From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-dl1-f51.google.com (mail-dl1-f51.google.com [74.125.82.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 299A53C0603 for ; Tue, 7 Apr 2026 15:31:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.82.51 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775575893; cv=none; b=TPcQu+UFHlEKQIrH6kN5QZDR2lDYQL7ggysPPFxbjVrXH7dqCuT2LCm+1yby/P+KghrDfocupBlTb7vLCT5LQWeo+AycLTRNh1tJmEfVcjThv2y6Tdg7ZiLNsQlyjxL1Z4lmdoIxTVPkm1CDygZ0alJYJO0IyqzJfjWEPGEPg8c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775575893; c=relaxed/simple; bh=RQc8d8POo53za1btklrzd2j41bVBDu/kMc2J8CQXhJw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=BL4UQlC0G84fcU1VC7PegAvavokIpKAMo31IMDv8a7h4ujAIArxxiSogoEB5MG1CHji/hqIYTQF6yWmW28kZ/4Fd7vBaGY9fFiZ4WuFY7CtU3dvFcDcVmPXWgCGZ5QDIzszXQLsMDIaEjCWp7G8aIsPDG6I99ry3EYHwTf+GLzo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=cgoUmKdj; arc=none smtp.client-ip=74.125.82.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="cgoUmKdj" Received: by mail-dl1-f51.google.com with SMTP id a92af1059eb24-126ea4e9697so35288c88.1 for ; Tue, 07 Apr 2026 08:31:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1775575881; x=1776180681; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=5fjyrHqf2RDTN165o9RX7THJTFjmJJ5U4Jjhs69/SOU=; b=cgoUmKdjvOkhZ57XZ45w2vRyEr77yIursGlLmdR4h/mCmHWWpWQS/h2TGk8TySVh1k v2a8gTK6epOvemJdgWFyxXjCSI7/XxAzzWDwr6lBNPjqlTieihFGBmsaMwtQqBiMHgWH v+DkBMXVWJRaYb5PABc/TuumWy5bqZYAGDkLuWerqWIwDtTinPSdvtRNg+sSSxb4Bbj9 aRVznxOGFDRwAijO7XWrFkWaaV9vNcMp1FnhlhB/6GbxYR4nbZa53MVlggGbm+FitEOW Sl0U0UGT35hT1OxI2bHzEGuuAionxTuYR5xnoXj9tCuZScehj1+URZbRhnDqE85J+mWo 5+6g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1775575881; x=1776180681; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=5fjyrHqf2RDTN165o9RX7THJTFjmJJ5U4Jjhs69/SOU=; b=E+yIga4nE5Yp8b1jaunJLL/kBIn9nDqEg2OfMWWzrTPUNq231H5T2PrNnx7QF+uHpt sAcPqlqT4jz0YYVcEwUYpVGayc2Lz8YSkEwLBtLrbIi4FJZOr0t3zVzz7+Cvm4Nkwgo0 vo5XDEUDnSFiR0pegQCF/pu5sxxGRYm/5lePTYmqtDc/lkvTPje6agfQEdPM3W6bWQql 9GddbYOKQZBvrK4YkwHKNrBiR+9yv+Ns3jvutrDO/1vrlArSueYtfxfp9NKwfGZsTdkd FZRMEEODFZBlLW3VuSmVA9PR+ui7x+TXDUIYLdyII9HaqGJdbjkc961NF8WuckxT94N+ UxtQ== X-Forwarded-Encrypted: i=1; AJvYcCVXJ/5T4IQa24h1tGzDYZulYRToTN3v4Mf60D+ghle3UKJHJqzxI3e0HNFjEZBbo+FiTa1eyXmYErxNAls=@vger.kernel.org X-Gm-Message-State: AOJu0YzhOjDTQLfKsfiL8YWp6aXnc1PEFyh2C89gRPMKJjpmEmEUBEyR SFssChbOfUI28x1NR1Tm30QLe1Rw4AP4dpsO+V3wZY6W1ITZ4C7VNDCrwFpMUDp68w== X-Gm-Gg: AeBDieuhRxpG6OJlI7qqzRmCYkxVS/4TfyGj37irlQevLSAGongJHLMFo1VAOGy7cnP LEmctQq9PdVoA1ft1pAc11TjjY2OHX0CVTVeat3etETsEYAijs8+ZEoT0cS5nyZmbVdF7AGJAyp k6yMKrttlwPRh/q5p4bRSTC4X/CNGYyS4Zt+Yr6Cth8eEuQH+xb5NNQyCWoXEgQl5hovya6JQ1f 58IVvOYFu0o9uRCDgHKhaLQVMA+BBZvV3RrHkM3RiNAWHhnpEmpRDNd3lAglHmzpuemOIJf0ZIy OIKQO+LzTQ0WSdTcarHnK7o5wHnccwFBBPyk03HGtFH/xJhFjQcmOeIilHxCsLOxLm9ufjiXwoC 5MeQLrqMk3K6k5B7PTF4h80gjdfQN+ypZMTmn/PMFC4P0zFFiz33pR+DxA0qtEwifsBfDt7cV6G HiyK72YsZ3nLIJCfHjFsUkiUu93qBZqV+6zPYWSWVYg5N2c89brnvmKyRORQ== X-Received: by 2002:a05:7022:618b:b0:12a:8cf4:65d8 with SMTP id a92af1059eb24-12bfbc17168mr462147c88.14.1775575880307; Tue, 07 Apr 2026 08:31:20 -0700 (PDT) Received: from google.com (174.188.87.34.bc.googleusercontent.com. [34.87.188.174]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-2d1bf4447dasm2731746eec.21.2026.04.07.08.31.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 07 Apr 2026 08:31:19 -0700 (PDT) Date: Tue, 7 Apr 2026 15:31:14 +0000 From: Pranjal Shrivastava To: Lin Ruifeng Cc: joro@8bytes.org, will@kernel.org, robin.murphy@arm.com, jroedel@suse.de, iommu@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH] iommu: Use dev_dbg for group handling code Message-ID: References: <20260407130638.1920205-1-linruifeng4@huawei.com> Precedence: bulk X-Mailing-List: linux-kernel@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: <20260407130638.1920205-1-linruifeng4@huawei.com> On Tue, Apr 07, 2026 at 09:06:38PM +0800, Lin Ruifeng wrote: > When devices are frequently registered/unregistered, there will be a large > number of iommu group adding/remove messages, which will flood the dmesg buffer > and flush out other logs. For iommu group handling messages, we can use dev_dbg > to output logs only when needed. > > Signed-off-by: Lin Ruifeng > --- > drivers/iommu/iommu.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index 50718ab810a4..18ceaba6cf0a 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -1283,7 +1283,7 @@ 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; > > @@ -1337,7 +1337,7 @@ void iommu_group_remove_device(struct device *dev) > if (!group) > return; > > - dev_info(dev, "Removing from iommu group %d\n", group->id); > + dev_dbg(dev, "Removing from iommu group %d\n", group->id); > > __iommu_group_remove_device(dev); > } I believe this was discussed roughly an year ago as well: https://lore.kernel.org/linux-iommu/84cb9155-4793-45f9-bb67-6926e103dc84@arm.com/ And 5 years ago as well: https://lore.kernel.org/linux-iommu/20200302154426.GC6540@8bytes.org/ The general consensus is that the maintainers and the community would like to keep this log in place as it helps us debug issues just based on dmesg logs shared over an email. I understand that losing dmesg logs in such situations could be frustrating but I guess you could try increasing the log buffer size.. Thanks, Praan