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Sat, 10 Dec 2022 18:01:04 -0500 X-MC-Unique: EeB-s45IOpmbUgijCnkwMQ-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 4D357806002; Sat, 10 Dec 2022 23:01:04 +0000 (UTC) Received: from llong.com (unknown [10.22.8.68]) by smtp.corp.redhat.com (Postfix) with ESMTP id 097EE40C6EC2; Sat, 10 Dec 2022 23:01:04 +0000 (UTC) From: Waiman Long To: Catalin Marinas , Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Muchun Song , Waiman Long Subject: [PATCH 1/2] mm/kmemleak: Simplify kmemleak_cond_resched() usage Date: Sat, 10 Dec 2022 18:00:47 -0500 Message-Id: <20221210230048.2841047-2-longman@redhat.com> In-Reply-To: <20221210230048.2841047-1-longman@redhat.com> References: <20221210230048.2841047-1-longman@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 196E940011 X-Rspam-User: X-Stat-Signature: thcocbehre5qqeomxmpd6n6knqp3779g X-HE-Tag: 1670713269-15683 X-HE-Meta: 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 ftQ== 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: The presence of a pinned argument and the 64k loop count make kmemleak_cond_resched() a bit more complex to read. The pinned argument is used only by first kmemleak_scan() loop. Simplify the usage of kmemleak_cond_resched() by removing the pinned argument and always do a get_object()/put_object() sequence. In addition, the 64k loop is removed by using need_resched() to decide if kmemleak_cond_resched() should be called. Signed-off-by: Waiman Long --- mm/kmemleak.c | 48 ++++++++++++------------------------------------ 1 file changed, 12 insertions(+), 36 deletions(-) diff --git a/mm/kmemleak.c b/mm/kmemleak.c index 646e2979641f..8c44f70ed457 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -1463,22 +1463,17 @@ static void scan_gray_list(void) /* * Conditionally call resched() in a object iteration loop while making sure * that the given object won't go away without RCU read lock by performing a - * get_object() if !pinned. - * - * Return: false if can't do a cond_resched() due to get_object() failure - * true otherwise + * get_object() if necessaary. */ -static bool kmemleak_cond_resched(struct kmemleak_object *object, bool pinned) +static void kmemleak_cond_resched(struct kmemleak_object *object) { - if (!pinned && !get_object(object)) - return false; + if (!get_object(object)) + return; /* Try next object */ rcu_read_unlock(); cond_resched(); rcu_read_lock(); - if (!pinned) - put_object(object); - return true; + put_object(object); } /* @@ -1492,15 +1487,12 @@ static void kmemleak_scan(void) struct zone *zone; int __maybe_unused i; int new_leaks = 0; - int loop_cnt = 0; jiffies_last_scan = jiffies; /* prepare the kmemleak_object's */ rcu_read_lock(); list_for_each_entry_rcu(object, &object_list, object_list) { - bool obj_pinned = false; - raw_spin_lock_irq(&object->lock); #ifdef DEBUG /* @@ -1526,19 +1518,13 @@ static void kmemleak_scan(void) /* reset the reference count (whiten the object) */ object->count = 0; - if (color_gray(object) && get_object(object)) { + if (color_gray(object) && get_object(object)) list_add_tail(&object->gray_list, &gray_list); - obj_pinned = true; - } raw_spin_unlock_irq(&object->lock); - /* - * Do a cond_resched() every 64k objects to avoid soft lockup. - */ - if (!(++loop_cnt & 0xffff) && - !kmemleak_cond_resched(object, obj_pinned)) - loop_cnt--; /* Try again on next object */ + if (need_resched()) + kmemleak_cond_resched(object); } rcu_read_unlock(); @@ -1605,14 +1591,9 @@ static void kmemleak_scan(void) * scan and color them gray until the next scan. */ rcu_read_lock(); - loop_cnt = 0; list_for_each_entry_rcu(object, &object_list, object_list) { - /* - * Do a cond_resched() every 64k objects to avoid soft lockup. - */ - if (!(++loop_cnt & 0xffff) && - !kmemleak_cond_resched(object, false)) - loop_cnt--; /* Try again on next object */ + if (need_resched()) + kmemleak_cond_resched(object); /* * This is racy but we can save the overhead of lock/unlock @@ -1647,14 +1628,9 @@ static void kmemleak_scan(void) * Scanning result reporting. */ rcu_read_lock(); - loop_cnt = 0; list_for_each_entry_rcu(object, &object_list, object_list) { - /* - * Do a cond_resched() every 64k objects to avoid soft lockup. - */ - if (!(++loop_cnt & 0xffff) && - !kmemleak_cond_resched(object, false)) - loop_cnt--; /* Try again on next object */ + if (need_resched()) + kmemleak_cond_resched(object); /* * This is racy but we can save the overhead of lock/unlock -- 2.31.1