svn commit: r364637 - head/sys/kern

[Jessica Clarke]

On 6 Sep 2020, at 21:46, Alan Somers <asomers at freebsd.org> wrote:
> 
> On Mon, Aug 24, 2020 at 3:01 AM Mateusz Guzik <mjg at freebsd.org> wrote:
> Author: mjg
> Date: Mon Aug 24 09:00:57 2020
> New Revision: 364637
> URL: https://svnweb.freebsd.org/changeset/base/364637
> 
> Log:
>   cache: lockless reverse lookup
> 
>   This enables fully scalable operation for getcwd and significantly improves
>   realpath.
> 
>   For example:
>   PATH_CUSTOM=/usr/src ./getcwd_processes -t 104
>   before:  1550851
>   after: 380135380
> 
>   Tested by:    pho
> 
> Modified:
>   head/sys/kern/vfs_cache.c
> 
> Modified: head/sys/kern/vfs_cache.c
> ==============================================================================
> --- head/sys/kern/vfs_cache.c   Mon Aug 24 09:00:07 2020        (r364636)
> +++ head/sys/kern/vfs_cache.c   Mon Aug 24 09:00:57 2020        (r364637)
> @@ -477,6 +485,8 @@ STATNODE_COUNTER(shrinking_skipped,
>  static void cache_zap_locked(struct namecache *ncp);
>  static int vn_fullpath_hardlink(struct nameidata *ndp, char **retbuf,
>      char **freebuf, size_t *buflen);
> +static int vn_fullpath_any_smr(struct vnode *vp, struct vnode *rdir, char *buf,
> +    char **retbuf, size_t *buflen, bool slash_prefixed, size_t addend);
>  static int vn_fullpath_any(struct vnode *vp, struct vnode *rdir, char *buf,
>      char **retbuf, size_t *buflen);
>  static int vn_fullpath_dir(struct vnode *vp, struct vnode *rdir, char *buf,
> @@ -2476,9 +2486,17 @@ vn_getcwd(char *buf, char **retbuf, size_t *buflen)
> 
> What does the "smr" stand for?

Safe Memory Reclamation (see sys/sys/smr.h and sys/kern/subr_smr.c).

Jess