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b=JDGT057YotqaJUSdir5KmN+Jl5ptw2nNXgLoxRjoGKKMDlQ9glv9FolEVJS50/ldy rESgVlL3FtpMk2/8euhOLgExEvxrwX2ZgfYX5w5nkMlkoMBqWcJGIXw8UuXWnM9m+z lEGE2JVClQdV4QwnlXSZPyTAgorq9fhTsh1h3yDSFElmKEuAGqiLtKdXPaetwinquY BAJ6JWi2lxvZEzopFmdi4g6BKfwLS3AuTrtKrfqaPYXp6ivxGadt4ANl9K5V8oxM1W aLi0kVocb1hst4K9iGWp6ZfIWUvBLDH/m2eaB/hDtrab2HQ6QGOGWhHomO09LoQkea uTtz6wpYW9Tzw== From: "Vlastimil Babka (SUSE)" Date: Wed, 10 Jun 2026 17:40:16 +0200 Subject: [PATCH v2 14/16] mm/slab: introduce kmalloc_flags() MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260610-slab_alloc_flags-v2-14-7190909db118@kernel.org> References: <20260610-slab_alloc_flags-v2-0-7190909db118@kernel.org> In-Reply-To: <20260610-slab_alloc_flags-v2-0-7190909db118@kernel.org> To: Harry Yoo Cc: Hao Li , Christoph Lameter , David Rientjes , Roman Gushchin , Suren Baghdasaryan , Alexei Starovoitov , Andrew Morton , Johannes Weiner , Michal Hocko , Shakeel Butt , Alexander Potapenko , Marco Elver , Dmitry Vyukov , kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, "Vlastimil Babka (SUSE)" X-Mailer: b4 0.15.2 X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 0C801140005 X-Stat-Signature: s96taiahuncifi6osyosz6mo78tjdhw9 X-Rspam-User: X-HE-Tag: 1781106123-192611 X-HE-Meta: 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 8wWGdvFM PyXu9tP0qhmSK42cxjBlXleY7D6Kl9v69IiZD6J5clO3CEtAUcB9hKMTxAi8YHUDxkd2ggljwj5W6NacBxnY2ZRm3afTaUvn5yVmGdv8i3P2YPR6RAKloBtU8fFk2Gg8lxv0fUlpCsummoS/nhsz/9JwuSmtKDPp1aS8ParTesN8LcqmYVJ6bPnNgqgTmQ12mzGFOsN3ZyQKyUJ2WXkVGGMbC98BdHEDZh9sGAd3X0/+twEtaXoKknbzzs3TCih/8/jHAG+dxisxx2E+C+HZx5jwRdzC7rY064mcddRr8a4aUFWQ= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: With alloc_flags usage in slab, we can replace __GFP_NO_OBJ_EXT with an alloc flag that prevents kmalloc recursion. For that we need a version of kmalloc() that takes alloc_flags and use it in places that perform these potentially recursive kmalloc allocations (of sheaves or obj_ext arrays). Add this function, named kmalloc_flags(). Right now it's only useful for these nested allocations, so it doesn't need to optimize build-time constant sizes like kmalloc() or kmalloc_buckets. Since we need it to support both normal and non-spinning kmalloc_nolock() context through the SLAB_ALLOC_TRYLOCK flag, split out most of the special _kmalloc_nolock_noprof() implementation to __kmalloc_nolock_noprof() that takes a slab_alloc_context, and make _kmalloc_nolock_noprof() a simple tail calling wrapper with the proper context. kmalloc_flags() can thus determine whether to call __kmalloc_nolock_noprof() or __do_kmalloc_node(), based on the given alloc_flags. Signed-off-by: Vlastimil Babka (SUSE) --- mm/slab.h | 13 +++++++++++++ mm/slub.c | 56 +++++++++++++++++++++++++++++++++++++++++++------------- 2 files changed, 56 insertions(+), 13 deletions(-) diff --git a/mm/slab.h b/mm/slab.h index 4db6d8aa0ee3..45bfcfb35a9c 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -11,6 +11,7 @@ #include #include #include +#include /* * Internal slab definitions @@ -26,6 +27,18 @@ static inline bool alloc_flags_allow_spinning(const unsigned int alloc_flags) return !(alloc_flags & SLAB_ALLOC_TRYLOCK); } +void *__kmalloc_flags_noprof(DECL_TOKEN_PARAMS(size, token), gfp_t flags, + unsigned int alloc_flags, int node) + __assume_kmalloc_alignment __alloc_size(1); + +static __always_inline __alloc_size(1) void *_kmalloc_flags_noprof(size_t size, + gfp_t flags, unsigned int alloc_flags, int node, kmalloc_token_t token) +{ + return __kmalloc_flags_noprof(PASS_TOKEN_PARAMS(size, token), flags, alloc_flags, node); +} +#define kmalloc_flags_noprof(...) _kmalloc_flags_noprof(__VA_ARGS__, __kmalloc_token(__VA_ARGS__)) +#define kmalloc_flags(...) alloc_hooks(kmalloc_flags_noprof(__VA_ARGS__)) + #ifdef CONFIG_64BIT # ifdef system_has_cmpxchg128 # define system_has_freelist_aba() system_has_cmpxchg128() diff --git a/mm/slub.c b/mm/slub.c index 847cad5203b2..cbb38bd01e46 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -5386,14 +5386,14 @@ void *__kmalloc_noprof(DECL_TOKEN_PARAMS(size, token), gfp_t flags) } EXPORT_SYMBOL(__kmalloc_noprof); -void *_kmalloc_nolock_noprof(DECL_TOKEN_PARAMS(size, token), gfp_t gfp_flags, int node) +static void *__kmalloc_nolock_noprof(DECL_TOKEN_PARAMS(size, token), gfp_t gfp_flags, + int node, struct slab_alloc_context *ac) { - size_t orig_size = size; - unsigned int alloc_flags = SLAB_ALLOC_TRYLOCK; struct kmem_cache *s; bool can_retry = true; void *ret; + VM_WARN_ON_ONCE(alloc_flags_allow_spinning(ac->alloc_flags)); VM_WARN_ON_ONCE(gfp_flags & ~(__GFP_ACCOUNT | __GFP_ZERO | __GFP_NO_OBJ_EXT | __GFP_NOWARN | __GFP_NOMEMALLOC)); @@ -5430,23 +5430,17 @@ void *_kmalloc_nolock_noprof(DECL_TOKEN_PARAMS(size, token), gfp_t gfp_flags, in */ return NULL; - ret = alloc_from_pcs(s, gfp_flags, alloc_flags, node); + ret = alloc_from_pcs(s, gfp_flags, ac->alloc_flags, node); if (ret) goto success; - struct slab_alloc_context ac = { - .caller_addr = _RET_IP_, - .orig_size = orig_size, - .alloc_flags = alloc_flags, - }; - /* * Do not call slab_alloc_node(), since trylock mode isn't * compatible with slab_pre_alloc_hook/should_failslab and * kfence_alloc. Hence call __slab_alloc_node() (at most twice) * and slab_post_alloc_hook() directly. */ - ret = __slab_alloc_node(s, gfp_flags, node, &ac); + ret = __slab_alloc_node(s, gfp_flags, node, ac); /* * It's possible we failed due to trylock as we preempted someone with @@ -5469,11 +5463,23 @@ void *_kmalloc_nolock_noprof(DECL_TOKEN_PARAMS(size, token), gfp_t gfp_flags, in success: maybe_wipe_obj_freeptr(s, ret); - slab_post_alloc_hook(s, gfp_flags, 1, &ret, &ac); + slab_post_alloc_hook(s, gfp_flags, 1, &ret, ac); - ret = kasan_kmalloc(s, ret, orig_size, gfp_flags); + ret = kasan_kmalloc(s, ret, ac->orig_size, gfp_flags); return ret; } + +void *_kmalloc_nolock_noprof(DECL_TOKEN_PARAMS(size, token), gfp_t gfp_flags, int node) +{ + struct slab_alloc_context ac = { + .caller_addr = _RET_IP_, + .orig_size = size, + .alloc_flags = SLAB_ALLOC_TRYLOCK, + }; + + return __kmalloc_nolock_noprof(PASS_TOKEN_PARAMS(size, token), + gfp_flags, node, &ac); +} EXPORT_SYMBOL_GPL(_kmalloc_nolock_noprof); void *__kmalloc_node_track_caller_noprof(DECL_KMALLOC_PARAMS(size, b, token), gfp_t flags, @@ -5527,6 +5533,30 @@ void *__kmalloc_cache_node_noprof(struct kmem_cache *s, gfp_t gfpflags, } EXPORT_SYMBOL(__kmalloc_cache_node_noprof); +/* + * The only version of kmalloc_node() that takes alloc_flags and thus can + * determine on its own whether to handle the allocation via kmalloc_nolock() or + * normally + */ +void *__kmalloc_flags_noprof(DECL_TOKEN_PARAMS(size, token), gfp_t flags, + unsigned int alloc_flags, int node) +{ + struct slab_alloc_context ac = { + .caller_addr = _RET_IP_, + .orig_size = size, + .alloc_flags = alloc_flags, + }; + + if (alloc_flags_allow_spinning(alloc_flags)) { + return __do_kmalloc_node(size, NULL, flags, node, + PASS_TOKEN_PARAM(token), &ac); + } else { + return __kmalloc_nolock_noprof(PASS_TOKEN_PARAMS(size, token), + flags, node, &ac); + } +} + + static noinline void free_to_partial_list( struct kmem_cache *s, struct slab *slab, void *head, void *tail, int bulk_cnt, -- 2.54.0