diff options
| author | Huang Ying <ying.huang@intel.com> | 2024-01-26 16:19:44 +0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-02-22 10:24:41 -0800 |
| commit | 5cec4eb7fad6fb1e9a3dd8403b558d1eff7490ff (patch) | |
| tree | 4c0221b586d5d937922a89ee0cb7c1c4b076192d /mm | |
| parent | 96200c915040c2ec6f6c173a29caf9f7c9c15a7e (diff) | |
| download | linux-5cec4eb7fad6fb1e9a3dd8403b558d1eff7490ff.tar.gz | |
mm and cache_info: remove unnecessary CPU cache info update
For each CPU hotplug event, we will update per-CPU data slice size and
corresponding PCP configuration for every online CPU to make the
implementation simple. But, Kyle reported that this takes tens seconds
during boot on a machine with 34 zones and 3840 CPUs.
So, in this patch, for each CPU hotplug event, we only update per-CPU data
slice size and corresponding PCP configuration for the CPUs that share
caches with the hotplugged CPU. With the patch, the system boot time
reduces 67 seconds on the machine.
Link: https://lkml.kernel.org/r/20240126081944.414520-1-ying.huang@intel.com
Fixes: 362d37a106dd ("mm, pcp: reduce lock contention for draining high-order pages")
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Originally-by: Kyle Meyer <kyle.meyer@hpe.com>
Reported-and-tested-by: Kyle Meyer <kyle.meyer@hpe.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/page_alloc.c | 39 |
1 files changed, 18 insertions, 21 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 150d4f23b0104..9faca05d124e6 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5572,37 +5572,34 @@ static void zone_pcp_update(struct zone *zone, int cpu_online) mutex_unlock(&pcp_batch_high_lock); } -static void zone_pcp_update_cacheinfo(struct zone *zone) +static void zone_pcp_update_cacheinfo(struct zone *zone, unsigned int cpu) { - int cpu; struct per_cpu_pages *pcp; struct cpu_cacheinfo *cci; - for_each_online_cpu(cpu) { - pcp = per_cpu_ptr(zone->per_cpu_pageset, cpu); - cci = get_cpu_cacheinfo(cpu); - /* - * If data cache slice of CPU is large enough, "pcp->batch" - * pages can be preserved in PCP before draining PCP for - * consecutive high-order pages freeing without allocation. - * This can reduce zone lock contention without hurting - * cache-hot pages sharing. - */ - spin_lock(&pcp->lock); - if ((cci->per_cpu_data_slice_size >> PAGE_SHIFT) > 3 * pcp->batch) - pcp->flags |= PCPF_FREE_HIGH_BATCH; - else - pcp->flags &= ~PCPF_FREE_HIGH_BATCH; - spin_unlock(&pcp->lock); - } + pcp = per_cpu_ptr(zone->per_cpu_pageset, cpu); + cci = get_cpu_cacheinfo(cpu); + /* + * If data cache slice of CPU is large enough, "pcp->batch" + * pages can be preserved in PCP before draining PCP for + * consecutive high-order pages freeing without allocation. + * This can reduce zone lock contention without hurting + * cache-hot pages sharing. + */ + spin_lock(&pcp->lock); + if ((cci->per_cpu_data_slice_size >> PAGE_SHIFT) > 3 * pcp->batch) + pcp->flags |= PCPF_FREE_HIGH_BATCH; + else + pcp->flags &= ~PCPF_FREE_HIGH_BATCH; + spin_unlock(&pcp->lock); } -void setup_pcp_cacheinfo(void) +void setup_pcp_cacheinfo(unsigned int cpu) { struct zone *zone; for_each_populated_zone(zone) - zone_pcp_update_cacheinfo(zone); + zone_pcp_update_cacheinfo(zone, cpu); } /* |