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bh=D1pZqRdf8jzuIQZRLrMCJmLqIEvbyFYNYfXzudRZz6Y=; b=NV+uWW8kSqjnzXC7qxYInTBwa5wfHfVMsbOIQqaJNekLb+x92UzFDOITuhZVR35I6M maTYcagBmSw0p6cnWX89HQoEBJvKXb9HC4Goe4mRSE0CFeDkkIureH+3F/kWsmUTykEu QAbPgrH77pV5CpM3UqJ3AkCYpu6Ncz2J4oGtouexcSyikyhKH6ByLtagDS9ErMbkOE6r ViT1xBKbZQiSTFzm/T9E7orv1aCzM0CokbzxMzmOEmKxy3hiupTsRLk0rumgEZdQ5Pqe jGyF6CL5IDaHnnYhQOsIgljGyx+qK5WAP1pRaPUNMFamMOHOJWSFZneA5woLsMQ9EORT td+Q== X-Gm-Message-State: AFqh2kppwJH6haqOwDXv8UaB65ED3bl/GpTGkLwz6VFs7LRqjzVnYVa1 IwmsGmNXlqfR8JqNfMj6XbWlDVi0uuY= X-Received: from surenb-desktop.mtv.corp.google.com ([2620:15c:211:200:9393:6f7a:d410:55ca]) (user=surenb job=sendgmr) by 2002:a05:6870:649e:b0:143:509f:17f0 with SMTP id cz30-20020a056870649e00b00143509f17f0mr4940900oab.211.1673297643629; Mon, 09 Jan 2023 12:54:03 -0800 (PST) Date: Mon, 9 Jan 2023 12:53:04 -0800 In-Reply-To: <20230109205336.3665937-1-surenb@google.com> Mime-Version: 1.0 References: <20230109205336.3665937-1-surenb@google.com> X-Mailer: git-send-email 2.39.0.314.g84b9a713c41-goog Message-ID: <20230109205336.3665937-10-surenb@google.com> Subject: [PATCH 09/41] mm: rcu safe VMA freeing From: Suren Baghdasaryan To: akpm@linux-foundation.org Cc: michel@lespinasse.org, jglisse@google.com, mhocko@suse.com, vbabka@suse.cz, hannes@cmpxchg.org, mgorman@techsingularity.net, dave@stgolabs.net, willy@infradead.org, liam.howlett@oracle.com, peterz@infradead.org, ldufour@linux.ibm.com, laurent.dufour@fr.ibm.com, paulmck@kernel.org, luto@kernel.org, songliubraving@fb.com, peterx@redhat.com, david@redhat.com, dhowells@redhat.com, hughd@google.com, bigeasy@linutronix.de, kent.overstreet@linux.dev, punit.agrawal@bytedance.com, lstoakes@gmail.com, peterjung1337@gmail.com, rientjes@google.com, axelrasmussen@google.com, joelaf@google.com, minchan@google.com, jannh@google.com, shakeelb@google.com, tatashin@google.com, edumazet@google.com, gthelen@google.com, gurua@google.com, arjunroy@google.com, soheil@google.com, hughlynch@google.com, leewalsh@google.com, posk@google.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, x86@kernel.org, linux-kernel@vger.kernel.org, kernel-team@android.com, surenb@google.com X-Spam-Status: No, score=-9.6 required=5.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1754579872842800970?= X-GMAIL-MSGID: =?utf-8?q?1754579872842800970?= From: Michel Lespinasse This prepares for page faults handling under VMA lock, looking up VMAs under protection of an rcu read lock, instead of the usual mmap read lock. Signed-off-by: Michel Lespinasse Signed-off-by: Suren Baghdasaryan --- include/linux/mm_types.h | 13 ++++++++++--- kernel/fork.c | 13 +++++++++++++ 2 files changed, 23 insertions(+), 3 deletions(-) diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 4b6bce73fbb4..d5cdec1314fe 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -535,9 +535,16 @@ struct anon_vma_name { struct vm_area_struct { /* The first cache line has the info for VMA tree walking. */ - unsigned long vm_start; /* Our start address within vm_mm. */ - unsigned long vm_end; /* The first byte after our end address - within vm_mm. */ + union { + struct { + /* VMA covers [vm_start; vm_end) addresses within mm */ + unsigned long vm_start; + unsigned long vm_end; + }; +#ifdef CONFIG_PER_VMA_LOCK + struct rcu_head vm_rcu; /* Used for deferred freeing. */ +#endif + }; struct mm_struct *vm_mm; /* The address space we belong to. */ diff --git a/kernel/fork.c b/kernel/fork.c index 58aab6c889a4..5986817f393c 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -479,10 +479,23 @@ struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig) return new; } +#ifdef CONFIG_PER_VMA_LOCK +static void __vm_area_free(struct rcu_head *head) +{ + struct vm_area_struct *vma = container_of(head, struct vm_area_struct, + vm_rcu); + kmem_cache_free(vm_area_cachep, vma); +} +#endif + void vm_area_free(struct vm_area_struct *vma) { free_anon_vma_name(vma); +#ifdef CONFIG_PER_VMA_LOCK + call_rcu(&vma->vm_rcu, __vm_area_free); +#else kmem_cache_free(vm_area_cachep, vma); +#endif } static void account_kernel_stack(struct task_struct *tsk, int account)