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[220.245.19.62]) by smtp.gmail.com with ESMTPSA id 7sm3912834pgw.85.2020.07.09.18.57.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 09 Jul 2020 18:57:21 -0700 (PDT) From: Nicholas Piggin To: linux-arch@vger.kernel.org Cc: Nicholas Piggin , x86@kernel.org, Mathieu Desnoyers , Arnd Bergmann , Peter Zijlstra , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org, Anton Blanchard Subject: [RFC PATCH 3/7] mm: introduce exit_lazy_tlb Date: Fri, 10 Jul 2020 11:56:42 +1000 Message-Id: <20200710015646.2020871-4-npiggin@gmail.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20200710015646.2020871-1-npiggin@gmail.com> References: <20200710015646.2020871-1-npiggin@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Signed-off-by: Nicholas Piggin --- fs/exec.c | 5 +++-- include/asm-generic/mmu_context.h | 20 ++++++++++++++++++++ kernel/kthread.c | 1 + kernel/sched/core.c | 2 ++ 4 files changed, 26 insertions(+), 2 deletions(-) diff --git a/fs/exec.c b/fs/exec.c index e6e8a9a70327..e2ab71e88293 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1117,9 +1117,10 @@ static int exec_mmap(struct mm_struct *mm) setmax_mm_hiwater_rss(&tsk->signal->maxrss, old_mm); mm_update_next_owner(old_mm); mmput(old_mm); - return 0; + } else { + exit_lazy_tlb(active_mm, tsk); + mmdrop(active_mm); } - mmdrop(active_mm); return 0; } diff --git a/include/asm-generic/mmu_context.h b/include/asm-generic/mmu_context.h index 86cea80a50df..3fc4c3879b79 100644 --- a/include/asm-generic/mmu_context.h +++ b/include/asm-generic/mmu_context.h @@ -24,6 +24,26 @@ static inline void enter_lazy_tlb(struct mm_struct *mm, } #endif +/* + * exit_lazy_tlb - Called after switching away from a lazy TLB mode mm. + * + * mm: the lazy mm context that was switched away from + * tsk: the task that was switched to non-lazy mm + * + * tsk->mm will not be NULL. + * + * Note this is not symmetrical to enter_lazy_tlb, this is not + * called when tasks switch into the lazy mm, it's called after the + * lazy mm becomes non-lazy (either switched to a different mm or the + * owner of the mm returns). + */ +#ifndef exit_lazy_tlb +static inline void exit_lazy_tlb(struct mm_struct *mm, + struct task_struct *tsk) +{ +} +#endif + /** * init_new_context - Initialize context of a new mm_struct. * @tsk: task struct for the mm diff --git a/kernel/kthread.c b/kernel/kthread.c index 132f84a5fde3..e813d92f2eab 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -1253,6 +1253,7 @@ void kthread_use_mm(struct mm_struct *mm) if (active_mm != mm) mmdrop(active_mm); + exit_lazy_tlb(active_mm, tsk); to_kthread(tsk)->oldfs = get_fs(); set_fs(USER_DS); diff --git a/kernel/sched/core.c b/kernel/sched/core.c index ca5db40392d4..debc917bc69b 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3439,6 +3439,8 @@ context_switch(struct rq *rq, struct task_struct *prev, switch_mm_irqs_off(prev->active_mm, next->mm, next); if (!prev->mm) { // from kernel + exit_lazy_tlb(prev->active_mm, next); + /* will mmdrop() in finish_task_switch(). */ rq->prev_mm = prev->active_mm; prev->active_mm = NULL; -- 2.23.0