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[98.225.44.182]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-ca5afbc1208sm8643053a12.9.2026.07.13.09.59.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 13 Jul 2026 09:59:19 -0700 (PDT) Date: Mon, 13 Jul 2026 09:59:17 -0700 From: Stanislav Kinsburskii To: Andrew Morton Cc: airlied@gmail.com, akhilesh@ee.iitb.ac.in, corbet@lwn.net, dakr@kernel.org, david@kernel.org, decui@microsoft.com, haiyangz@microsoft.com, jgg@ziepe.ca, kees@kernel.org, kys@microsoft.com, leon@kernel.org, liam@infradead.org, lizhi.hou@amd.com, ljs@kernel.org, longli@microsoft.com, 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, wei.liu@kernel.org, dri-devel@lists.freedesktop.org, linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-rdma@vger.kernel.org Subject: Re: [PATCH v8 5/8] drm/nouveau: Use hmm_range_fault_unlocked_timeout() for SVM faults Message-ID: References: <178371866223.900500.12312667138651735591.stgit@skinsburskii> <178371881847.900500.8789369230260725500.stgit@skinsburskii> <20260710151222.ddb35eab9c81a8720491464a@linux-foundation.org> <20260710224833.9caf2a0a9906f0515e326a45@linux-foundation.org> Precedence: bulk X-Mailing-List: linux-hyperv@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260710224833.9caf2a0a9906f0515e326a45@linux-foundation.org> On Fri, Jul 10, 2026 at 10:48:33PM -0700, Andrew Morton wrote: > On Fri, 10 Jul 2026 20:16:35 -0700 Stanislav Kinsburskii wrote: > > > On Fri, Jul 10, 2026 at 03:12:22PM -0700, Andrew Morton wrote: > > > On Fri, 10 Jul 2026 14:26:58 -0700 Stanislav Kinsburskii wrote: > > > > > > > @@ -683,15 +683,11 @@ static int nouveau_range_fault(struct nouveau_svmm *svmm, > > > > goto out; > > > > } > > > > > > > > - range.notifier_seq = mmu_interval_read_begin(range.notifier); > > > > - mmap_read_lock(mm); > > > > - ret = hmm_range_fault(&range); > > > > - mmap_read_unlock(mm); > > > > - if (ret) { > > > > - if (ret == -EBUSY) > > > > - continue; > > > > + ret = hmm_range_fault_unlocked_timeout(&range, > > > > + max(timeout - jiffies, > > > > + 1L)); > > > > > > "1UL" here? I'd have expected min() to warn, as it likes to do. > > > > I'm not sure... The "timeout - jiffies" can become negative. > > Won't 1UL convert both of them to "UL" and thus make the comparison > > overflow? > > `timeout' and `jiffies' are both unsigned long. Yeah, I’m sorry for the sloppy wording. What I meant was: will "max(timeout - jiffies, 1UL)" correctly handle the case where jiffies < timeout? Thanks, Stanislav