Re: [PATCH 1/2] mm: add vma_has_locality()

From: Yu Zhao <yuzhao@google.com>
To: Yuanchu Xie <yuanchu@google.com>
Cc: Ivan Babrou <ivan@cloudflare.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Andrew Morton <akpm@linux-foundation.org>,
	Steven Barrett <steven@liquorix.net>,
	Brian Geffon <bgeffon@google.com>,
	Oleksandr Natalenko <oleksandr@natalenko.name>,
	Suren Baghdasaryan <surenb@google.com>,
	Arnd Bergmann <arnd@arndb.de>, Peter Xu <peterx@redhat.com>,
	Hugh Dickins <hughd@google.com>,
	Gaosheng Cui <cuigaosheng1@huawei.com>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org
Subject: Re: [PATCH 1/2] mm: add vma_has_locality()
Date: Thu, 22 Dec 2022 12:52:07 -0700	[thread overview]
Message-ID: <CAOUHufYN8UPHrsni5fohOUK4=Od8Ny312CJrKvHjou=Zxj=+DQ@mail.gmail.com> (raw)
In-Reply-To: <20221222061341.381903-1-yuanchu@google.com>

On Wed, Dec 21, 2022 at 11:13 PM Yuanchu Xie <yuanchu@google.com> wrote:
>
> From: Yu Zhao <yuzhao@google.com>
>
> Currently in vm_flags in vm_area_struct, both VM_SEQ_READ and
> VM_RAND_READ indicate a lack of locality in accesses to the vma. Some
> places that check for locality are missing one of them. We add
> vma_has_locality to replace the existing locality checks for clarity.

Need benchmark results. A simple fio test will do; doesn't need to be
the curl one.

> +       /*
> +        * If we are reclaiming on behalf of a cgroup, skip counting on behalf
> +        * of references from different cgroups

Nit: add a period at the end.

> @@ -906,6 +908,7 @@ int folio_referenced(struct folio *folio, int is_locked,
>                 .arg = (void *)&pra,
>                 .anon_lock = folio_lock_anon_vma_read,
>                 .try_lock = true,
> +               .invalid_vma = invalid_folio_referenced_vma,

Nice. (What I suggested isn't as clean:
https://lore.kernel.org/all/Y31s%2FK8T85jh05wH@google.com/)