From 19416123ab3e1348b3532347af221d8f60838431 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Tue, 12 Oct 2021 13:12:23 +0200 Subject: [PATCH] block: define 'struct bvec_iter' as packed 'struct bvec_iter' is embedded into 'struct bio', define it as packed so that we can get one extra 4bytes for other uses without expanding bio. 'struct bvec_iter' is often allocated on stack, so making it packed doesn't affect performance. Also I have run io_uring on both nvme/null_blk, and not observe performance effect in this way. Suggested-by: Christoph Hellwig Signed-off-by: Ming Lei Reviewed-by: Sagi Grimberg Reviewed-by: Hannes Reinecke Signed-off-by: Christoph Hellwig Tested-by: Mark Wunderlich Link: https://lore.kernel.org/r/20211012111226.760968-14-hch@lst.de Signed-off-by: Jens Axboe --- include/linux/bvec.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/bvec.h b/include/linux/bvec.h index 0e9bdd4..35c25df 100644 --- a/include/linux/bvec.h +++ b/include/linux/bvec.h @@ -44,7 +44,7 @@ struct bvec_iter { unsigned int bi_bvec_done; /* number of bytes completed in current bvec */ -}; +} __packed; struct bvec_iter_all { struct bio_vec bv; -- 2.7.4