From: Vlastimil Babka <vbabka@xxxxxxx>
Subject: mm, slub: remove redundant unfreeze_partials() from put_cpu_partial()
Commit d6e0b7fa1186 ("slub: make dead caches discard free slabs
immediately") introduced cpu partial flushing for kmemcg caches, based on
setting the target cpu_partial to 0 and adding a flushing check in
put_cpu_partial(). This code that sets cpu_partial to 0 was later moved
by c9fc586403e7 ("slab: introduce __kmemcg_cache_deactivate()") and
ultimately removed by 9855609bde03 ("mm: memcg/slab: use a single set of
kmem_caches for all accounted allocations"). However the check and flush
in put_cpu_partial() was never removed, although it's effectively a dead
code. So this patch removes it.
Note that d6e0b7fa1186 also added preempt_disable()/enable() to
unfreeze_partials() which could be thus also considered unnecessary. But
further patches will rely on it, so keep it.
Link: https://lkml.kernel.org/r/20210904105003.11688-6-vbabka@xxxxxxx
Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: Qian Cai <quic_qiancai@xxxxxxxxxxx>
Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/slub.c | 7 -------
1 file changed, 7 deletions(-)
--- a/mm/slub.c~mm-slub-remove-redundant-unfreeze_partials-from-put_cpu_partial
+++ a/mm/slub.c
@@ -2466,13 +2466,6 @@ static void put_cpu_partial(struct kmem_
} while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page)
!= oldpage);
- if (unlikely(!slub_cpu_partial(s))) {
- unsigned long flags;
-
- local_irq_save(flags);
- unfreeze_partials(s, this_cpu_ptr(s->cpu_slab));
- local_irq_restore(flags);
- }
preempt_enable();
#endif /* CONFIG_SLUB_CPU_PARTIAL */
}
_
