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charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.56.2 (3.56.2-2.fc42) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Sat, 2026-06-20 at 17:08 -0700, Ashok Raj wrote: >=20 > =C2=A0 If remove_iova() keeps failing (mas_store_gfp(NULL, GFP_ATOMIC) > still > =C2=A0 can't get a maple tree node), the iova is pushed back onto > deferred_frees > =C2=A0 and the work reschedules itself at a flat 10ms =E2=80=94 forever.= =C2=A0 There is > no > =C2=A0 retry counter or no backoff. >=20 > =C2=A0 Under sustained memory pressure a device doing frequent unmap coul= d > =C2=A0 accumulate a growing deferred list, exhaust its IOVA space, and > start > =C2=A0 failing DMA map calls =E2=80=94 with nothing in dmesg pointing at = the real > cause. >=20 To some extent, yes. However, if we have GFP_ATOMIC allocations continue to fail for several seconds, the system will be in much larger trouble. Making the condition visible seems like a good idea, since I don't know if the other GFP_ATOMIC paths that could cause system hangs output any warnings. --=20 All Rights Reversed.