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Mon, 12 Oct 2026 23:07:49 +0000 X-Mizu-Trace-ID: 235e8c915f036f3a X-Migadu-Flow: FLOW_OUT Date: Mon, 12 Oct 2026 16:07:44 -0700 From: Shakeel Butt To: Peizhe Liu Cc: Joerg Roedel , Will Deacon , Robin Murphy , Lu Baolu , Jason Gunthorpe , Kevin Tian , Jean-Philippe Brucker , Johannes Weiner , Michal Hocko , Roman Gushchin , Muchun Song , iommu@lists.linux.dev, linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] iommu/sva: Charge IOPF allocations to the faulting mm's memcg Message-ID: References: <20261012200823.699316-1-peizheliu@utexas.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261012200823.699316-1-peizheliu@utexas.edu> X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: B801280008 X-Rspam-User: X-Stat-Signature: o5hiajrwxfzn8goozec64yut6p4rhb3n X-HE-Tag: 1791846471-668011 X-HE-Meta: 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 ira3dGb5 vKT/ZgdlenAKdKKXn2CJi92YvGcMqRgJgD7LvfWSpxVld6/qlSzqPNftSiWatlIAbx00KI8vam7m756fNoCfHobEvSjjqRwSG+oCtwTXQRdn6Ncx6q6m/vvLruPCe/NpVxWA1kJ86YDv+HCcQRnKkp6Qy2ORQ1sRJVQKpP33lGDjBcHZj93PvNWH999g6tgrrRM8dHzqua1MNWUK5AH0IFY+7+GQG5GBTB/3bfBvXbIVJ38OOW6Qn+RvLRbRnwQxWjJz75J3es3+LNrj5ykxm4OSaiw== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Oct 12, 2026 at 03:08:23PM -0500, Peizhe Liu wrote: > iommu_sva_handle_mm() runs from the IOPF workqueue and calls > handle_mm_fault() for the faulting mm, but does not set the active > memcg. File-backed faults can allocate page cache through > mem_cgroup_charge(folio, NULL, gfp), which falls back to the root memcg > when the worker has neither an active memcg nor a current->mm. Page > cache faulted in by a device is therefore charged to root and escapes > the task's memory.max. > > Set the active memcg to the one associated with the faulting mm while > handling the fault, and restore the previous value afterwards. > > Fixes: fc36479db74e ("iommu: Add a page fault handler") > Signed-off-by: Peizhe Liu This looks fine from memcg perspective. Reviewed-by: Shakeel Butt