From: Vlastimil Babka <vbabka@xxxxxxx> Subject: mm, slab: make flush_slab() possible to call with irqs enabled Currently flush_slab() is always called with disabled IRQs if it's needed, but the following patches will change that, so add a parameter to control IRQ disabling within the function, which only protects the kmem_cache_cpu manipulation and not the call to deactivate_slab() which doesn't need it. Link: https://lkml.kernel.org/r/20210805152000.12817-29-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: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/slub.c | 24 ++++++++++++++++++------ 1 file changed, 18 insertions(+), 6 deletions(-) --- a/mm/slub.c~mm-slab-make-flush_slab-possible-to-call-with-irqs-enabled +++ a/mm/slub.c @@ -2480,16 +2480,28 @@ static void put_cpu_partial(struct kmem_ #endif /* CONFIG_SLUB_CPU_PARTIAL */ } -static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c) +static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c, + bool lock) { - void *freelist = c->freelist; - struct page *page = c->page; + unsigned long flags; + void *freelist; + struct page *page; + + if (lock) + local_irq_save(flags); + + freelist = c->freelist; + page = c->page; c->page = NULL; c->freelist = NULL; c->tid = next_tid(c->tid); - deactivate_slab(s, page, freelist); + if (lock) + local_irq_restore(flags); + + if (page) + deactivate_slab(s, page, freelist); stat(s, CPUSLAB_FLUSH); } @@ -2499,7 +2511,7 @@ static inline void __flush_cpu_slab(stru struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu); if (c->page) - flush_slab(s, c); + flush_slab(s, c, false); unfreeze_partials_cpu(s, c); } @@ -2515,7 +2527,7 @@ static void flush_cpu_slab(void *d) struct kmem_cache_cpu *c = this_cpu_ptr(s->cpu_slab); if (c->page) - flush_slab(s, c); + flush_slab(s, c, false); unfreeze_partials(s); } _
