From patchwork Thu Jan 3 12:23:28 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tvrtko Ursulin X-Patchwork-Id: 10747265 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 652916C5 for ; Thu, 3 Jan 2019 12:23:41 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 54BD2285A2 for ; Thu, 3 Jan 2019 12:23:41 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 497902861D; Thu, 3 Jan 2019 12:23:41 +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=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, 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 EED1A285A2 for ; Thu, 3 Jan 2019 12:23:40 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 9BECF89D49; Thu, 3 Jan 2019 12:23:39 +0000 (UTC) X-Original-To: Intel-gfx@lists.freedesktop.org Delivered-To: Intel-gfx@lists.freedesktop.org Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by gabe.freedesktop.org (Postfix) with ESMTPS id 2CCC889BBD for ; Thu, 3 Jan 2019 12:23:36 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 03 Jan 2019 04:23:36 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,434,1539673200"; d="scan'208";a="308639870" Received: from unknown (HELO localhost.localdomain) ([10.252.3.166]) by fmsmga005.fm.intel.com with ESMTP; 03 Jan 2019 04:23:35 -0800 From: Tvrtko Ursulin To: Intel-gfx@lists.freedesktop.org Date: Thu, 3 Jan 2019 12:23:28 +0000 Message-Id: <20190103122329.19948-4-tvrtko.ursulin@linux.intel.com> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190103122329.19948-1-tvrtko.ursulin@linux.intel.com> References: <20190103122329.19948-1-tvrtko.ursulin@linux.intel.com> MIME-Version: 1.0 Subject: [Intel-gfx] [RFC 3/4] drm/i915: Return immediately if trylock fails for direct-reclaim X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" X-Virus-Scanned: ClamAV using ClamSMTP From: Tvrtko Ursulin In an equally named patch Chris Wilson proposes skipping the attempts to obtain struct_mutex via trylock-looping in order to improve latency for non-i915 clients. I quote: """ Ignore trying to shrink from i915 if we fail to acquire the struct_mutex in the shrinker while performing direct-reclaim. The trade-off being (much) lower latency for non-i915 clients at an increased risk of being unable to obtain a page from direct-reclaim without hitting the oom-notifier. The proviso being that we still keep trying to hard obtain the lock for oom so that we can reap under heavy memory pressure. """ This version of the patch does strictly what the commit message explains and leaves other changes out. Signed-off-by: Tvrtko Ursulin Cc: Chris Wilson --- drivers/gpu/drm/i915/i915_gem_shrinker.c | 30 ++++++++++++++---------- 1 file changed, 17 insertions(+), 13 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem_shrinker.c b/drivers/gpu/drm/i915/i915_gem_shrinker.c index 586acf02727e..97deec775f40 100644 --- a/drivers/gpu/drm/i915/i915_gem_shrinker.c +++ b/drivers/gpu/drm/i915/i915_gem_shrinker.c @@ -36,7 +36,8 @@ #include "i915_drv.h" #include "i915_trace.h" -static bool shrinker_lock(struct drm_i915_private *i915, bool *unlock) +static bool +shrinker_lock(struct drm_i915_private *i915, unsigned int flags, bool *unlock) { switch (mutex_trylock_recursive(&i915->drm.struct_mutex)) { case MUTEX_TRYLOCK_RECURSIVE: @@ -45,15 +46,17 @@ static bool shrinker_lock(struct drm_i915_private *i915, bool *unlock) case MUTEX_TRYLOCK_FAILED: *unlock = false; - preempt_disable(); - do { - cpu_relax(); - if (mutex_trylock(&i915->drm.struct_mutex)) { - *unlock = true; - break; - } - } while (!need_resched()); - preempt_enable(); + if (flags & I915_SHRINK_ACTIVE) { + preempt_disable(); + do { + cpu_relax(); + if (mutex_trylock(&i915->drm.struct_mutex)) { + *unlock = true; + break; + } + } while (!need_resched()); + preempt_enable(); + } return *unlock; case MUTEX_TRYLOCK_SUCCESS: @@ -160,7 +163,8 @@ i915_gem_shrink(struct drm_i915_private *i915, unsigned long scanned = 0; bool unlock = false; - if (!(flags & I915_SHRINK_LOCKED) && !shrinker_lock(i915, &unlock)) + if (!(flags & I915_SHRINK_LOCKED) && + !shrinker_lock(i915, flags, &unlock)) return 0; /* @@ -359,7 +363,7 @@ i915_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc) sc->nr_scanned = 0; - if (!shrinker_lock(i915, &unlock)) + if (!shrinker_lock(i915, flags, &unlock)) return SHRINK_STOP; freed = i915_gem_shrink(i915, @@ -393,7 +397,7 @@ shrinker_lock_uninterruptible(struct drm_i915_private *i915, bool *unlock, do { if (i915_gem_wait_for_idle(i915, 0, timeout) == 0 && - shrinker_lock(i915, unlock)) + shrinker_lock(i915, 0, unlock)) break; schedule_timeout_killable(1);