Author: mjg Date: Sun Aug 18 18:40:12 2019 New Revision: 351193 URL: https://svnweb.freebsd.org/changeset/base/351193
Log: vfs: stop always overwriting ->mnt_stat in VFS_STATFS The struct is already populated on each mount (and remount). Fields are either constant or not used by filesystem in the first place. Some infrequently used functions use it to avoid having to allocate a new buffer and are left alone. The current code results in an avoidable copying single-threaded and significant cache line bouncing multithreaded While here deduplicate initial filling of the struct. Reviewed by: kib Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D21317 Modified: head/sys/kern/vfs_mount.c head/sys/kern/vfs_syscalls.c Modified: head/sys/kern/vfs_mount.c ============================================================================== --- head/sys/kern/vfs_mount.c Sun Aug 18 17:12:06 2019 (r351192) +++ head/sys/kern/vfs_mount.c Sun Aug 18 18:40:12 2019 (r351193) @@ -1831,12 +1831,15 @@ vfs_copyopt(struct vfsoptlist *opts, const char *name, int __vfs_statfs(struct mount *mp, struct statfs *sbp) { - int error; - error = mp->mnt_op->vfs_statfs(mp, &mp->mnt_stat); - if (sbp != &mp->mnt_stat) - *sbp = mp->mnt_stat; - return (error); + /* + * Set these in case the underlying filesystem fails to do so. + */ + sbp->f_version = STATFS_VERSION; + sbp->f_namemax = NAME_MAX; + sbp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK; + + return (mp->mnt_op->vfs_statfs(mp, sbp)); } void Modified: head/sys/kern/vfs_syscalls.c ============================================================================== --- head/sys/kern/vfs_syscalls.c Sun Aug 18 17:12:06 2019 (r351192) +++ head/sys/kern/vfs_syscalls.c Sun Aug 18 18:40:12 2019 (r351193) @@ -248,7 +248,6 @@ statfs_scale_blocks(struct statfs *sf, long max_size) static int kern_do_statfs(struct thread *td, struct mount *mp, struct statfs *buf) { - struct statfs *sp; int error; if (mp == NULL) @@ -262,17 +261,9 @@ kern_do_statfs(struct thread *td, struct mount *mp, st if (error != 0) goto out; #endif - /* - * Set these in case the underlying filesystem fails to do so. - */ - sp = &mp->mnt_stat; - sp->f_version = STATFS_VERSION; - sp->f_namemax = NAME_MAX; - sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK; - error = VFS_STATFS(mp, sp); + error = VFS_STATFS(mp, buf); if (error != 0) goto out; - *buf = *sp; if (priv_check(td, PRIV_VFS_GENERATION)) { buf->f_fsid.val[0] = buf->f_fsid.val[1] = 0; prison_enforce_statfs(td->td_ucred, mp, buf); @@ -476,13 +467,6 @@ restart: if (sfsp != NULL && count < maxcount) { sp = &mp->mnt_stat; /* - * Set these in case the underlying filesystem - * fails to do so. - */ - sp->f_version = STATFS_VERSION; - sp->f_namemax = NAME_MAX; - sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK; - /* * If MNT_NOWAIT is specified, do not refresh * the fsstat cache. */ @@ -4545,7 +4529,6 @@ sys_fhstatfs(struct thread *td, struct fhstatfs_args * int kern_fhstatfs(struct thread *td, fhandle_t fh, struct statfs *buf) { - struct statfs *sp; struct mount *mp; struct vnode *vp; int error; @@ -4569,16 +4552,7 @@ kern_fhstatfs(struct thread *td, fhandle_t fh, struct if (error != 0) goto out; #endif - /* - * Set these in case the underlying filesystem fails to do so. - */ - sp = &mp->mnt_stat; - sp->f_version = STATFS_VERSION; - sp->f_namemax = NAME_MAX; - sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK; - error = VFS_STATFS(mp, sp); - if (error == 0) - *buf = *sp; + error = VFS_STATFS(mp, buf); out: vfs_unbusy(mp); return (error); _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
