outside of RCU and thus have acks and reviews from the relevant maintainers. - Create an srcu_read_lock_nmisafe() and an srcu_read_unlock_nmisafe() for architectures that support NMIs, but which do not provide NMI-safe this_cpu_inc(). These NMI-safe SRCU functions are required by the upcoming lockless printk() work by John Ogness et al. - Changes providing minor but important increases in torture test coverage for the new RCU polled-grace-period APIs. - Changes to torturescript that avoid redundant kernel builds, thus providing about a 30% speedup for the torture.sh acceptance test. * tag 'rcu.2022.12.02a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: (49 commits) net: devinet: Reduce refcount before grace period net: Use call_rcu_hurry() for dst_release() workqueue: Make queue_rcu_work() use call_rcu_hurry() percpu-refcount: Use call_rcu_hurry() for atomic switch scsi/scsi_error: Use call_rcu_hurry() instead of call_rcu() rcu/rcutorture: Use call_rcu_hurry() where needed rcu/rcuscale: Use call_rcu_hurry() for async reader test rcu/sync: Use call_rcu_hurry() instead of call_rcu rcuscale: Add laziness and kfree tests rcu: Shrinker for lazy rcu rcu: Refactor code a bit in rcu_nocb_do_flush_bypass() rcu: Make call_rcu() lazy to save power rcu: Implement lockdep_rcu_enabled for !CONFIG_DEBUG_LOCK_ALLOC srcu: Debug NMI safety even on archs that don't require it srcu: Explain the reason behind the read side critical section on GP start srcu: Warn when NMI-unsafe API is used in NMI arch/s390: Add ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option arch/loongarch: Add ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option rcu: Fix __this_cpu_read() lockdep warning in rcu_force_quiescent_state() rcu-tasks: Make grace-period-age message human-readable ...

Merge branch 'slub-tiny-v1r6' into slab/for-next

2022-11-30T23:14:00Z

Merge my series [1] to deprecate the SLOB allocator. - Renames CONFIG_SLOB to CONFIG_SLOB_DEPRECATED with deprecation notice. - The recommended replacement is CONFIG_SLUB, optionally with the new CONFIG_SLUB_TINY tweaks for systems with 16MB or less RAM. - Use cases that stopped working with CONFIG_SLUB_TINY instead of SLOB should be reported to linux-mm@kvack.org and slab maintainers, otherwise SLOB will be removed in few cycles. [1] https://lore.kernel.org/all/20221121171202.22080-1-vbabka@suse.cz/

mm, slab: ignore SLAB_RECLAIM_ACCOUNT with CONFIG_SLUB_TINY

2022-11-27T22:40:39Z

SLAB_RECLAIM_ACCOUNT caches allocate their slab pages with __GFP_RECLAIMABLE and can help against fragmentation by grouping pages by mobility, but on tiny systems mobility grouping is likely disabled anyway and ignoring SLAB_RECLAIM_ACCOUNT might instead lead to merging of caches that are made incompatible just by the flag. Thus with CONFIG_SLUB_TINY, make SLAB_RECLAIM_ACCOUNT ineffective. Signed-off-by: Vlastimil Babka Acked-by: Mike Rapoport Reviewed-by: Christoph Lameter

mm, slub: don't create kmalloc-rcl caches with CONFIG_SLUB_TINY

2022-11-27T22:39:02Z

Distinguishing kmalloc(__GFP_RECLAIMABLE) can help against fragmentation by grouping pages by mobility, but on tiny systems the extra memory overhead of separate set of kmalloc-rcl caches will probably be worse, and mobility grouping likely disabled anyway. Thus with CONFIG_SLUB_TINY, don't create kmalloc-rcl caches and use the regular ones. Signed-off-by: Vlastimil Babka Acked-by: Mike Rapoport Reviewed-by: Christoph Lameter

Merge branch 'slab/for-6.2/alloc_size' into slab/for-next

2022-11-21T09:37:36Z

Two patches from Kees Cook [1]: These patches work around a deficiency in GCC (>=11) and Clang (<16) where the __alloc_size attribute does not apply to inlines. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96503 This manifests as reduced overflow detection coverage for many allocation sites under CONFIG_FORTIFY_SOURCE=y, where the allocation size was not actually being propagated to __builtin_dynamic_object_size(). [1] https://lore.kernel.org/all/20221118034713.gonna.754-kees@kernel.org/

Merge branch 'slab/for-6.2/cleanups' into slab/for-next

2022-11-21T09:35:37Z

- Removal of dead code from deactivate_slab() by Hyeonggon Yoo. - Fix of BUILD_BUG_ON() for sufficient early percpu size by Baoquan He. - Make kmem_cache_alloc() kernel-doc less misleading, by myself.

slab: Remove special-casing of const 0 size allocations

2022-11-21T09:27:00Z

Passing a constant-0 size allocation into kmalloc() or kmalloc_node() does not need to be a fast-path operation, so the static return value can be removed entirely. This makes sure that all paths through the inlines result in a full extern function call, where __alloc_size() hints will actually be seen[1] by GCC. (A constant return value of 0 means the "0" allocation size won't be propagated by the inline.) [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96503 Cc: Vlastimil Babka Cc: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Cc: Andrew Morton Cc: Roman Gushchin Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: linux-mm@kvack.org Signed-off-by: Kees Cook Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by: Vlastimil Babka

slab: Clean up SLOB vs kmalloc() definition

2022-11-21T09:26:52Z

As already done for kmalloc_node(), clean up the #ifdef usage in the definition of kmalloc() so that the SLOB-only version is an entirely separate and much more readable function. Cc: Vlastimil Babka Cc: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Cc: Andrew Morton Cc: Roman Gushchin Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: linux-mm@kvack.org Signed-off-by: Kees Cook Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by: Vlastimil Babka

mm/slab: move and adjust kernel-doc for kmem_cache_alloc

2022-11-21T09:19:46Z

Alexander reports an issue with the kmem_cache_alloc() comment in mm/slab.c: > The current comment mentioned that the flags only matters if the > cache has no available objects. It's different for the __GFP_ZERO > flag which will ensure that the returned object is always zeroed > in any case. > I have the feeling I run into this question already two times if > the user need to zero the object or not, but the user does not need > to zero the object afterwards. However another use of __GFP_ZERO > and only zero the object if the cache has no available objects would > also make no sense. and suggests thus mentioning __GFP_ZERO as the exception. But on closer inspection, the part about flags being only relevant if cache has no available objects is misleading. The slab user has no reliable way to determine if there are available objects, and e.g. the might_sleep() debug check can be performed even if objects are available, so passing correct flags given the allocation context always matters. Thus remove that sentence completely, and while at it, move the comment to from SLAB-specific mm/slab.c to the common include/linux/slab.h The comment otherwise refers flags description for kmalloc(), so add __GFP_ZERO comment there and remove a very misleading GFP_HIGHUSER (not applicable to slab) description from there. Mention kzalloc() and kmem_cache_zalloc() shortcuts. Reported-by: Alexander Aring Link: https://lore.kernel.org/all/20221011145413.8025-1-aahringo@redhat.com/ Signed-off-by: Vlastimil Babka