| Message ID | 20210422122038.2192933-3-ming.lei@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | block: support bio based io polling | expand |
On 4/22/21 2:20 PM, Ming Lei wrote: > '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 <hch@lst.de> > Signed-off-by: Ming Lei <ming.lei@redhat.com> > --- > 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 ff832e698efb..a0c4f41dfc83 100644 > --- a/include/linux/bvec.h > +++ b/include/linux/bvec.h > @@ -43,7 +43,7 @@ struct bvec_iter { > > unsigned int bi_bvec_done; /* number of bytes completed in > current bvec */ > -}; > +} __packed; > > struct bvec_iter_all { > struct bio_vec bv; > Reviewed-by: Hannes Reinecke <hare@suse.de> Cheers, Hannes
diff --git a/include/linux/bvec.h b/include/linux/bvec.h index ff832e698efb..a0c4f41dfc83 100644 --- a/include/linux/bvec.h +++ b/include/linux/bvec.h @@ -43,7 +43,7 @@ struct bvec_iter { unsigned int bi_bvec_done; /* number of bytes completed in current bvec */ -}; +} __packed; struct bvec_iter_all { struct bio_vec bv;
'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 <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@redhat.com> --- include/linux/bvec.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)