Messages in this thread | | | Date | Thu, 8 Dec 2011 12:56:22 +0530 | Subject | Re: [PATCH 1/1] vmalloc: purge_fragmented_blocks: Acquire spinlock before reading vmap_block | From | Kautuk Consul <> |
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> > That's intentional as an optimization, we don't care if > vb->free + vb->dirty == VMAP_BBMAP_BITS && vb->dirty != VMAP_BBMAP_BITS > would speculatively be true after we grab vb->lock, we'll have to purge it > next time instead. We certainly don't want to grab vb->lock for blocks > that aren't candidates, so this optimization is a singificant speedup.
Ah, I agree. Anyway, the probability of there being too many vmap_blocks being missed due to concurrent changes is not quite high, so I guess its okay that a few vmap_blocks get purged next time.
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