From: David Rientjes <rientjes@google.com>
To: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@suse.cz>,
Roman Gushchin <roman.gushchin@linux.dev>,
Hyeonggon Yoo <42.hyeyoo@gmail.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: slub: make slab_sysfs_init() a late_initcall
Date: Sun, 9 Oct 2022 20:55:44 -0700 (PDT) [thread overview]
Message-ID: <4e36bc37-07c7-b502-572c-62b3aaa2b3cc@google.com> (raw)
In-Reply-To: <20220930102712.789755-1-linux@rasmusvillemoes.dk>
On Fri, 30 Sep 2022, Rasmus Villemoes wrote:
> Currently, slab_sysfs_init() is an __initcall aka device_initcall. It
> is rather time-consuming; on my board it takes around 11ms. That's
> about 1% of the time budget I have from U-Boot letting go and until
> linux must assume responsibility of keeping the external watchdog
> happy.
>
> There's no particular reason this would need to run at device_initcall
> time, so instead make it a late_initcall to allow vital functionality
> to get started a bit sooner.
>
> This actually ends up winning more than just those 11ms, because the
> slab caches that get created during other device_initcalls (and before
> my watchdog device gets probed) now don't end up doing the somewhat
> expensive sysfs_slab_add() themselves. Some example lines (with
> initcall_debug set) before/after:
>
> initcall ext4_init_fs+0x0/0x1ac returned 0 after 1386 usecs
> initcall journal_init+0x0/0x138 returned 0 after 517 usecs
> initcall init_fat_fs+0x0/0x68 returned 0 after 294 usecs
>
> initcall ext4_init_fs+0x0/0x1ac returned 0 after 240 usecs
> initcall journal_init+0x0/0x138 returned 0 after 32 usecs
> initcall init_fat_fs+0x0/0x68 returned 0 after 18 usecs
>
> Altogether, this means I now get to petting the watchdog around 17ms
> sooner. [Of course, the time the other initcalls save is instead spent
> in slab_sysfs_init(), which goes from 11ms to 16ms, so there's no
> overall change in boot time.]
>
> Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: David Rientjes <rientjes@google.com>
next prev parent reply other threads:[~2022-10-10 3:55 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-30 10:27 Rasmus Villemoes
2022-10-03 8:17 ` Hyeonggon Yoo
2022-10-03 10:25 ` Rasmus Villemoes
2022-10-06 6:06 ` Hyeonggon Yoo
2022-10-10 3:55 ` David Rientjes [this message]
2022-10-14 8:26 ` Vlastimil Babka
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