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[192.237.175.120]) by mx.google.com with ESMTPS id n128si2553915itn.9.2016.07.20.09.14.10 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 20 Jul 2016 09:14:11 -0700 (PDT) Received-SPF: neutral (google.com: 192.237.175.120 is neither permitted nor denied by best guess record for domain of xen-devel-bounces@lists.xen.org) client-ip=192.237.175.120; Authentication-Results: mx.google.com; spf=neutral (google.com: 192.237.175.120 is neither permitted nor denied by best guess record for domain of xen-devel-bounces@lists.xen.org) smtp.mailfrom=xen-devel-bounces@lists.xen.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1bPu63-0007jb-UU; Wed, 20 Jul 2016 16:11:43 +0000 Received: from mail6.bemta5.messagelabs.com ([195.245.231.135]) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1bPu63-0007hh-9n for xen-devel@lists.xen.org; Wed, 20 Jul 2016 16:11:43 +0000 Received: from [85.158.139.211] by server-7.bemta-5.messagelabs.com id 01/C2-05127-EB2AF875; Wed, 20 Jul 2016 16:11:42 +0000 X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFrrGLMWRWlGSWpSXmKPExsVysyfVTXffov5 wg327WC2WfFzM4sDocXT3b6YAxijWzLyk/IoE1oz+1ceYCjqFK/rudzI2MF7l72Lk5BAS2MQo sWJbeRcjF5B9mlFi7+rTbCAJNgFNiTufPzGB2CIC0hLXPl9mBCliFmhnlFi+8R8LSEJYIEBi9 b8zYDaLgKrEna3n2EFsXgFXiXuLZ4HFJQTkJE4em8wKYnMCxc+f/MkIsdlFYtPbb8wTGLkXMD KsYlQvTi0qSy3SNdNLKspMzyjJTczM0TU0MNXLTS0uTkxPzUlMKtZLzs/dxAj0LwMQ7GCc2uB 8iFGSg0lJlFdVtDdciC8pP6UyI7E4I76oNCe1+BCjDAeHkgTv4oX94UKCRanpqRVpmTnAQINJ S3DwKInwHgdJ8xYXJOYWZ6ZDpE4xKkqJ824DSQiAJDJK8+DaYMF9iVFWSpiXEegQIZ6C1KLcz BJU+VeM4hyMSsK8h0Gm8GTmlcBNfwW0mAlo8RwBsMUliQgpqQZGseW7e/KPCeje3b64uyhpfq zppri5nJujl3tces0/VaSkN//enopMpX8K840N5V+434qxbu0s3jn/znvXtMXLwrUiBRP3Lt7 xa1nxohP/XvjP/MN29bYo40qPxRFf1zKv/Bdpc+7Ru7npOw8cnmgyVdP8S6mm6vTe6RkWZ1o4 +258fHH3su2pYCWW4oxEQy3mouJEAOzuai1pAgAA X-Env-Sender: julien.grall@arm.com X-Msg-Ref: server-9.tower-206.messagelabs.com!1469031101!50679772!1 X-Originating-IP: [217.140.101.70] X-SpamReason: No, hits=0.0 required=7.0 tests= X-StarScan-Received: X-StarScan-Version: 8.77; banners=-,-,- X-VirusChecked: Checked Received: (qmail 58188 invoked from network); 20 Jul 2016 16:11:41 -0000 Received: from foss.arm.com (HELO foss.arm.com) (217.140.101.70) by server-9.tower-206.messagelabs.com with SMTP; 20 Jul 2016 16:11:41 -0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id E520CBFA; Wed, 20 Jul 2016 09:12:51 -0700 (PDT) Received: from e108454-lin.cambridge.arm.com (e108454-lin.cambridge.arm.com [10.1.218.32]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 42FEB3F387; Wed, 20 Jul 2016 09:11:40 -0700 (PDT) From: Julien Grall To: xen-devel@lists.xen.org Date: Wed, 20 Jul 2016 17:10:56 +0100 Message-Id: <1469031064-23344-15-git-send-email-julien.grall@arm.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1469031064-23344-1-git-send-email-julien.grall@arm.com> References: <1469031064-23344-1-git-send-email-julien.grall@arm.com> Cc: proskurin@sec.in.tum.de, Julien Grall , sstabellini@kernel.org, wei.chen@linaro.org, steve.capper@arm.com Subject: [Xen-devel] [PATCH 14/22] xen/arm: p2m: Switch the p2m lock from spinlock to rwlock X-BeenThere: xen-devel@lists.xen.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: xen-devel-bounces@lists.xen.org Sender: "Xen-devel" P2M reads do not require to be serialized. This will add contention when PV drivers are using multi-queue because parallel grant map/unmaps/copies will happen on DomU's p2m. Signed-off-by: Julien Grall --- I have not done benchark to verify the performance, however a rwlock is always an improvement compare to a spinlock when most of the access only read data. It might be possible to convert the rwlock to a per-cpu rwlock which show some improvement on x86. --- xen/arch/arm/p2m.c | 12 ++++++------ xen/include/asm-arm/p2m.h | 3 ++- 2 files changed, 8 insertions(+), 7 deletions(-) diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c index d74c249..6136767 100644 --- a/xen/arch/arm/p2m.c +++ b/xen/arch/arm/p2m.c @@ -49,27 +49,27 @@ static bool_t p2m_mapping(lpae_t pte) static inline void p2m_write_lock(struct p2m_domain *p2m) { - spin_lock(&p2m->lock); + write_lock(&p2m->lock); } static inline void p2m_write_unlock(struct p2m_domain *p2m) { - spin_unlock(&p2m->lock); + write_unlock(&p2m->lock); } static inline void p2m_read_lock(struct p2m_domain *p2m) { - spin_lock(&p2m->lock); + read_lock(&p2m->lock); } static inline void p2m_read_unlock(struct p2m_domain *p2m) { - spin_unlock(&p2m->lock); + read_unlock(&p2m->lock); } static inline int p2m_is_locked(struct p2m_domain *p2m) { - return spin_is_locked(&p2m->lock); + return rw_is_locked(&p2m->lock); } void p2m_dump_info(struct domain *d) @@ -1389,7 +1389,7 @@ int p2m_init(struct domain *d) struct p2m_domain *p2m = &d->arch.p2m; int rc = 0; - spin_lock_init(&p2m->lock); + rwlock_init(&p2m->lock); INIT_PAGE_LIST_HEAD(&p2m->pages); p2m->vmid = INVALID_VMID; diff --git a/xen/include/asm-arm/p2m.h b/xen/include/asm-arm/p2m.h index 20a220ea..abda70c 100644 --- a/xen/include/asm-arm/p2m.h +++ b/xen/include/asm-arm/p2m.h @@ -3,6 +3,7 @@ #include #include +#include #include /* for vm_event_response_t */ #include #include @@ -20,7 +21,7 @@ extern void memory_type_changed(struct domain *); /* Per-p2m-table state */ struct p2m_domain { /* Lock that protects updates to the p2m */ - spinlock_t lock; + rwlock_t lock; /* Pages used to construct the p2m */ struct page_list_head pages;