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 085DB185958; Sun, 1 Sep 2024 16:45:26 +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=1725209127; cv=none; b=iMTi1B1DiHx2/wECcud27DwE17fDoCAUwAl6Ocppq9AXm1Hfb4759XHdZdLnN/idPki93msbLy0UW/tAIqaoEOBVJmcgqMhL69NvZ7jmOZ2eUBqH0oqvVC26ofL965DonSkTFjBb2FaAzQIhxmnbiugurtsEsqaI2p59e3d2TmE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725209127; c=relaxed/simple; bh=okG9X9ptlte5a9gfZLGYOhWJ5ByaCgp0PUylW8fCtj4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=HBXRU0J9InkxAKFW3NTjB5WRyGjSfIgui9Waqh7SCoVQ5YZ79Vsf5wRjWh2EWCailD7BTizJwu6wrVuXNkgfBFUuoqxKsTwsacFFL1W6u3WHeRHLc7JIo7fxORkiJgPVq7O4wqSVapl5VfB/saEBhZfqYiAwFgSI75NkGtRbRxw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=2Hu7oCs7; 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="2Hu7oCs7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2D560C4CEC3; Sun, 1 Sep 2024 16:45:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1725209126; bh=okG9X9ptlte5a9gfZLGYOhWJ5ByaCgp0PUylW8fCtj4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2Hu7oCs7NgmLRmWGry0CVckgIEIlzsLpiXeT5oPsmgatEIQhs52EUHuSf2zuuVJ3t Hue1GIBlOlwObkd8bdWtj2VJdu9z6UrEXwZr5N/vmSoUB+nvxZXlsXh2B6MO7g3Ryd w7E87car7o/dT1iY3uWUyhMzyFOYMts9KF9tJpIM= 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 5.4 121/134] net: busy-poll: use ktime_get_ns() instead of local_clock() Date: Sun, 1 Sep 2024 18:17:47 +0200 Message-ID: <20240901160814.635230325@linuxfoundation.org> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240901160809.752718937@linuxfoundation.org> References: <20240901160809.752718937@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.4-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 16258c0c7319e..36259516ec0d2 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