[PATCH 3/4] block: re-organize fields of 'struct hd_part'

Ming Lei
2020-05-07T08:53:13Z

Put all fields accessed in IO path together at the beginning
of the struct, so that all can be fetched in single cacheline.

Cc: Yufen Yu <yuyufen@huawei.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Hou Tao <houtao1@huawei.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
include/linux/genhd.h | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 2732120751e8..e0fab519ce37 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -71,6 +71,14 @@ struct hd_struct {
#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
seqcount_t nr_sects_seq;
#endif
+ unsigned long stamp;
+#ifdef CONFIG_SMP
+ struct disk_stats __percpu *dkstats;
+#else
+ struct disk_stats dkstats;
+#endif
+ struct percpu_ref ref;
+
sector_t alignment_offset;
unsigned int discard_alignment;
struct device __dev;
@@ -80,13 +88,6 @@ struct hd_struct {
#ifdef CONFIG_FAIL_MAKE_REQUEST
int make_it_fail;
#endif
- unsigned long stamp;
-#ifdef CONFIG_SMP
- struct disk_stats __percpu *dkstats;
-#else
- struct disk_stats dkstats;
-#endif
- struct percpu_ref ref;
struct gendisk *disk;
struct rcu_work rcu_work;
};
--
2.25.2