From: Uladzislau Rezki <urezki@gmail.com>
To: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc: Uladzislau Rezki <urezki@gmail.com>,
Adrian Huang <adrianhuang0701@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Christoph Hellwig <hch@infradead.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Adrian Huang <ahuang12@lenovo.com>
Subject: Re: [PATCH 1/1] mm: vmalloc: Optimize vmap_lazy_nr arithmetic when purging each vmap_area
Date: Mon, 2 Sep 2024 19:03:02 +0200 [thread overview]
Message-ID: <ZtXvxuD-xkUkveRo@pc636> (raw)
In-Reply-To: <ea017b05-7a42-4d3a-a1f2-9bceb56966e3@wanadoo.fr>
Hello!
>
> Hi,
>
> unrelated to your use case, but something that coud easily save a few cycles
> on some system, IMHO.
>
> Maybe:
>
> #if NR_CPUS > 1
> static __read_mostly unsigned int nr_vmap_nodes = 1;
> static __read_mostly unsigned int vmap_zone_size = 1;
> #else
> #define nr_vmap_nodes 1
> #define vmap_zone_size 1
> #endif
>
> So that the compiler can do a better job because some loops can be optimized
> away and there is no need to access some memory to get theses values.
>
> Not sure if such a use case can exist or is of any interest.
>
> This is valide because of [1] and the #ifdef around the num_possible_cpus()
> declaration [2, 3].
>
>
> Just my 2c.
>
Thank you, i see your point.
--
Uladzislau Rezki
next prev parent reply other threads:[~2024-09-02 17:03 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-08-29 13:06 Adrian Huang
2024-08-29 19:00 ` Uladzislau Rezki
2024-08-30 16:26 ` Uladzislau Rezki
2024-08-31 7:03 ` Christophe JAILLET
2024-09-02 17:03 ` Uladzislau Rezki [this message]
2024-09-02 12:00 ` Adrian Huang
2024-09-02 17:00 ` Uladzislau Rezki
2024-08-31 0:33 ` Andrew Morton
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