From: Mateusz Guzik <mjguzik@gmail.com>
To: Suren Baghdasaryan <surenb@google.com>
Cc: akpm@linux-foundation.org, peterz@infradead.org,
willy@infradead.org, liam.howlett@oracle.com,
lorenzo.stoakes@oracle.com, david.laight.linux@gmail.com,
mhocko@suse.com, vbabka@suse.cz, hannes@cmpxchg.org,
oliver.sang@intel.com, mgorman@techsingularity.net,
david@redhat.com, peterx@redhat.com, oleg@redhat.com,
dave@stgolabs.net, paulmck@kernel.org, brauner@kernel.org,
dhowells@redhat.com, hdanton@sina.com, hughd@google.com,
lokeshgidra@google.com, minchan@google.com, jannh@google.com,
shakeel.butt@linux.dev, souravpanda@google.com,
pasha.tatashin@soleen.com, klarasmodin@gmail.com,
richard.weiyang@gmail.com, corbet@lwn.net,
linux-doc@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, kernel-team@android.com
Subject: Re: [PATCH v9 11/17] mm: replace vm_lock and detached flag with a reference count
Date: Sat, 11 Jan 2025 21:31:31 +0100 [thread overview]
Message-ID: <CAGudoHH6TKX8EnoK2aSSBc_4EKgOWV=bRAqreFWbEqBJL5RcKQ@mail.gmail.com> (raw)
In-Reply-To: <CAJuCfpGu4UVXiBaivTVOGNBVVz3rhZ+VY27gT3_R0cTij5fTGw@mail.gmail.com>
On Sat, Jan 11, 2025 at 9:14 PM Suren Baghdasaryan <surenb@google.com> wrote:
>
> On Sat, Jan 11, 2025 at 3:24 AM Mateusz Guzik <mjguzik@gmail.com> wrote:
> > The previous modification of this spot to raw_read_seqcount loses the
> > acquire fence, making the above comment not line up with the code.
>
> Is it? From reading the seqcount code
> (https://elixir.bootlin.com/linux/v6.13-rc3/source/include/linux/seqlock.h#L211):
>
> raw_read_seqcount()
> seqprop_sequence()
> __seqprop(s, sequence)
> __seqprop_sequence()
> smp_load_acquire()
>
> smp_load_acquire() still provides the acquire fence. Am I missing something?
>
That's fine indeed.
In a different project there is an equivalent API which skips
barriers, too quick glance suggested this is what's going on here. My
bad, sorry for false alarm on this front. :)
--
Mateusz Guzik <mjguzik gmail.com>
next prev parent reply other threads:[~2025-01-11 20:31 UTC|newest]
Thread overview: 140+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-01-11 4:25 [PATCH v9 00/17] reimplement per-vma lock as a refcount Suren Baghdasaryan
2025-01-11 4:25 ` [PATCH v9 01/17] mm: introduce vma_start_read_locked{_nested} helpers Suren Baghdasaryan
2025-01-11 4:25 ` [PATCH v9 02/17] mm: move per-vma lock into vm_area_struct Suren Baghdasaryan
2025-01-11 4:25 ` [PATCH v9 03/17] mm: mark vma as detached until it's added into vma tree Suren Baghdasaryan
2025-01-11 4:25 ` [PATCH v9 04/17] mm: introduce vma_iter_store_attached() to use with attached vmas Suren Baghdasaryan
2025-01-13 11:58 ` Lorenzo Stoakes
2025-01-13 16:31 ` Suren Baghdasaryan
2025-01-13 16:44 ` Lorenzo Stoakes
2025-01-13 16:47 ` Lorenzo Stoakes
2025-01-13 19:09 ` Suren Baghdasaryan
2025-01-14 11:38 ` Lorenzo Stoakes
2025-01-11 4:25 ` [PATCH v9 05/17] mm: mark vmas detached upon exit Suren Baghdasaryan
2025-01-13 12:05 ` Lorenzo Stoakes
2025-01-13 17:02 ` Suren Baghdasaryan
2025-01-13 17:13 ` Lorenzo Stoakes
2025-01-13 19:11 ` Suren Baghdasaryan
2025-01-13 20:32 ` Vlastimil Babka
2025-01-13 20:42 ` Suren Baghdasaryan
2025-01-14 11:36 ` Lorenzo Stoakes
2025-01-11 4:25 ` [PATCH v9 06/17] types: move struct rcuwait into types.h Suren Baghdasaryan
2025-01-13 14:46 ` Lorenzo Stoakes
2025-01-11 4:25 ` [PATCH v9 07/17] mm: allow vma_start_read_locked/vma_start_read_locked_nested to fail Suren Baghdasaryan
2025-01-13 15:25 ` Lorenzo Stoakes
2025-01-13 17:53 ` Suren Baghdasaryan
2025-01-14 11:48 ` Lorenzo Stoakes
2025-01-11 4:25 ` [PATCH v9 08/17] mm: move mmap_init_lock() out of the header file Suren Baghdasaryan
2025-01-13 15:27 ` Lorenzo Stoakes
2025-01-13 17:53 ` Suren Baghdasaryan
2025-01-11 4:25 ` [PATCH v9 09/17] mm: uninline the main body of vma_start_write() Suren Baghdasaryan
2025-01-13 15:52 ` Lorenzo Stoakes
2025-01-11 4:25 ` [PATCH v9 10/17] refcount: introduce __refcount_{add|inc}_not_zero_limited Suren Baghdasaryan
2025-01-11 6:31 ` Hillf Danton
2025-01-11 9:59 ` Suren Baghdasaryan
2025-01-11 10:00 ` Suren Baghdasaryan
2025-01-11 12:13 ` Hillf Danton
2025-01-11 17:11 ` Suren Baghdasaryan
2025-01-11 23:44 ` Hillf Danton
2025-01-12 0:31 ` Suren Baghdasaryan
2025-01-15 9:39 ` Peter Zijlstra
2025-01-16 10:52 ` Hillf Danton
2025-01-11 12:39 ` David Laight
2025-01-11 17:07 ` Matthew Wilcox
2025-01-11 18:30 ` Paul E. McKenney
2025-01-11 22:19 ` David Laight
2025-01-11 22:50 ` [PATCH v9 10/17] refcount: introduce __refcount_{add|inc}_not_zero_limited - clang 17.0.1 bug David Laight
2025-01-12 11:37 ` David Laight
2025-01-12 17:56 ` Paul E. McKenney
2025-01-11 4:25 ` [PATCH v9 11/17] mm: replace vm_lock and detached flag with a reference count Suren Baghdasaryan
2025-01-11 11:24 ` Mateusz Guzik
2025-01-11 20:14 ` Suren Baghdasaryan
2025-01-11 20:16 ` Suren Baghdasaryan
2025-01-11 20:31 ` Mateusz Guzik [this message]
2025-01-11 20:58 ` Suren Baghdasaryan
2025-01-11 20:38 ` Vlastimil Babka
2025-01-13 1:47 ` Wei Yang
2025-01-13 2:25 ` Wei Yang
2025-01-13 21:14 ` Suren Baghdasaryan
2025-01-13 21:08 ` Suren Baghdasaryan
2025-01-15 10:48 ` Peter Zijlstra
2025-01-15 11:13 ` Peter Zijlstra
2025-01-15 15:00 ` Suren Baghdasaryan
2025-01-15 15:35 ` Peter Zijlstra
2025-01-15 15:38 ` Peter Zijlstra
2025-01-15 16:22 ` Suren Baghdasaryan
2025-01-15 16:00 ` [PATCH] refcount: Strengthen inc_not_zero() Peter Zijlstra
2025-01-16 15:12 ` Suren Baghdasaryan
2025-01-17 15:41 ` Will Deacon
2025-01-27 14:09 ` Will Deacon
2025-01-27 19:21 ` Suren Baghdasaryan
2025-01-28 23:51 ` Suren Baghdasaryan
2025-02-06 2:52 ` [PATCH 1/1] refcount: provide ops for cases when object's memory can be reused Suren Baghdasaryan
2025-02-06 10:41 ` Vlastimil Babka
2025-02-06 3:03 ` [PATCH] refcount: Strengthen inc_not_zero() Suren Baghdasaryan
2025-02-13 23:04 ` Suren Baghdasaryan
2025-01-17 16:13 ` Matthew Wilcox
2025-01-12 2:59 ` [PATCH v9 11/17] mm: replace vm_lock and detached flag with a reference count Wei Yang
2025-01-12 17:35 ` Suren Baghdasaryan
2025-01-13 0:59 ` Wei Yang
2025-01-13 2:37 ` Wei Yang
2025-01-13 21:16 ` Suren Baghdasaryan
2025-01-13 9:36 ` Wei Yang
2025-01-13 21:18 ` Suren Baghdasaryan
2025-01-15 2:58 ` Wei Yang
2025-01-15 3:12 ` Suren Baghdasaryan
2025-01-15 12:05 ` Wei Yang
2025-01-15 15:01 ` Suren Baghdasaryan
2025-01-16 1:37 ` Wei Yang
2025-01-16 1:41 ` Suren Baghdasaryan
2025-01-16 9:10 ` Wei Yang
2025-01-11 4:25 ` [PATCH v9 12/17] mm: move lesser used vma_area_struct members into the last cacheline Suren Baghdasaryan
2025-01-13 16:15 ` Lorenzo Stoakes
2025-01-15 10:50 ` Peter Zijlstra
2025-01-15 16:39 ` Suren Baghdasaryan
2025-02-13 22:59 ` Suren Baghdasaryan
2025-01-11 4:26 ` [PATCH v9 13/17] mm/debug: print vm_refcnt state when dumping the vma Suren Baghdasaryan
2025-01-13 16:21 ` Lorenzo Stoakes
2025-01-13 16:35 ` Liam R. Howlett
2025-01-13 17:57 ` Suren Baghdasaryan
2025-01-14 11:41 ` Lorenzo Stoakes
2025-01-11 4:26 ` [PATCH v9 14/17] mm: remove extra vma_numab_state_init() call Suren Baghdasaryan
2025-01-13 16:28 ` Lorenzo Stoakes
2025-01-13 17:56 ` Suren Baghdasaryan
2025-01-14 11:45 ` Lorenzo Stoakes
2025-01-11 4:26 ` [PATCH v9 15/17] mm: prepare lock_vma_under_rcu() for vma reuse possibility Suren Baghdasaryan
2025-01-11 4:26 ` [PATCH v9 16/17] mm: make vma cache SLAB_TYPESAFE_BY_RCU Suren Baghdasaryan
2025-01-15 2:27 ` Wei Yang
2025-01-15 3:15 ` Suren Baghdasaryan
2025-01-15 3:58 ` Liam R. Howlett
2025-01-15 5:41 ` Suren Baghdasaryan
2025-01-15 3:59 ` Mateusz Guzik
2025-01-15 5:47 ` Suren Baghdasaryan
2025-01-15 5:51 ` Mateusz Guzik
2025-01-15 6:41 ` Suren Baghdasaryan
2025-01-15 7:58 ` Vlastimil Babka
2025-01-15 15:10 ` Suren Baghdasaryan
2025-02-13 22:56 ` Suren Baghdasaryan
2025-01-15 12:17 ` Wei Yang
2025-01-15 21:46 ` Suren Baghdasaryan
2025-01-11 4:26 ` [PATCH v9 17/17] docs/mm: document latest changes to vm_lock Suren Baghdasaryan
2025-01-13 16:33 ` Lorenzo Stoakes
2025-01-13 17:56 ` Suren Baghdasaryan
2025-01-11 4:52 ` [PATCH v9 00/17] reimplement per-vma lock as a refcount Matthew Wilcox
2025-01-11 9:45 ` Suren Baghdasaryan
2025-01-13 12:14 ` Lorenzo Stoakes
2025-01-13 16:58 ` Suren Baghdasaryan
2025-01-13 17:11 ` Lorenzo Stoakes
2025-01-13 19:00 ` Suren Baghdasaryan
2025-01-14 11:35 ` Lorenzo Stoakes
2025-01-14 1:49 ` Andrew Morton
2025-01-14 2:53 ` Suren Baghdasaryan
2025-01-14 4:09 ` Andrew Morton
2025-01-14 9:09 ` Vlastimil Babka
2025-01-14 10:27 ` Hillf Danton
2025-01-14 9:47 ` Lorenzo Stoakes
2025-01-14 14:59 ` Liam R. Howlett
2025-01-14 15:54 ` Suren Baghdasaryan
2025-01-15 11:34 ` Lorenzo Stoakes
2025-01-15 15:14 ` Suren Baghdasaryan
2025-01-28 5:26 ` Shivank Garg
2025-01-28 5:50 ` Suren Baghdasaryan
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