From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3C20AC4363A for ; Mon, 26 Oct 2020 17:34:12 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A19D221D42 for ; Mon, 26 Oct 2020 17:34:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A19D221D42 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 937226B0062; Mon, 26 Oct 2020 13:34:09 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 60E086B005C; Mon, 26 Oct 2020 13:34:09 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 488316B006C; Mon, 26 Oct 2020 13:34:09 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0169.hostedemail.com [216.40.44.169]) by kanga.kvack.org (Postfix) with ESMTP id 149D86B0062 for ; Mon, 26 Oct 2020 13:34:09 -0400 (EDT) Received: from smtpin02.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id A7D00180AD804 for ; Mon, 26 Oct 2020 17:34:08 +0000 (UTC) X-FDA: 77414774976.02.hate75_0200d7327275 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin02.hostedemail.com (Postfix) with ESMTP id 8789510097AA2 for ; Mon, 26 Oct 2020 17:34:08 +0000 (UTC) X-HE-Tag: hate75_0200d7327275 X-Filterd-Recvd-Size: 6813 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf26.hostedemail.com (Postfix) with ESMTP for ; Mon, 26 Oct 2020 17:34:08 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id A7F63AE3B; Mon, 26 Oct 2020 17:34:06 +0000 (UTC) From: Vlastimil Babka To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Alexander Potapenko , Kees Cook , Michal Hocko , David Hildenbrand , Mateusz Nosek , Vlastimil Babka Subject: [PATCH 2/3] mm, page_poison: use static key more efficiently Date: Mon, 26 Oct 2020 18:33:57 +0100 Message-Id: <20201026173358.14704-3-vbabka@suse.cz> X-Mailer: git-send-email 2.29.0 In-Reply-To: <20201026173358.14704-1-vbabka@suse.cz> References: <20201026173358.14704-1-vbabka@suse.cz> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable 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: Commit 11c9c7edae06 ("mm/page_poison.c: replace bool variable with static= key") changed page_poisoning_enabled() to a static key check. However, the func= tion is not inlined, so each check still involves a function call with overhea= d not eliminated when page poisoning is disabled. Analogically to how debug_pagealloc is handled, this patch converts page_poisoning_enabled() back to boolean check, and introduces page_poisoning_enabled_static() for fast paths. Both functions are inline= d. Also optimize the check that enables page poisoning instead of debug_page= alloc for architectures without proper debug_pagealloc support. Move the check = to init_mem_debugging() to enable a single static key instead of having two static branches in page_poisoning_enabled_static(). Signed-off-by: Vlastimil Babka --- drivers/virtio/virtio_balloon.c | 2 +- include/linux/mm.h | 16 ++++++++++++- mm/page_alloc.c | 13 ++++++++++- mm/page_poison.c | 40 +++++---------------------------- 4 files changed, 34 insertions(+), 37 deletions(-) diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_ball= oon.c index 481611c09dae..e53faed6ba93 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -1116,7 +1116,7 @@ static int virtballoon_validate(struct virtio_devic= e *vdev) */ if (!want_init_on_free() && (IS_ENABLED(CONFIG_PAGE_POISONING_NO_SANITY) || - !page_poisoning_enabled())) + !page_poisoning_enabled_static())) __virtio_clear_bit(vdev, VIRTIO_BALLOON_F_PAGE_POISON); else if (!virtio_has_feature(vdev, VIRTIO_BALLOON_F_PAGE_POISON)) __virtio_clear_bit(vdev, VIRTIO_BALLOON_F_REPORTING); diff --git a/include/linux/mm.h b/include/linux/mm.h index c6a0adccf2fe..c1d0ed2b8724 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2867,10 +2867,24 @@ extern int apply_to_existing_page_range(struct mm= _struct *mm, =20 extern void init_mem_debugging(void); #ifdef CONFIG_PAGE_POISONING -extern bool page_poisoning_enabled(void); extern void kernel_poison_pages(struct page *page, int numpages, int ena= ble); +extern bool _page_poisoning_enabled_early; +DECLARE_STATIC_KEY_FALSE(_page_poisoning_enabled); +static inline bool page_poisoning_enabled(void) +{ + return _page_poisoning_enabled_early; +} +/* + * For use in fast paths after init_mem_debugging() has run, or when a + * false negative result is not harmful when called too early. + */ +static inline bool page_poisoning_enabled_static(void) +{ + return (static_branch_unlikely(&_page_poisoning_enabled)); +} #else static inline bool page_poisoning_enabled(void) { return false; } +static inline bool page_poisoning_enabled_static(void) { return false; } static inline void kernel_poison_pages(struct page *page, int numpages, int enable) { } #endif diff --git a/mm/page_alloc.c b/mm/page_alloc.c index b168c58ef337..2a1be197649d 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -777,6 +777,17 @@ void init_mem_debugging() } } =20 +#ifdef CONFIG_PAGE_POISONING + /* + * Page poisoning is debug page alloc for some arches. If + * either of those options are enabled, enable poisoning. + */ + if (page_poisoning_enabled() || + (!IS_ENABLED(CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC) && + debug_pagealloc_enabled())) + static_branch_enable(&_page_poisoning_enabled); +#endif + #ifdef CONFIG_DEBUG_PAGEALLOC if (!debug_pagealloc_enabled()) return; @@ -2208,7 +2219,7 @@ static inline int check_new_page(struct page *page) static inline bool free_pages_prezeroed(void) { return (IS_ENABLED(CONFIG_PAGE_POISONING_ZERO) && - page_poisoning_enabled()) || want_init_on_free(); + page_poisoning_enabled_static()) || want_init_on_free(); } =20 #ifdef CONFIG_DEBUG_VM diff --git a/mm/page_poison.c b/mm/page_poison.c index ae0482cded87..d1f06b70a779 100644 --- a/mm/page_poison.c +++ b/mm/page_poison.c @@ -8,45 +8,17 @@ #include #include =20 -static DEFINE_STATIC_KEY_FALSE_RO(want_page_poisoning); +bool _page_poisoning_enabled_early; +EXPORT_SYMBOL(_page_poisoning_enabled_early); +DEFINE_STATIC_KEY_FALSE_RO(_page_poisoning_enabled); +EXPORT_SYMBOL(_page_poisoning_enabled); =20 static int __init early_page_poison_param(char *buf) { - int ret; - bool tmp; - - ret =3D strtobool(buf, &tmp); - if (ret) - return ret; - - if (tmp) - static_branch_enable(&want_page_poisoning); - else - static_branch_disable(&want_page_poisoning); - - return 0; + return kstrtobool(buf, &_page_poisoning_enabled_early); } early_param("page_poison", early_page_poison_param); =20 -/** - * page_poisoning_enabled - check if page poisoning is enabled - * - * Return true if page poisoning is enabled, or false if not. - */ -bool page_poisoning_enabled(void) -{ - /* - * Assumes that debug_pagealloc_enabled is set before - * memblock_free_all. - * Page poisoning is debug page alloc for some arches. If - * either of those options are enabled, enable poisoning. - */ - return (static_branch_unlikely(&want_page_poisoning) || - (!IS_ENABLED(CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC) && - debug_pagealloc_enabled())); -} -EXPORT_SYMBOL_GPL(page_poisoning_enabled); - static void poison_page(struct page *page) { void *addr =3D kmap_atomic(page); @@ -127,7 +99,7 @@ static void unpoison_pages(struct page *page, int n) =20 void kernel_poison_pages(struct page *page, int numpages, int enable) { - if (!page_poisoning_enabled()) + if (!page_poisoning_enabled_static()) return; =20 if (enable) --=20 2.29.0