From 1a5ad30b89b4e9fa64f75b941a324396738b7616 Mon Sep 17 00:00:00 2001 From: Rasmus Villemoes <linux@rasmusvillemoes.dk> Date: Fri, 30 Sep 2022 12:27:12 +0200 Subject: mm: slub: make slab_sysfs_init() a late_initcall 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: Hyeonggon Yoo <42.hyeyoo@gmail.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> --- mm/slub.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'mm/slub.c') diff --git a/mm/slub.c b/mm/slub.c index 76f4d3c41511..f162683f3006 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -6049,8 +6049,7 @@ static int __init slab_sysfs_init(void) mutex_unlock(&slab_mutex); return 0; } - -__initcall(slab_sysfs_init); +late_initcall(slab_sysfs_init); #endif /* CONFIG_SYSFS */ #if defined(CONFIG_SLUB_DEBUG) && defined(CONFIG_DEBUG_FS) -- cgit v1.2.3