From: Shakeel Butt <shakeel.butt@linux.dev>
To: Suren Baghdasaryan <surenb@google.com>
Cc: akpm@linux-foundation.org, 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, dave@stgolabs.net,
paulmck@kernel.org, brauner@kernel.org, dhowells@redhat.com,
hdanton@sina.com, hughd@google.com, minchan@google.com,
jannh@google.com, souravpanda@google.com,
pasha.tatashin@soleen.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 v4 0/5] move per-vma lock into vm_area_struct
Date: Wed, 20 Nov 2024 14:10:44 -0800 [thread overview]
Message-ID: <hdvig2tptf3hi6nmszafarzqb6j56abfbebppqmruvpihlf435@46b57hyw2pfc> (raw)
In-Reply-To: <20241120000826.335387-1-surenb@google.com>
On Tue, Nov 19, 2024 at 04:08:21PM -0800, Suren Baghdasaryan wrote:
> Back when per-vma locks were introduces, vm_lock was moved out of
> vm_area_struct in [1] because of the performance regression caused by
> false cacheline sharing. Recent investigation [2] revealed that the
> regressions is limited to a rather old Broadwell microarchitecture and
> even there it can be mitigated by disabling adjacent cacheline
> prefetching, see [3].
If 'struct vm_area_struct' is prone to performance issues due to
cacheline misalignments then we should do something about the
__randomize_layout tag for it. I imagine we can identify the fields
which might be performance critical to be on same cacheline or different
cacheline due to false sharing then we can divide the fields into
different cacheline groups and fields can be __randomize_layout within
the group. WDYT?
next prev parent reply other threads:[~2024-11-20 22:10 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-11-20 0:08 Suren Baghdasaryan
2024-11-20 0:08 ` [PATCH v4 1/5] mm: introduce vma_start_read_locked{_nested} helpers Suren Baghdasaryan
2024-11-20 22:11 ` Shakeel Butt
2024-11-20 0:08 ` [PATCH v4 2/5] mm: move per-vma lock into vm_area_struct Suren Baghdasaryan
2024-11-20 23:32 ` Shakeel Butt
2024-11-20 23:44 ` Suren Baghdasaryan
2024-11-21 0:04 ` Shakeel Butt
2024-11-21 0:33 ` Suren Baghdasaryan
2024-11-21 7:01 ` Shakeel Butt
2024-11-21 17:05 ` Suren Baghdasaryan
2024-11-21 18:25 ` Shakeel Butt
2024-11-20 0:08 ` [PATCH v4 3/5] mm: mark vma as detached until it's added into vma tree Suren Baghdasaryan
2024-11-21 0:13 ` Shakeel Butt
2024-11-22 16:46 ` Lorenzo Stoakes
2024-11-22 17:47 ` Suren Baghdasaryan
2024-11-20 0:08 ` [PATCH v4 4/5] mm: make vma cache SLAB_TYPESAFE_BY_RCU Suren Baghdasaryan
2024-11-20 4:36 ` Matthew Wilcox
2024-11-20 6:37 ` Suren Baghdasaryan
2024-11-22 22:43 ` Suren Baghdasaryan
2024-11-20 10:16 ` Vlastimil Babka
2024-11-20 15:54 ` Suren Baghdasaryan
2024-11-20 0:08 ` [PATCH v4 5/5] docs/mm: document latest changes to vm_lock Suren Baghdasaryan
2024-11-20 22:10 ` Shakeel Butt [this message]
2024-11-20 23:52 ` [PATCH v4 0/5] move per-vma lock into vm_area_struct Suren Baghdasaryan
2024-11-21 2:00 ` Matthew Wilcox
2024-11-22 11:56 ` Lorenzo Stoakes
2024-11-22 15:06 ` Suren Baghdasaryan
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