From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 74DC84D8D1 for ; Sat, 7 Dec 2024 04:29:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733545773; cv=none; b=L4i+E7BlGg0yBH3wrHLllQbSFMTH0a15HIzb6wDNv5zNkVlbB4nUjud0ClCSWH5EIJRx5GHG1I31saeEiiiwVmMjKSRksdTEsWDQagdPUO9AyEsgQMTRDIjbwApvKjcCimPYe5C5rmum99EhFFKR0i9chsCIkbPoVSbB/8HHRVQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733545773; c=relaxed/simple; bh=0wDoUw6LbUneL0nxcXD1meOE876oW8D2ufKnETDTkHU=; h=Date:To:From:Subject:Message-Id; b=FYC/dFFcRc2+Wrxf+ImrxtJPzL5gvWKOMakkzJWBAmtZTDl9F7JlPj5Td+ryfNlwKz9iT6qiK+KvVi/gjkq0PtZdHamnw5sv/KRfOj2BEHxuSBHOMRX5XoJhyP4xrDYLf7wtg0tQk63UktUI8uLk1nuxMpoHYoi2iUMb4FeCVZE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=HxiNVNIs; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="HxiNVNIs" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C40AFC4CECD; Sat, 7 Dec 2024 04:29:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1733545772; bh=0wDoUw6LbUneL0nxcXD1meOE876oW8D2ufKnETDTkHU=; h=Date:To:From:Subject:From; b=HxiNVNIsoRt3LjtOU0DZTqr2kpU1Lf4WlB8Lh/+c9ZF1eDhXq7S6iGxaIHXbdFLdo rlTosrQX6q8iPpvhnhIjNJHyNsy5BB83T4kV6Ln31OQHmDh1KNa9Q5PVo+Ng9ONvUm 7ZWk9R8p7/WGfVvjzJ7RVkCIlh+GqmhqC808L4s8= Date: Fri, 06 Dec 2024 20:29:32 -0800 To: mm-commits@vger.kernel.org,willy@infradead.org,vbabka@suse.cz,souravpanda@google.com,shakeel.butt@linux.dev,richard.weiyang@gmail.com,peterz@infradead.org,peterx@redhat.com,paulmck@kernel.org,pasha.tatashin@soleen.com,oleg@redhat.com,mjguzik@gmail.com,minchan@google.com,mhocko@suse.com,mgorman@techsingularity.net,lorenzo.stoakes@oracle.com,Liam.Howlett@Oracle.com,jannh@google.com,hughd@google.com,hdanton@sina.com,hannes@cmpxchg.org,dhowells@redhat.com,david@redhat.com,dave@stgolabs.net,corbet@lwn.net,brauner@kernel.org,surenb@google.com,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-slab-allow-freeptr_offset-to-be-used-with-ctor.patch added to mm-unstable branch Message-Id: <20241207042932.C40AFC4CECD@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm/slab: allow freeptr_offset to be used with ctor has been added to the -mm mm-unstable branch. Its filename is mm-slab-allow-freeptr_offset-to-be-used-with-ctor.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-slab-allow-freeptr_offset-to-be-used-with-ctor.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Suren Baghdasaryan Subject: mm/slab: allow freeptr_offset to be used with ctor Date: Fri, 6 Dec 2024 14:52:02 -0800 There is no real reason to prevent freeptr_offset usage when a slab cache has a ctor. The only real limitation is that any field unioned with the free pointer and initialized by ctor will be overwritten since free pointer is set after @ctor invocation. Document this limitation and enable usage of freeptr_offset with ctor. Link: https://lkml.kernel.org/r/20241206225204.4008261-6-surenb@google.com Signed-off-by: Suren Baghdasaryan Suggested-by: Vlastimil Babka Cc: Christian Brauner Cc: David Hildenbrand Cc: David Howells Cc: Davidlohr Bueso Cc: Hillf Danton Cc: Hugh Dickins Cc: Jann Horn Cc: Johannes Weiner Cc: Jonathan Corbet Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Mateusz Guzik Cc: Matthew Wilcox Cc: Mel Gorman Cc: Michal Hocko Cc: Minchan Kim Cc: Oleg Nesterov Cc: Pasha Tatashin Cc: Paul E. McKenney Cc: Peter Xu Cc: Peter Zijlstra Cc: Shakeel Butt Cc: Sourav Panda Cc: Wei Yang Signed-off-by: Andrew Morton --- include/linux/slab.h | 5 +++-- mm/slub.c | 2 +- 2 files changed, 4 insertions(+), 3 deletions(-) --- a/include/linux/slab.h~mm-slab-allow-freeptr_offset-to-be-used-with-ctor +++ a/include/linux/slab.h @@ -305,8 +305,9 @@ struct kmem_cache_args { * Using %0 as a value for @freeptr_offset is valid. If @freeptr_offset * is specified, %use_freeptr_offset must be set %true. * - * Note that @ctor currently isn't supported with custom free pointers - * as a @ctor requires an external free pointer. + * Note that fields unioned with free pointer cannot be initialized by + * @ctor since free pointer is set after @ctor invocation, so those + * values will be overwritten. */ unsigned int freeptr_offset; /** --- a/mm/slub.c~mm-slab-allow-freeptr_offset-to-be-used-with-ctor +++ a/mm/slub.c @@ -5462,7 +5462,7 @@ static int calculate_sizes(struct kmem_c s->inuse = size; if (((flags & SLAB_TYPESAFE_BY_RCU) && !args->use_freeptr_offset) || - (flags & SLAB_POISON) || s->ctor || + (flags & SLAB_POISON) || (s->ctor && !args->use_freeptr_offset) || ((flags & SLAB_RED_ZONE) && (s->object_size < sizeof(void *) || slub_debug_orig_size(s)))) { /* _ Patches currently in -mm which might be from surenb@google.com are alloc_tag-fix-module-allocation-tags-populated-area-calculation.patch alloc_tag-fix-set_codetag_empty-when-config_mem_alloc_profiling_debug.patch seqlock-add-raw_seqcount_try_begin.patch mm-convert-mm_lock_seq-to-a-proper-seqcount.patch mm-introduce-mmap_lock_speculate_try_beginretry.patch mm-introduce-vma_start_read_locked_nested-helpers.patch mm-move-per-vma-lock-into-vm_area_struct.patch mm-mark-vma-as-detached-until-its-added-into-vma-tree.patch mm-make-vma-cache-slab_typesafe_by_rcu.patch mm-slab-allow-freeptr_offset-to-be-used-with-ctor.patch docs-mm-document-latest-changes-to-vm_lock.patch