On Wed, Sep 11, 2019 at 03:55:51AM -0700, Christoph Hellwig wrote:
> ... and there went my hopes to eventually squeeze xfs_ifork into
> a single 64-byte cacheline. But the analys looks sensible.
Not sure what the issue is here:
struct xfs_ifork {
int64_t if_bytes; /* 0 8 */
struct xfs_btree_block * if_broot; /* 8 8 */
unsigned int if_seq; /* 16 4 */
int if_height; /* 20 4 */
union {
void * if_root; /* 24 8 */
char * if_data; /* 24 8 */
} if_u1; /* 24 8 */
short int if_broot_bytes; /* 32 2 */
unsigned char if_flags; /* 34 1 */
/* size: 40, cachelines: 1, members: 7 */
/* padding: 5 */
/* last cacheline: 40 bytes */
};
it's already well inside a 64-byte single cacheline, even with a
64bit if_bytes. Yes, I've just pushed it from 32 to 40 bytes, but
but if that is a problem we could pack some things more tightly...
Cheers,
Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
