Messages in this thread | | | Date | Thu, 10 Jun 2021 11:36:36 +0300 | From | Cyrill Gorcunov <> | Subject | Re: [RFC v2 29/34] mm: slub: Move flush_cpu_slab() invocations __free_slab() invocations out of IRQ context |
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On Thu, Jun 10, 2021 at 10:32:14AM +0200, Vlastimil Babka wrote: > >> static void flush_all(struct kmem_cache *s) > >> { > >> - on_each_cpu_cond(has_cpu_slab, flush_cpu_slab, s, 1); > >> + struct slub_flush_work *sfw; > >> + unsigned int cpu; > >> + > >> + cpus_read_lock(); > >> + mutex_lock(&flush_lock); > >> + > > > > Hi, Vlastimil! Could you please point why do you lock cpus first and > > mutex only after? Why not mutex_lock + cpus_read_lock instead? > > Good question! I must admit I didn't think about it much and just followed the > order that was in the original Sebastian's patch [1] > But there was a good reason for this order as some paths via > __kmem_cache_shutdown() and __kmem_cache_shrink() were alreadu called under > cpus_read_lock. Meanwhile mainline (me, actually) removed those, so now it > doesn't seem to be a need to keep this order anymore and we could switch it.
I bet we should switch :) But we can do that on top later, once series is settled down and merged.
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