Folks from non-slab subsystems are Cc'd only to patches affecting them, and this cover letter. Series also available in git, based on 5.16-rc6: https://git.kernel.org/pub/scm/linux/kernel/git/vbabka/linux.git/log/?h=slab-struct_slab-v4r2 The plan is to submit as pull request, the previous versions have been in linux-next since v2 early December. This v4 was in linux-next since Dec 22: https://lore.kernel.org/all/f3a83708-3f3c-a634-7bee-dcfcaaa7f36e@xxxxxxx/ I planned to post it on mailing list for any final review in January, so this is it. Added only reviewed/tested tags from Hyeonggon Yoo meahwhile. Changes from v3: https://lore.kernel.org/all/4c3dfdfa-2e19-a9a7-7945-3d75bc87ca05@xxxxxxx/ - rebase to 5.16-rc6 to avoid a conflict with mainline - collect acks/reviews/tested-by from Johannes, Roman, Hyeonggon Yoo - thanks! - in patch "mm/slub: Convert detached_freelist to use a struct slab" renamed free_nonslab_page() to free_large_kmalloc() and use folio there, as suggested by Roman - in "mm/memcg: Convert slab objcgs from struct page to struct slab" change one caller of slab_objcgs_check() to slab_objcgs() as suggested by Johannes, realize the other caller should be also changed, and remove slab_objcgs_check() completely. Initial version from Matthew Wilcox: https://lore.kernel.org/all/20211004134650.4031813-1-willy@xxxxxxxxxxxxx/ LWN coverage of the above: https://lwn.net/Articles/871982/ This is originally an offshoot of the folio work by Matthew. One of the more complex parts of the struct page definition are the parts used by the slab allocators. It would be good for the MM in general if struct slab were its own data type, and it also helps to prevent tail pages from slipping in anywhere. As Matthew requested in his proof of concept series, I have taken over the development of this series, so it's a mix of patches from him (often modified by me) and my own. One big difference is the use of coccinelle to perform the relatively trivial parts of the conversions automatically and at once, instead of a larger number of smaller incremental reviewable steps. Thanks to Julia Lawall and Luis Chamberlain for all their help! Another notable difference is (based also on review feedback) I don't represent with a struct slab the large kmalloc allocations which are not really a slab, but use page allocator directly. When going from an object address to a struct slab, the code tests first folio slab flag, and only if it's set it converts to struct slab. This makes the struct slab type stronger. Finally, although Matthew's version didn't use any of the folio work, the initial support has been merged meanwhile so my version builds on top of it where appropriate. This eliminates some of the redundant compound_head() being performed e.g. when testing the slab flag. To sum up, after this series, struct page fields used by slab allocators are moved from struct page to a new struct slab, that uses the same physical storage. The availability of the fields is further distinguished by the selected slab allocator implementation. The advantages include: - Similar to folios, if the slab is of order > 0, struct slab always is guaranteed to be the head page. Additionally it's guaranteed to be an actual slab page, not a large kmalloc. This removes uncertainty and potential for bugs. - It's not possible to accidentally use fields of the slab implementation that's not configured. - Other subsystems cannot use slab's fields in struct page anymore (some existing non-slab usages had to be adjusted in this series), so slab implementations have more freedom in rearranging them in the struct slab. Hyeonggon Yoo (1): mm/slob: Remove unnecessary page_mapcount_reset() function call Matthew Wilcox (Oracle) (14): mm: Split slab into its own type mm: Convert [un]account_slab_page() to struct slab mm: Convert virt_to_cache() to use struct slab mm: Convert __ksize() to struct slab mm: Use struct slab in kmem_obj_info() mm: Convert check_heap_object() to use struct slab mm/slub: Convert detached_freelist to use a struct slab mm/slub: Convert kfree() to use a struct slab mm/slub: Convert print_page_info() to print_slab_info() mm/slub: Convert pfmemalloc_match() to take a struct slab mm/slob: Convert SLOB to use struct slab and struct folio mm/kasan: Convert to struct folio and struct slab zsmalloc: Stop using slab fields in struct page bootmem: Use page->index instead of page->freelist Vlastimil Babka (17): mm: add virt_to_folio() and folio_address() mm/slab: Dissolve slab_map_pages() in its caller mm/slub: Make object_err() static mm/slub: Convert __slab_lock() and __slab_unlock() to struct slab mm/slub: Convert alloc_slab_page() to return a struct slab mm/slub: Convert __free_slab() to use struct slab mm/slub: Convert most struct page to struct slab by spatch mm/slub: Finish struct page to struct slab conversion mm/slab: Convert kmem_getpages() and kmem_freepages() to struct slab mm/slab: Convert most struct page to struct slab by spatch mm/slab: Finish struct page to struct slab conversion mm: Convert struct page to struct slab in functions used by other subsystems mm/memcg: Convert slab objcgs from struct page to struct slab mm/kfence: Convert kfence_guarded_alloc() to struct slab mm/sl*b: Differentiate struct slab fields by sl*b implementations mm/slub: Simplify struct slab slabs field definition mm/slub: Define struct slab fields for CONFIG_SLUB_CPU_PARTIAL only when enabled arch/x86/mm/init_64.c | 2 +- include/linux/bootmem_info.h | 2 +- include/linux/kasan.h | 9 +- include/linux/memcontrol.h | 48 -- include/linux/mm.h | 12 + include/linux/mm_types.h | 10 +- include/linux/slab.h | 8 - include/linux/slab_def.h | 16 +- include/linux/slub_def.h | 29 +- mm/bootmem_info.c | 7 +- mm/kasan/common.c | 27 +- mm/kasan/generic.c | 8 +- mm/kasan/kasan.h | 1 + mm/kasan/quarantine.c | 2 +- mm/kasan/report.c | 13 +- mm/kasan/report_tags.c | 10 +- mm/kfence/core.c | 17 +- mm/kfence/kfence_test.c | 6 +- mm/memcontrol.c | 47 +- mm/slab.c | 456 +++++++------ mm/slab.h | 305 +++++++-- mm/slab_common.c | 14 +- mm/slob.c | 62 +- mm/slub.c | 1177 +++++++++++++++++----------------- mm/sparse.c | 2 +- mm/usercopy.c | 13 +- mm/zsmalloc.c | 18 +- 27 files changed, 1263 insertions(+), 1058 deletions(-) -- 2.34.1
