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bh=29YuznebDbhH7LJ7uqA8Selv98qAa02JmRVPnHaqVO4=; b=A91smaaO37XfvJoDn2eJgGgS0XTGwMFAR6+jf0mRbZ5QOAcdI4jzvP29vIuz3uO+bI jdj4WhMmKkJSwei3zvI6+oYW+U+TKUFAbdud7vtGv2gg1FtYW9JruRmwr7BGKpK/zUnM s1hLGY10lU87IC/KeeOQkjj27glT0NMVai0fk/6q65NPnG9DgW4mfBujFdOy54yH3H08 qK40dVwWF+K6/WAQbzgYMyabMvKa2ISvCM++6AFbjmydjWS6/3oGzkg37mAcdEi2r21T LAaIDCGQCFGprizkfggYZJiMv3XuZ0ObYWCeL9Ik+ySdCA547KIC3nKF0bZH1mIhECJ6 B7JA== X-Gm-Message-State: AO0yUKUXN1drzzkDelNFTLBIyc/K0czofswHBkunfD3nwwNjKyuZyUCQ iNkRgs0JbYzEj12MqAR1UcgkfLSg9aU= X-Received: from surenb-desktop.mtv.corp.google.com ([2620:15c:211:200:e1f6:21d1:eead:3897]) (user=surenb job=sendgmr) by 2002:a25:9390:0:b0:a53:5825:f25b with SMTP id a16-20020a259390000000b00a535825f25bmr6018468ybm.0.1677519421007; Mon, 27 Feb 2023 09:37:01 -0800 (PST) Date: Mon, 27 Feb 2023 09:36:09 -0800 In-Reply-To: <20230227173632.3292573-1-surenb@google.com> Mime-Version: 1.0 References: <20230227173632.3292573-1-surenb@google.com> X-Mailer: git-send-email 2.39.2.722.g9855ee24e9-goog Message-ID: <20230227173632.3292573-11-surenb@google.com> Subject: [PATCH v4 10/33] 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, paulmck@kernel.org, mingo@redhat.com, will@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, chriscli@google.com, axelrasmussen@google.com, joelaf@google.com, minchan@google.com, rppt@kernel.org, jannh@google.com, shakeelb@google.com, tatashin@google.com, edumazet@google.com, gthelen@google.com, gurua@google.com, arjunroy@google.com, soheil@google.com, leewalsh@google.com, posk@google.com, michalechner92@googlemail.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, Suren Baghdasaryan 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?1759006718539615720?= X-GMAIL-MSGID: =?utf-8?q?1759006718539615720?= 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 | 20 +++++++++++++++++++- 2 files changed, 29 insertions(+), 4 deletions(-) diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 22b2ac82bffd..64a6b3f6b74f 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -480,9 +480,16 @@ 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 abfcf95734c7..a63b739aeca9 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -479,12 +479,30 @@ struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig) return new; } -void vm_area_free(struct vm_area_struct *vma) +static void __vm_area_free(struct vm_area_struct *vma) { free_anon_vma_name(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)) {