The branch main has been updated by mjg: URL: https://cgit.FreeBSD.org/src/commit/?id=2443068d486020ed9a4250e0d3b28168c40f741a
commit 2443068d486020ed9a4250e0d3b28168c40f741a Author: Mateusz Guzik <[email protected]> AuthorDate: 2021-02-21 19:48:49 +0000 Commit: Mateusz Guzik <[email protected]> CommitDate: 2021-02-21 21:07:14 +0000 vfs: shrink struct vnode to 448 bytes on LP64 ... by moving v_hash into a 4 byte hole. Combined with several previous size reductions this makes the size small enough to fit 9 vnodes per page as opposed to 8. Add a compilation time assert so that this is not unknowingly worsened. Note the structure still remains bigger than it should be. --- sys/sys/vnode.h | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/sys/sys/vnode.h b/sys/sys/vnode.h index d71f3bfcb817..0e46bea14b64 100644 --- a/sys/sys/vnode.h +++ b/sys/sys/vnode.h @@ -109,6 +109,7 @@ struct vnode { short v_irflag; /* i frequently read flags */ seqc_t v_seqc; /* i modification count */ uint32_t v_nchash; /* u namecache hash */ + u_int v_hash; struct vop_vector *v_op; /* u vnode operations vector */ void *v_data; /* u private data for fs */ @@ -172,9 +173,19 @@ struct vnode { int v_writecount; /* I ref count of writers or (negative) text users */ int v_seqc_users; /* i modifications pending */ - u_int v_hash; }; +#ifndef DEBUG_LOCKS +#ifdef _LP64 +/* + * Not crossing 448 bytes fits 9 vnodes per page. If you have to add fields + * to the structure and there is nothing which can be done to prevent growth + * then so be it. But don't grow it without a good reason. + */ +_Static_assert(sizeof(struct vnode) <= 448, "vnode size crosses 448 bytes"); +#endif +#endif + #endif /* defined(_KERNEL) || defined(_KVM_VNODE) */ #define bo2vnode(bo) __containerof((bo), struct vnode, v_bufobj) _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/dev-commits-src-all To unsubscribe, send any mail to "[email protected]"
