From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 D98C9181334; Sun, 1 Sep 2024 16:56:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725209770; cv=none; b=f8nFIylcJPAUHqGgmz/jbvhyXSpneYJmPyhOWN0Xwt4ho9soQW1PAIAOejgQme8TLQ4VS898XFzsLnVmyqLPeva4ti5gKaoltqShfwuF3pKFKrgwB07McwBLyk7z+6tbmHQq7LHjPSJMA8dCEVTXagEp3q/Ed3Bf94dzEdaCKPo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725209770; c=relaxed/simple; bh=g7+eWRfHdW/lDABwU/suSHqO6GaFeS82RpjZVHPMZ30=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=X9X2InL7QcXyPYDOUiL+R4d8fqfKEYvycfJKzFcY7Lr2CyAmFiGBZtVazBCNyGBJ9qrS+5bOsaYght6pL+DfFCLO/ajz7oXRfKIBzU9EGdCfBdS3EuLKZXRkXAWrBC0bc7rv4Y1WVcQu63yXJHZu4ZgPiW3Q/dWPHDhYSUgTYks= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=VKopTk0u; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="VKopTk0u" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 465E2C4CEC3; Sun, 1 Sep 2024 16:56:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1725209770; bh=g7+eWRfHdW/lDABwU/suSHqO6GaFeS82RpjZVHPMZ30=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VKopTk0uh2J5RZ6ruNaYSLfhVPSBTEYVFSALyASYjQNIO9dL0zCPNGBVpMkrpg+C7 Sh4mh8pEKArapvsNqeqvV2WzA/tjKlqv4oqAbY+ss+6HSxBH69/72Niy6TP/aJO789 tNgz0m+hlKGVkQNJWBuwttIwC04OtBZm1MiB3X1k= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , Mina Almasry , Willem de Bruijn , Joe Damato , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.10 140/151] net: busy-poll: use ktime_get_ns() instead of local_clock() Date: Sun, 1 Sep 2024 18:18:20 +0200 Message-ID: <20240901160819.374454433@linuxfoundation.org> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240901160814.090297276@linuxfoundation.org> References: <20240901160814.090297276@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 0870b0d8b393dde53106678a1e2cec9dfa52f9b7 ] Typically, busy-polling durations are below 100 usec. When/if the busy-poller thread migrates to another cpu, local_clock() can be off by +/-2msec or more for small values of HZ, depending on the platform. Use ktimer_get_ns() to ensure deterministic behavior, which is the whole point of busy-polling. Fixes: 060212928670 ("net: add low latency socket poll") Fixes: 9a3c71aa8024 ("net: convert low latency sockets to sched_clock()") Fixes: 37089834528b ("sched, net: Fixup busy_loop_us_clock()") Signed-off-by: Eric Dumazet Cc: Mina Almasry Cc: Willem de Bruijn Reviewed-by: Joe Damato Link: https://patch.msgid.link/20240827114916.223377-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- include/net/busy_poll.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/net/busy_poll.h b/include/net/busy_poll.h index 36e5e75e71720..be01eda3b6ff7 100644 --- a/include/net/busy_poll.h +++ b/include/net/busy_poll.h @@ -61,7 +61,7 @@ static inline bool sk_can_busy_loop(struct sock *sk) static inline unsigned long busy_loop_current_time(void) { #ifdef CONFIG_NET_RX_BUSY_POLL - return (unsigned long)(local_clock() >> 10); + return (unsigned long)(ktime_get_ns() >> 10); #else return 0; #endif -- 2.43.0