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mm/swap: pull the CPU conditional out of __lru_add_drain_all() 

The function is too long, so pull this complicated conditional out into
cpu_needs_drain().  This ends up shrinking the text by 14 bytes,
by allowing GCC to cache the result of calling per_cpu() instead of
relocating each lookup individually.

Link: https://lkml.kernel.org/r/20220617175020.717127-11-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Matthew Wilcox (Oracle) 2022-06-17 18:50:08 +01:00 committed by akpm
parent 82ac64d86f
commit 4864545a46
1 changed files with 16 additions and 8 deletions
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24
mm/swap.c
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@ -765,6 +765,21 @@ static void lru_add_drain_per_cpu(struct work_struct *dummy)
lru_add_and_bh_lrus_drain();
}
static bool cpu_needs_drain(unsigned int cpu)
{
struct cpu_fbatches *fbatches = &per_cpu(cpu_fbatches, cpu);
/* Check these in order of likelihood that they're not zero */
return folio_batch_count(&fbatches->lru_add) ||
data_race(folio_batch_count(&per_cpu(lru_rotate.fbatch, cpu))) ||
folio_batch_count(&fbatches->lru_deactivate_file) ||
folio_batch_count(&fbatches->lru_deactivate) ||
folio_batch_count(&fbatches->lru_lazyfree) ||
folio_batch_count(&fbatches->activate) ||
need_mlock_page_drain(cpu) ||
has_bh_in_lru(cpu, NULL);
}
/*
* Doesn't need any cpu hotplug locking because we do rely on per-cpu
* kworkers being shut down before our page_alloc_cpu_dead callback is
@ -849,14 +864,7 @@ static inline void __lru_add_drain_all(bool force_all_cpus)
for_each_online_cpu(cpu) {
struct work_struct *work = &per_cpu(lru_add_drain_work, cpu);
if (folio_batch_count(&per_cpu(cpu_fbatches.lru_add, cpu)) ||
data_race(folio_batch_count(&per_cpu(lru_rotate.fbatch, cpu))) ||
folio_batch_count(&per_cpu(cpu_fbatches.lru_deactivate_file, cpu)) ||
folio_batch_count(&per_cpu(cpu_fbatches.lru_deactivate, cpu)) ||
folio_batch_count(&per_cpu(cpu_fbatches.lru_lazyfree, cpu)) ||
folio_batch_count(&per_cpu(cpu_fbatches.activate, cpu)) ||
need_mlock_page_drain(cpu) ||
has_bh_in_lru(cpu, NULL)) {
if (cpu_needs_drain(cpu)) {
INIT_WORK(work, lru_add_drain_per_cpu);
queue_work_on(cpu, mm_percpu_wq, work);
__cpumask_set_cpu(cpu, &has_work);