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[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: iommu@lists.linux.dev 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