From patchwork Fri May 5 09:40:09 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joonas Lahtinen X-Patchwork-Id: 9713223 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 7C58260387 for ; Fri, 5 May 2017 09:40:21 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 82B77286BC for ; Fri, 5 May 2017 09:40:21 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6C6E428630; Fri, 5 May 2017 09:40:21 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 0435F28630 for ; Fri, 5 May 2017 09:40:21 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 337E16E615; Fri, 5 May 2017 09:40:19 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by gabe.freedesktop.org (Postfix) with ESMTPS id 044B36E615 for ; Fri, 5 May 2017 09:40:16 +0000 (UTC) Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga105.fm.intel.com with ESMTP; 05 May 2017 02:40:16 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos; i="5.38,291,1491289200"; d="scan'208"; a="1164975427" Received: from jlahtine-desk.ger.corp.intel.com ([10.252.14.94]) by fmsmga002.fm.intel.com with ESMTP; 05 May 2017 02:40:14 -0700 From: Joonas Lahtinen To: Intel graphics driver community testing & development Date: Fri, 5 May 2017 12:40:09 +0300 Message-Id: <1493977209-10970-1-git-send-email-joonas.lahtinen@linux.intel.com> X-Mailer: git-send-email 2.7.4 Cc: Andrea Arcangeli , "J . R . Okajima" Subject: [Intel-gfx] [PATCH] drm/i915: Do not sync RCU during shrinking X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" X-Virus-Scanned: ClamAV using ClamSMTP Due to the complex dependencies between workqueues and RCU, which are not easily detected by lockdep, do not synchronize RCU during shrinking. RCU sync gains us very little benefit in real life scenarios where the amount of memory used by object backing storage is dominant over the metadata under RCU. Suggested-by: Chris Wilson Signed-off-by: Joonas Lahtinen Cc: Chris Wilson Cc: Tvrtko Ursulin Cc: J. R. Okajima Cc: Andrea Arcangeli Reviewed-by: Chris Wilson --- drivers/gpu/drm/i915/i915_gem_shrinker.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem_shrinker.c b/drivers/gpu/drm/i915/i915_gem_shrinker.c index 0e7352d..e1868ed 100644 --- a/drivers/gpu/drm/i915/i915_gem_shrinker.c +++ b/drivers/gpu/drm/i915/i915_gem_shrinker.c @@ -59,9 +59,6 @@ static void shrinker_unlock(struct drm_i915_private *dev_priv, bool unlock) return; mutex_unlock(&dev_priv->drm.struct_mutex); - - /* expedite the RCU grace period to free some request slabs */ - synchronize_rcu_expedited(); } static bool any_vma_pinned(struct drm_i915_gem_object *obj)