From: Andrew Morton <akpm@linux-foundation.org>
To: Suren Baghdasaryan <surenb@google.com>
Cc: willy@infradead.org, liam.howlett@oracle.com,
lorenzo.stoakes@oracle.com, mhocko@suse.com, vbabka@suse.cz,
hannes@cmpxchg.org, mjguzik@gmail.com, oliver.sang@intel.com,
mgorman@techsingularity.net, david@redhat.com, peterx@redhat.com,
oleg@redhat.com, paulmck@kernel.org, brauner@kernel.org,
dhowells@redhat.com, hdanton@sina.com, hughd@google.com,
minchan@google.com, jannh@google.com, shakeel.butt@linux.dev,
souravpanda@google.com, pasha.tatashin@soleen.com,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
kernel-team@android.com
Subject: Re: [PATCH 0/4] move per-vma lock into vm_area_struct
Date: Mon, 11 Nov 2024 16:11:02 -0800 [thread overview]
Message-ID: <20241111161102.e047bce4adfbf38002b7a9cf@linux-foundation.org> (raw)
In-Reply-To: <CAJuCfpGw1Nnh3nonDHv-UAeqTB=-3z1+hJk9Opy4X-6mbvdEhw@mail.gmail.com>
On Mon, 11 Nov 2024 15:19:22 -0800 Suren Baghdasaryan <surenb@google.com> wrote:
> On Mon, Nov 11, 2024 at 2:18 PM Davidlohr Bueso <dave@stgolabs.net> wrote:
> >
> > On Mon, 11 Nov 2024, Suren Baghdasaryan wrote:
> >
> > >To minimize memory overhead, vm_lock implementation is changed from
> > >using rw_semaphore (40 bytes) to an atomic (8 bytes) and several
> > >vm_area_struct members are moved into the last cacheline, resulting
> > >in a less fragmented structure:
> >
> > I am not a fan of building a custom lock, replacing a standard one.
>
> Understandable.
If we're going to invent a new lock type, I'm thinking we should do
that - make it a standaline thing, add full lockdep support, etc.
I wonder if we could remove the lock from the vma altogeher and use an
old-fashioned hashed lock. An array of locks indexed by the vma
address. It might work well enough, although sizing the array would be
difficult.
next prev parent reply other threads:[~2024-11-12 0:11 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-11-11 20:55 Suren Baghdasaryan
2024-11-11 20:55 ` [PATCH 1/4] mm: introduce vma_start_read_locked{_nested} helpers Suren Baghdasaryan
2024-11-11 20:55 ` [PATCH 2/4] mm: move per-vma lock into vm_area_struct Suren Baghdasaryan
2024-11-12 9:36 ` kernel test robot
2024-11-12 9:47 ` kernel test robot
2024-11-12 10:18 ` kernel test robot
2024-11-12 15:57 ` Vlastimil Babka
2024-11-12 16:08 ` Suren Baghdasaryan
2024-11-12 16:58 ` Suren Baghdasaryan
2024-11-11 20:55 ` [PATCH 3/4] mm: replace rw_semaphore with atomic_t in vma_lock Suren Baghdasaryan
2024-11-12 0:06 ` Andrew Morton
2024-11-12 0:52 ` Suren Baghdasaryan
2024-11-12 0:35 ` Davidlohr Bueso
2024-11-12 0:59 ` Suren Baghdasaryan
2024-11-12 4:58 ` Matthew Wilcox
2024-11-12 15:18 ` Suren Baghdasaryan
2024-12-10 22:38 ` Peter Zijlstra
2024-12-10 23:37 ` Suren Baghdasaryan
2024-12-11 8:25 ` Peter Zijlstra
2024-12-11 15:20 ` Suren Baghdasaryan
2024-12-12 3:01 ` Suren Baghdasaryan
2024-12-12 9:16 ` Peter Zijlstra
2024-12-12 14:17 ` Suren Baghdasaryan
2024-12-12 14:19 ` Suren Baghdasaryan
2024-12-13 4:48 ` Suren Baghdasaryan
2024-12-13 9:57 ` Peter Zijlstra
2024-12-13 17:45 ` Suren Baghdasaryan
2024-12-13 18:19 ` Matthew Wilcox
2024-12-13 18:35 ` Peter Zijlstra
2024-12-13 18:37 ` Suren Baghdasaryan
2024-12-16 19:32 ` Suren Baghdasaryan
2024-12-13 9:22 ` Peter Zijlstra
2024-12-13 17:41 ` Suren Baghdasaryan
2024-11-11 20:55 ` [PATCH 4/4] mm: move lesser used vma_area_struct members into the last cacheline Suren Baghdasaryan
2024-11-12 10:07 ` Vlastimil Babka
2024-11-12 15:45 ` Suren Baghdasaryan
2024-11-11 21:41 ` [PATCH 0/4] move per-vma lock into vm_area_struct Suren Baghdasaryan
2024-11-12 2:48 ` Liam R. Howlett
2024-11-12 3:27 ` Suren Baghdasaryan
2024-11-11 22:18 ` Davidlohr Bueso
2024-11-11 23:19 ` Suren Baghdasaryan
2024-11-12 0:03 ` Davidlohr Bueso
2024-11-12 0:43 ` Suren Baghdasaryan
2024-11-12 0:11 ` Andrew Morton [this message]
2024-11-12 0:48 ` Suren Baghdasaryan
2024-11-12 2:35 ` Liam R. Howlett
2024-11-12 3:23 ` Suren Baghdasaryan
2024-11-12 9:39 ` Lorenzo Stoakes
2024-11-12 15:38 ` Suren Baghdasaryan
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