From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 41CEB193064 for ; Tue, 26 Nov 2024 11:49:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732621758; cv=none; b=g9ev6+yhasYcuMsdP4vsiSYwwTNE7L/gpzgGeeyt+fpKdxTEULKqHkhOcA8PR3ofCRZnFt0HvNik5b/+1hZ1hjWLXUAlKZMFvJV+Xg+Y6G8iwm4EkIjUGPAuq11LanLvVhP2hJQBRoZgLF7xlkwiSw37iUAsA5fADUxFxJoIBXc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732621758; c=relaxed/simple; bh=f58et2nyreK+xJUisiVXOOdinhTznscj3Lig6FTrUJ4=; h=Message-ID:Date:MIME-Version:Subject:To:References:From: In-Reply-To:Content-Type; b=tydfgI/aDWHyVqstlx5irGkUXXm9xwY4G9QwSRq9EdPkPb3X72mI5QW+8mh3GPEXTeY4kHOZpfb61q+dKFiVasUtMwHx1PzXpT31A/DwhHSc6F7c87jHxYJcCRLS7CTLF/azUCRFeRcXx3FPYKzvxlXvZK80i5+H7m7c/MS4pio= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 91D841682; Tue, 26 Nov 2024 03:49:39 -0800 (PST) Received: from [10.1.196.40] (e121345-lin.cambridge.arm.com [10.1.196.40]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D82D43F58B; Tue, 26 Nov 2024 03:49:08 -0800 (PST) Message-ID: <84cb9155-4793-45f9-bb67-6926e103dc84@arm.com> Date: Tue, 26 Nov 2024 11:49:06 +0000 Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] iommu: Downgrade print level for iommu group information To: Li RongQing , joro@8bytes.org, will@kernel.org, iommu@lists.linux.dev References: <20241126072339.25714-1-lirongqing@baidu.com> From: Robin Murphy Content-Language: en-GB In-Reply-To: <20241126072339.25714-1-lirongqing@baidu.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 26/11/2024 7:23 am, Li RongQing wrote: > This per device log is becoming longer with more and more PCI devices > in system, which slows down the boot process due to the serializing > nature of printk(). > > Downgrade dev_info() to dev_dbg() so it is still accessible for debug > purposes. Previously discussed 4 and a half years ago: https://lore.kernel.org/linux-iommu/20200302154426.GC6540@8bytes.org/ Also, given that the iommu_probe_device() path is inherently serialised anyway, if logging a message from there significantly slows down your boot process, how slow is your console device? Thanks, Robin. > Signed-off-by: Li RongQing > --- > drivers/iommu/iommu.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index 83c8e61..a16f944 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -1193,7 +1193,7 @@ static struct group_device *iommu_group_alloc_device(struct iommu_group *group, > > trace_add_device_to_group(group->id, dev); > > - dev_info(dev, "Adding to iommu group %d\n", group->id); > + dev_dbg(dev, "Adding to iommu group %d\n", group->id); > > return device; >