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 B27672EAD15; Wed, 25 Feb 2026 18:10:58 +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=1772043058; cv=none; b=u6uz4LWewhn/xl47Mhz7Z3d36ROwTtyn92NdP3Iu7Rz1+KQhApf7id2x94zWmxdalCKhL2qds8eTVafhapSqO9hCIo5Dr11XTnpCCYSYMxXyS4V0cnrFweO9Sb2vvZ12yOy9Z/WPEWs8usR+ciZkyoNuFPbnLy/HBDqLPXzL9jk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772043058; c=relaxed/simple; bh=aGEZjMc+9o4fu9fekWMA3ubb1LICyq926GnBRIV25JE=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; b=VymN70Jw86ljuCf4SkPX07rWQXP/5CXTwW78KQtoGmR7Xisu73n8II0P/SOyBVhSn6n5yjoa6VlAnxddEaYmIH99EZXtRchhsdhNpGE/JfCKFRzD0gRMUQixFv7SXMUB8Syq38SLp0UJNEybRrEz+xCqqcMgiNoPzkZ3eh6rBAQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=D3bkB9Im; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="D3bkB9Im" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 35AF1C19422; Wed, 25 Feb 2026 18:10:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772043058; bh=aGEZjMc+9o4fu9fekWMA3ubb1LICyq926GnBRIV25JE=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=D3bkB9Im3rEUTJTxcWfIcIQEKDlqPwJ7gtno3YLieVu02v8iI352sSe39JVUqfQHn +9tMy+lTmfFL9XTPJK2j3btKaZIoc64KQ57eLpMDMzQV1fcQtg6IX0i8zKsalxAMQd ovb1rkObfoAsHv5FU1qEy4Ti2o2gABG2DIEuEtTOAXSXPD8H6o1HCY7flDKU1WenOT YevCFKZwct/fUD4exM1TddPzBk98wNujLwuBoTiYkziTRcLHxcrl/hzuC9X5TjGFVi LjnBBppEfGIgxPJjGD9ETyem/k3K2gCqfU8RuvR+i+fYy+YHghpbZOKptbs6Tc8UWH dsal27yeNSiKw== Date: Wed, 25 Feb 2026 12:10:56 -0600 From: Bjorn Helgaas To: Hongyu Xie Cc: bhelgaas@google.com, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RESEND PATCH v1] PCI: replace msleep to save waiting time Message-ID: <20260225181056.GA3779670@bhelgaas> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260223061919.1408000-1-xiehongyu1@kylinos.cn> On Mon, Feb 23, 2026 at 02:19:19PM +0800, Hongyu Xie wrote: > In pcie_wait_for_link_status, using msleep(1) to wait for link status > change. > But msleep(1) can sleep for nearly 5ms. > > ftrace shows: > 0) | pcie_wait_for_link_status() { > 0) 0.500 us | pcie_capability_read_word(); > 0) 0.580 us | pcie_capability_read_word(); > 0) * 10292.26 us | } > > after changing to usleep_range. > ftrace shows: > > 0) | pcie_wait_for_link_status() { > 0) 0.320 us | pcie_capability_read_word(); > 0) 0.480 us | pcie_capability_read_word(); > 0) # 2483.980 us | } > > So fix this by using usleep_range. > > Signed-off-by: Hongyu Xie > --- > drivers/pci/pci.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index f3244630bfd0..68532e248e51 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -4519,7 +4519,7 @@ static int pcie_wait_for_link_status(struct pci_dev *pdev, > pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnksta); > if ((lnksta & lnksta_mask) == lnksta_match) > return 0; > - msleep(1); > + usleep_range(1000, 1100); Perhaps consider fsleep(), since it's a little more generic and I don't think there's anything magic about the 100 us range value. > } while (time_before(jiffies, end_jiffies)); > > return -ETIMEDOUT; > -- > 2.25.1 >