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Date: Fri, 6 Dec 2024 20:29:04 -0800
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, dave@stgolabs.net, 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, corbet@lwn.net,
 linux-doc@vger.kernel.org, linux-mm@kvack.org,
 linux-kernel@vger.kernel.org, kernel-team@android.com, Peter Zijlstra
 <peterz@infradead.org>
Subject: Re: [PATCH v5 0/6] move per-vma lock into vm_area_struct
Message-Id: <20241206202904.e685764837504d97cbc3cf62@linux-foundation.org>
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On Fri,  6 Dec 2024 14:51:57 -0800 Suren Baghdasaryan <surenb@google.com> 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].
> 
> ...
>
> Patch applies over linux-next (due to vm_lock change [5] not in mm tree).
> 
> ...
>
> [5] https://lore.kernel.org/all/20241122174416.1367052-2-surenb@google.com/

Well that's awkward.  I added the "seqlock: add raw_seqcount_try_begin"
series to mm.git.  Peter, please drop your copy from linux-next?