From patchwork Tue Nov 5 18:30:40 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Haris Okanovic X-Patchwork-Id: 13863353 Received: from smtp-fw-52003.amazon.com (smtp-fw-52003.amazon.com [52.119.213.152]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 96E751E883C; Tue, 5 Nov 2024 18:32:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=52.119.213.152 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730831546; cv=none; b=JRtRP2+6cip4BQzXwWdu9Zr5Bii+EX95ADRG/97XPUxbj32SVqzeMRrCOwsJGtM74Ykk0Z5F0G9fnJYupue1wIJPnmIhR1Gs1sad3Q9zSaW1DSqMsVR2lEjTGilSiP7uOUbcUq5xXXXWavpddYJCsI22j5F/yvI9dPdo9+g3UBI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730831546; c=relaxed/simple; bh=t30kpWj2OTYiI0ATHwleBX8+0AO3huVHiGER9YBLofI=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=AqcRBpYMb3ONmuk6k4aq7nEsSc5qnsjGKohuglcCK/m+I7U/E+oqcFu+eCzCdQZLZPxF/FWsm05uPxhqZ2Cx75pmMW6otzBNBj+OK2k3Kos7kIbRAU9U8Vl5rpT9wKT8Cd3d1WR0paGJVL7+JYV/5dDNpKgqVzguOQhU/32UmDo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com; spf=pass smtp.mailfrom=amazon.com; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b=b+HLuqkI; arc=none smtp.client-ip=52.119.213.152 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=amazon.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="b+HLuqkI" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1730831545; x=1762367545; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=XT81pCaCySeLSnjYgvTXLKqn2CWQcbY+GGEiD2145i8=; b=b+HLuqkI6efbI3OfXxaTDfb5pZFHTIBpnkhuvXTNf5K40swCwvv4i/lK OFl7c3vOX6Sv9TxYganTszklnckbLLZnDCtT5sL8e4qNjGqI7FG2AovFn MUmkOEu0UQ5ZfFh+ZFu6OCnu4j7cK3bS/7/9361OG6rnFa4moeMEurRHf I=; X-IronPort-AV: E=Sophos;i="6.11,260,1725321600"; d="scan'208";a="39203526" Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO smtpout.prod.us-west-2.prod.farcaster.email.amazon.dev) ([10.43.8.6]) by smtp-border-fw-52003.iad7.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Nov 2024 18:32:22 +0000 Received: from EX19MTAUWC001.ant.amazon.com [10.0.7.35:25778] by smtpin.naws.us-west-2.prod.farcaster.email.amazon.dev [10.0.63.130:2525] with esmtp (Farcaster) id fb722a64-c7d9-4601-a9fb-a5752e9890eb; Tue, 5 Nov 2024 18:32:20 +0000 (UTC) X-Farcaster-Flow-ID: fb722a64-c7d9-4601-a9fb-a5752e9890eb Received: from EX19D001UWA003.ant.amazon.com (10.13.138.211) by EX19MTAUWC001.ant.amazon.com (10.250.64.174) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1258.34; Tue, 5 Nov 2024 18:32:20 +0000 Received: from u34cccd802f2d52.amazon.com (10.106.239.17) by EX19D001UWA003.ant.amazon.com (10.13.138.211) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1258.35; Tue, 5 Nov 2024 18:32:15 +0000 From: Haris Okanovic To: , CC: , , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [PATCH 4/5] arm64: add smp_vcond_load_relaxed() Date: Tue, 5 Nov 2024 12:30:40 -0600 Message-ID: <20241105183041.1531976-5-harisokn@amazon.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20241105183041.1531976-1-harisokn@amazon.com> References: <20240925232425.2763385-1-ankur.a.arora@oracle.com> <20241105183041.1531976-1-harisokn@amazon.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: EX19D033UWA004.ant.amazon.com (10.13.139.85) To EX19D001UWA003.ant.amazon.com (10.13.138.211) Implement smp_vcond_load_relaxed() atop __delay_until_ul() on arm64, to reduce number of busy loops while waiting for a value condition. This implementation only support unsigned long words. It can be extended via the enclosed case structure in barrier.h as needed. Signed-off-by: Haris Okanovic --- arch/arm64/include/asm/barrier.h | 18 ++++++++++++++++++ arch/arm64/lib/delay.c | 16 ++++++++++++++++ 2 files changed, 34 insertions(+) diff --git a/arch/arm64/include/asm/barrier.h b/arch/arm64/include/asm/barrier.h index 1ca947d5c939..188327e3ce72 100644 --- a/arch/arm64/include/asm/barrier.h +++ b/arch/arm64/include/asm/barrier.h @@ -203,6 +203,24 @@ do { \ (typeof(*ptr))VAL; \ }) +extern unsigned long __smp_vcond_load_relaxed_ul( + u64 nsecs, unsigned long* addr, unsigned long mask, unsigned long val); + +#define smp_vcond_load_relaxed(nsecs, addr, mask, val) ({ \ + u64 __nsecs = (nsecs); \ + typeof(addr) __addr = (addr); \ + typeof(*__addr) __mask = (mask); \ + typeof(*__addr) __val = (val); \ + typeof(*__addr) __cur; \ + switch (sizeof(*__addr)) { \ + case sizeof(unsigned long): \ + __cur = __smp_vcond_load_relaxed_ul( \ + __nsecs, __addr, __mask, __val); \ + break; \ + } \ + (__cur); \ +}) + #define smp_cond_load_acquire(ptr, cond_expr) \ ({ \ typeof(ptr) __PTR = (ptr); \ diff --git a/arch/arm64/lib/delay.c b/arch/arm64/lib/delay.c index a7c3040af316..a61a13b04439 100644 --- a/arch/arm64/lib/delay.c +++ b/arch/arm64/lib/delay.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include @@ -97,3 +98,18 @@ void __ndelay(unsigned long nsecs) __delay(NSECS_TO_CYCLES(nsecs)); } EXPORT_SYMBOL(__ndelay); + +unsigned long __smp_vcond_load_relaxed_ul( + u64 nsecs, unsigned long* addr, unsigned long mask, unsigned long val) +{ + const u64 start = local_clock_noinstr(); + const u64 cycles = NSECS_TO_CYCLES(nsecs); + unsigned long cur; + + do { + cur = __delay_until_ul(cycles, addr, mask, val); + } while((cur & mask) != val && local_clock_noinstr() - start < nsecs); + + return cur; +} +EXPORT_SYMBOL(__smp_vcond_load_relaxed_ul);