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AJvYcCVZpADaFykmmRhc0JutAXeS8FAda89xrnJ1QK1DhgK78UraEStdYzUUMqK4s8HJ/7LqYU0S9PoCfw==@kvack.org X-Gm-Message-State: AOJu0YyMluPLBRcfJps2Qv8X17QyhgTGGSw4ykNk5yGzRioxKULSGwAM 7pSh59TrR7in4G897yy906beW+VyV6Y4VA3ozcD9CD6GeuEctlmpWnY28YhVs9a2p5CnEoqF8MW GCQ== X-Google-Smtp-Source: AGHT+IGAr2xLbuXi2R908ZY5it7N2onoqChj/Zox7EvU+cfvoLneDmddmW0yL/ElwVm7zYdY6Kk+YCxDfGI= X-Received: from pjbpq10.prod.google.com ([2002:a17:90b:3d8a:b0:2ee:4b37:f869]) (user=surenb job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:3a43:b0:2ee:94a0:255c with SMTP id 98e67ed59e1d1-2f4536d25fcmr36257223a91.13.1735232865882; Thu, 26 Dec 2024 09:07:45 -0800 (PST) Date: Thu, 26 Dec 2024 09:07:08 -0800 In-Reply-To: <20241226170710.1159679-1-surenb@google.com> Mime-Version: 1.0 References: <20241226170710.1159679-1-surenb@google.com> X-Mailer: git-send-email 2.47.1.613.gc27f4b7a9f-goog Message-ID: <20241226170710.1159679-17-surenb@google.com> Subject: [PATCH v7 16/17] mm: make vma cache SLAB_TYPESAFE_BY_RCU From: Suren Baghdasaryan To: akpm@linux-foundation.org Cc: peterz@infradead.org, willy@infradead.org, liam.howlett@oracle.com, lorenzo.stoakes@oracle.com, mhocko@suse.com, vbabka@suse.cz, hannes@cmpxchg.org, mjguzik@gmail.com, oliver.sang@intel.com, mgorman@techsingularity.net, david@redhat.com, peterx@redhat.com, oleg@redhat.com, dave@stgolabs.net, paulmck@kernel.org, brauner@kernel.org, dhowells@redhat.com, hdanton@sina.com, hughd@google.com, lokeshgidra@google.com, minchan@google.com, jannh@google.com, shakeel.butt@linux.dev, souravpanda@google.com, pasha.tatashin@soleen.com, klarasmodin@gmail.com, corbet@lwn.net, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@android.com, surenb@google.com X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: B8BB910000C X-Stat-Signature: ptphpzguwfca3itb55y989ajkk8zjy1c X-Rspam-User: X-HE-Tag: 1735232786-522001 X-HE-Meta: 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 iPFzqDrK 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: To enable SLAB_TYPESAFE_BY_RCU for vma cache we need to ensure that object reuse before RCU grace period is over will be detected by lock_vma_under_rcu(). Current checks are sufficient as long as vma is detached before it is freed. Implement this guarantee by calling vma_ensure_detached() before vma is freed and make vm_area_cachep SLAB_TYPESAFE_BY_RCU. This will facilitate vm_area_struct reuse and will minimize the number of call_rcu() calls. Signed-off-by: Suren Baghdasaryan --- include/linux/mm.h | 2 -- include/linux/mm_types.h | 10 +++++++--- include/linux/slab.h | 6 ------ kernel/fork.c | 31 +++++++++---------------------- mm/mmap.c | 3 ++- mm/vma.c | 10 +++------- mm/vma.h | 2 +- tools/testing/vma/vma_internal.h | 7 +------ 8 files changed, 23 insertions(+), 48 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 56a7d70ca5bd..017d70e1d432 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -258,8 +258,6 @@ void setup_initial_init_mm(void *start_code, void *end_code, struct vm_area_struct *vm_area_alloc(struct mm_struct *); struct vm_area_struct *vm_area_dup(struct vm_area_struct *); void vm_area_free(struct vm_area_struct *); -/* Use only if VMA has no other users */ -void __vm_area_free(struct vm_area_struct *vma); #ifndef CONFIG_MMU extern struct rb_root nommu_region_tree; diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index b5312421dec6..3ca4695f6d0f 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -574,6 +574,12 @@ static inline void *folio_get_private(struct folio *folio) typedef unsigned long vm_flags_t; +/* + * freeptr_t represents a SLUB freelist pointer, which might be encoded + * and not dereferenceable if CONFIG_SLAB_FREELIST_HARDENED is enabled. + */ +typedef struct { unsigned long v; } freeptr_t; + /* * A region containing a mapping of a non-memory backed file under NOMMU * conditions. These are held in a global tree and are pinned by the VMAs that @@ -687,9 +693,7 @@ struct vm_area_struct { unsigned long vm_start; unsigned long vm_end; }; -#ifdef CONFIG_PER_VMA_LOCK - struct rcu_head vm_rcu; /* Used for deferred freeing. */ -#endif + freeptr_t vm_freeptr; /* Pointer used by SLAB_TYPESAFE_BY_RCU */ }; /* diff --git a/include/linux/slab.h b/include/linux/slab.h index 10a971c2bde3..681b685b6c4e 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -234,12 +234,6 @@ enum _slab_flag_bits { #define SLAB_NO_OBJ_EXT __SLAB_FLAG_UNUSED #endif -/* - * freeptr_t represents a SLUB freelist pointer, which might be encoded - * and not dereferenceable if CONFIG_SLAB_FREELIST_HARDENED is enabled. - */ -typedef struct { unsigned long v; } freeptr_t; - /* * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests. * diff --git a/kernel/fork.c b/kernel/fork.c index 7a0800d48112..da3b1ebfd282 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -471,7 +471,7 @@ struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig) return new; } -void __vm_area_free(struct vm_area_struct *vma) +void vm_area_free(struct vm_area_struct *vma) { /* The vma should be detached while being destroyed. */ vma_assert_detached(vma); @@ -480,25 +480,6 @@ void __vm_area_free(struct vm_area_struct *vma) kmem_cache_free(vm_area_cachep, vma); } -#ifdef CONFIG_PER_VMA_LOCK -static void vm_area_free_rcu_cb(struct rcu_head *head) -{ - struct vm_area_struct *vma = container_of(head, struct vm_area_struct, - vm_rcu); - - __vm_area_free(vma); -} -#endif - -void vm_area_free(struct vm_area_struct *vma) -{ -#ifdef CONFIG_PER_VMA_LOCK - call_rcu(&vma->vm_rcu, vm_area_free_rcu_cb); -#else - __vm_area_free(vma); -#endif -} - static void account_kernel_stack(struct task_struct *tsk, int account) { if (IS_ENABLED(CONFIG_VMAP_STACK)) { @@ -3144,6 +3125,11 @@ void __init mm_cache_init(void) void __init proc_caches_init(void) { + struct kmem_cache_args args = { + .use_freeptr_offset = true, + .freeptr_offset = offsetof(struct vm_area_struct, vm_freeptr), + }; + sighand_cachep = kmem_cache_create("sighand_cache", sizeof(struct sighand_struct), 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_TYPESAFE_BY_RCU| @@ -3160,8 +3146,9 @@ void __init proc_caches_init(void) sizeof(struct fs_struct), 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, NULL); - vm_area_cachep = KMEM_CACHE(vm_area_struct, - SLAB_HWCACHE_ALIGN|SLAB_NO_MERGE|SLAB_PANIC| + vm_area_cachep = kmem_cache_create("vm_area_struct", + sizeof(struct vm_area_struct), &args, + SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_TYPESAFE_BY_RCU| SLAB_ACCOUNT); mmap_init(); nsproxy_cache_init(); diff --git a/mm/mmap.c b/mm/mmap.c index 3cc8de07411d..7fdc4207fe98 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1364,7 +1364,8 @@ void exit_mmap(struct mm_struct *mm) do { if (vma->vm_flags & VM_ACCOUNT) nr_accounted += vma_pages(vma); - remove_vma(vma, /* unreachable = */ true); + vma_mark_detached(vma); + remove_vma(vma); count++; cond_resched(); vma = vma_next(&vmi); diff --git a/mm/vma.c b/mm/vma.c index 4a3deb6f9662..e37eb384d118 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -406,18 +406,14 @@ static bool can_vma_merge_right(struct vma_merge_struct *vmg, /* * Close a vm structure and free it. */ -void remove_vma(struct vm_area_struct *vma, bool unreachable) +void remove_vma(struct vm_area_struct *vma) { might_sleep(); vma_close(vma); if (vma->vm_file) fput(vma->vm_file); mpol_put(vma_policy(vma)); - if (unreachable) { - vma_mark_detached(vma); - __vm_area_free(vma); - } else - vm_area_free(vma); + vm_area_free(vma); } /* @@ -1199,7 +1195,7 @@ static void vms_complete_munmap_vmas(struct vma_munmap_struct *vms, /* Remove and clean up vmas */ mas_set(mas_detach, 0); mas_for_each(mas_detach, vma, ULONG_MAX) - remove_vma(vma, /* unreachable = */ false); + remove_vma(vma); vm_unacct_memory(vms->nr_accounted); validate_mm(mm); diff --git a/mm/vma.h b/mm/vma.h index 18c9e49b1eae..d6803626151d 100644 --- a/mm/vma.h +++ b/mm/vma.h @@ -173,7 +173,7 @@ int do_vmi_munmap(struct vma_iterator *vmi, struct mm_struct *mm, unsigned long start, size_t len, struct list_head *uf, bool unlock); -void remove_vma(struct vm_area_struct *vma, bool unreachable); +void remove_vma(struct vm_area_struct *vma); void unmap_region(struct ma_state *mas, struct vm_area_struct *vma, struct vm_area_struct *prev, struct vm_area_struct *next); diff --git a/tools/testing/vma/vma_internal.h b/tools/testing/vma/vma_internal.h index 1e8cd2f013fa..c7c580ec9a2d 100644 --- a/tools/testing/vma/vma_internal.h +++ b/tools/testing/vma/vma_internal.h @@ -693,14 +693,9 @@ static inline void mpol_put(struct mempolicy *) { } -static inline void __vm_area_free(struct vm_area_struct *vma) -{ - free(vma); -} - static inline void vm_area_free(struct vm_area_struct *vma) { - __vm_area_free(vma); + free(vma); } static inline void lru_add_drain(void)