From: Jason Gunthorpe <jgg@ziepe.ca>
To: Stanislav Kinsburskii <skinsburskii@gmail.com>
Cc: airlied@gmail.com, akhilesh@ee.iitb.ac.in,
akpm@linux-foundation.org, corbet@lwn.net, dakr@kernel.org,
david@kernel.org, decui@microsoft.com, haiyangz@microsoft.com,
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 v7 2/8] mm/hmm: add hmm_range_fault_unlocked_timeout() for mmap lock-drop support
Date: Fri, 10 Jul 2026 13:27:49 -0300 [thread overview]
Message-ID: <20260710162749.GP118978@ziepe.ca> (raw)
In-Reply-To: <178345362182.660027.12809852179204464964.stgit@skinsburskii>
On Tue, Jul 07, 2026 at 12:47:01PM -0700, Stanislav Kinsburskii wrote:
> +int hmm_range_fault_unlocked_timeout(struct hmm_range *range,
> + unsigned long timeout)
> +{
> + struct mm_struct *mm = range->notifier->mm;
> + unsigned long deadline = 0;
> + int locked, ret;
> +
> + if (timeout)
> + deadline = jiffies + timeout;
> +
> + do {
> + if (fatal_signal_pending(current))
> + return -EINTR;
> +
> + if (timeout && time_after(jiffies, deadline))
> + return -EBUSY;
I really dislike there is a timeout here, HMM is supposed to be more
deterministic. GUP doesn't have a timeout, what is this about?
Jason
WARNING: multiple messages have this Message-ID (diff)
From: Jason Gunthorpe <jgg@ziepe.ca>
To: Stanislav Kinsburskii <skinsburskii@gmail.com>
Cc: akhilesh@ee.iitb.ac.in, akpm@linux-foundation.org,
corbet@lwn.net, dakr@kernel.org, david@kernel.org,
decui@microsoft.com, haiyangz@microsoft.com, kees@kernel.org,
kys@microsoft.com, leon@kernel.org, liam@infradead.org,
lizhi.hou@amd.com, ljs@kernel.org, longli@microsoft.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,
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 v7 2/8] mm/hmm: add hmm_range_fault_unlocked_timeout() for mmap lock-drop support
Date: Fri, 10 Jul 2026 13:27:49 -0300 [thread overview]
Message-ID: <20260710162749.GP118978@ziepe.ca> (raw)
In-Reply-To: <178345362182.660027.12809852179204464964.stgit@skinsburskii>
On Tue, Jul 07, 2026 at 12:47:01PM -0700, Stanislav Kinsburskii wrote:
> +int hmm_range_fault_unlocked_timeout(struct hmm_range *range,
> + unsigned long timeout)
> +{
> + struct mm_struct *mm = range->notifier->mm;
> + unsigned long deadline = 0;
> + int locked, ret;
> +
> + if (timeout)
> + deadline = jiffies + timeout;
> +
> + do {
> + if (fatal_signal_pending(current))
> + return -EINTR;
> +
> + if (timeout && time_after(jiffies, deadline))
> + return -EBUSY;
I really dislike there is a timeout here, HMM is supposed to be more
deterministic. GUP doesn't have a timeout, what is this about?
Jason
next prev parent reply other threads:[~2026-07-10 16:27 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-07 19:46 [PATCH v7 0/8] mm/hmm: Add mmap lock-drop support for userfaultfd-backed mappings Stanislav Kinsburskii
2026-07-07 19:46 ` [PATCH v7 1/8] mm/hmm: move page fault handling out of walk callbacks Stanislav Kinsburskii
2026-07-10 16:31 ` Jason Gunthorpe
2026-07-10 16:31 ` Jason Gunthorpe
2026-07-07 19:47 ` [PATCH v7 2/8] mm/hmm: add hmm_range_fault_unlocked_timeout() for mmap lock-drop support Stanislav Kinsburskii
2026-07-10 16:27 ` Jason Gunthorpe [this message]
2026-07-10 16:27 ` Jason Gunthorpe
2026-07-10 16:47 ` Jason Gunthorpe
2026-07-10 16:47 ` Jason Gunthorpe
2026-07-10 17:02 ` Stanislav Kinsburskii
2026-07-10 17:02 ` Stanislav Kinsburskii
2026-07-10 18:03 ` Jason Gunthorpe
2026-07-10 18:03 ` Jason Gunthorpe
2026-07-10 18:07 ` Stanislav Kinsburskii
2026-07-10 18:07 ` Stanislav Kinsburskii
2026-07-10 16:48 ` Stanislav Kinsburskii
2026-07-10 16:48 ` Stanislav Kinsburskii
2026-07-10 16:38 ` Jason Gunthorpe
2026-07-10 16:38 ` Jason Gunthorpe
2026-07-10 17:06 ` Stanislav Kinsburskii
2026-07-10 17:06 ` Stanislav Kinsburskii
2026-07-07 19:47 ` [PATCH v7 3/8] selftests/mm: add HMM tests for mmap lock-dropping faults Stanislav Kinsburskii
2026-07-07 19:47 ` [PATCH v7 4/8] mshv: Use hmm_range_fault_unlocked_timeout() for region faults Stanislav Kinsburskii
2026-07-10 16:39 ` Jason Gunthorpe
2026-07-10 16:39 ` Jason Gunthorpe
2026-07-07 19:47 ` [PATCH v7 5/8] drm/nouveau: Use hmm_range_fault_unlocked_timeout() for SVM faults Stanislav Kinsburskii
2026-07-10 16:40 ` Jason Gunthorpe
2026-07-10 16:40 ` Jason Gunthorpe
2026-07-07 19:47 ` [PATCH v7 6/8] RDMA/umem: Use hmm_range_fault_unlocked_timeout() for ODP faults Stanislav Kinsburskii
2026-07-10 16:43 ` Jason Gunthorpe
2026-07-10 16:43 ` Jason Gunthorpe
2026-07-07 19:47 ` [PATCH v7 7/8] accel/amdxdna: Use hmm_range_fault_unlocked_timeout() for range population Stanislav Kinsburskii
2026-07-10 16:43 ` Jason Gunthorpe
2026-07-10 16:43 ` Jason Gunthorpe
2026-07-07 19:47 ` [PATCH v7 8/8] drm/gpusvm: Use hmm_range_fault_unlocked_timeout() for range faults Stanislav Kinsburskii
2026-07-10 16:44 ` Jason Gunthorpe
2026-07-10 16:44 ` Jason Gunthorpe
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