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[98.225.44.182]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-38e172b6da2sm3320825a91.4.2026.07.15.07.42.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Jul 2026 07:42:51 -0700 (PDT) Date: Wed, 15 Jul 2026 07:42:48 -0700 From: Stanislav Kinsburskii To: "David Hildenbrand (Arm)" Cc: airlied@gmail.com, akhilesh@ee.iitb.ac.in, akpm@linux-foundation.org, corbet@lwn.net, dakr@kernel.org, jgg@ziepe.ca, kees@kernel.org, leon@kernel.org, liam@infradead.org, lizhi.hou@amd.com, ljs@kernel.org, lyude@redhat.com, maarten.lankhorst@linux.intel.com, mamin506@gmail.com, mhocko@suse.com, mripard@kernel.org, nouveau@lists.freedesktop.org, ogabbay@kernel.org, oleg@redhat.com, rppt@kernel.org, shuah@kernel.org, simona@ffwll.ch, skhan@linuxfoundation.org, surenb@google.com, tzimmermann@suse.de, vbabka@kernel.org, dri-devel@lists.freedesktop.org, linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-rdma@vger.kernel.org Subject: Re: [PATCH v2 0/4] mm/hmm: Clarify notifier retry state and scope HMM timeouts Message-ID: References: <178406760622.1106335.2379450382728057793.stgit@skinsburskii> <4300f09b-8f93-4605-b072-7c09a82cb16e@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <4300f09b-8f93-4605-b072-7c09a82cb16e@kernel.org> X-Stat-Signature: mhwpei7igwgtfbsgq34mkketk3ox5o5i X-Rspamd-Queue-Id: EC36E14000E X-Rspam-User: X-Rspamd-Server: rspam07 X-HE-Tag: 1784126572-898805 X-HE-Meta: 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 vIEf9Ji6 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Jul 15, 2026 at 02:41:43PM +0200, David Hildenbrand (Arm) wrote: > On 7/15/26 00:21, Stanislav Kinsburskii wrote: > > This small fixup series applies on top of: > > > > [PATCH v8 0/8] mm/hmm: Add mmap lock-drop support for userfaultfd-backed mappings > > > > The first patch updates the HMM documentation example to make the > > mmu_interval_read_retry() state explicit: callers should use the notifier and > > notifier_seq stored in the same hmm_range that was passed to > > hmm_range_fault_unlocked_timeout(). > > > > The remaining patches adjust nouveau, amdxdna, and drm_gpusvm users so the > > timeout passed to hmm_range_fault_unlocked_timeout() is treated as a relative > > HMM retry budget. These callers no longer keep an absolute deadline around > > their outer driver retry loops or pass a computed remaining time into HMM. > > > > This keeps the timeout scoped to HMM's internal mmu-notifier retry handling. If > > HMM succeeds and the driver later observes an invalidation through > > mmu_interval_read_retry(), the driver retries the operation with a fresh HMM > > retry budget. > > > > Changes in v2: > > - Kept the nouveau outer absolute timeout around the > > mmu_interval_read_retry() loop. hmm_range_fault_unlocked_timeout() only > > bounds HMM’s internal retries, while nouveau faults are handled from a GPU > > fault worker, so userspace fatal signals cannot break an endless stream of > > invalidations there. > > - Updated nouveau to use time_after_eq() before calling HMM, so the remaining > > timeout passed to hmm_range_fault_unlocked_timeout() is always positive and > > never 0, which would mean retry indefinitely. > > - Updated the nouveau fixup commit message to explain the worker-thread > > timeout issue and the time_after_eq() boundary behavior. > > - Fixed the amdxdna fixup commit message. It now describes > > aie2_populate_range() correctly instead of carrying stale nouveau prose, > > and notes that command submission still keeps its broader timeout while HMM > > gets a fresh relative retry budget. > > > > > > --- > > > > Stanislav Kinsburskii (4): > > fixup! mm/hmm: add hmm_range_fault_unlocked_timeout() for mmap lock-drop support > > fixup! drm/nouveau: use hmm_range_fault_unlocked_timeout() for SVM faults > > fixup! accel/amdxdna: use hmm_range_fault_unlocked_timeout() for range population > > fixup! drm/gpusvm: use hmm_range_fault_unlocked_timeout() for range faults > > Why a fixup series instead of properly resending the full thing? > The goal was to get a Sashiko review, and v8 has already been applied to both `mm-new` and `linux-next`. You can find more details here: https://sashiko.dev/#/message/alaWmUEeIBeSkmO0%40skinsburskii Thanks, Stanislav > -- > Cheers, > > David