From ecd096506922332fdb36ff1211e03601befe6e18 Mon Sep 17 00:00:00 2001 From: Daniel Jordan Date: Wed, 3 Jun 2020 15:59:55 -0700 Subject: mm: make deferred init's max threads arch-specific Using padata during deferred init has only been tested on x86, so for now limit it to this architecture. If another arch wants this, it can find the max thread limit that's best for it and override deferred_page_init_max_threads(). Signed-off-by: Daniel Jordan Signed-off-by: Andrew Morton Tested-by: Josh Triplett Cc: Alexander Duyck Cc: Alex Williamson Cc: Dan Williams Cc: Dave Hansen Cc: David Hildenbrand Cc: Herbert Xu Cc: Jason Gunthorpe Cc: Jonathan Corbet Cc: Kirill Tkhai Cc: Michal Hocko Cc: Pavel Machek Cc: Pavel Tatashin Cc: Peter Zijlstra Cc: Randy Dunlap Cc: Robert Elliott Cc: Shile Zhang Cc: Steffen Klassert Cc: Steven Sistare Cc: Tejun Heo Cc: Zi Yan Link: http://lkml.kernel.org/r/20200527173608.2885243-8-daniel.m.jordan@oracle.com Signed-off-by: Linus Torvalds --- mm/page_alloc.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) (limited to 'mm') diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 27ec5dc4db33..fb9dec1c1976 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1836,6 +1836,13 @@ deferred_init_memmap_chunk(unsigned long start_pfn, unsigned long end_pfn, } } +/* An arch may override for more concurrency. */ +__weak int __init +deferred_page_init_max_threads(const struct cpumask *node_cpumask) +{ + return 1; +} + /* Initialise remaining memory on a node */ static int __init deferred_init_memmap(void *data) { @@ -1884,11 +1891,7 @@ static int __init deferred_init_memmap(void *data) first_init_pfn)) goto zone_empty; - /* - * More CPUs always led to greater speedups on tested systems, up to - * all the nodes' CPUs. Use all since the system is otherwise idle now. - */ - max_threads = max(cpumask_weight(cpumask), 1u); + max_threads = deferred_page_init_max_threads(cpumask); while (spfn < epfn) { unsigned long epfn_align = ALIGN(epfn, PAGES_PER_SECTION); -- cgit v1.2.3