svn commit: r364044 - in head: share/man/man9 sys/compat/linuxkpi/common/src sys/kern sys/security/audit sys/sys

[Alan Somers]

On Fri, Aug 7, 2020 at 5:06 PM Mateusz Guzik <mjg at freebsd.org> wrote:

> Author: mjg
> Date: Fri Aug  7 23:06:40 2020
> New Revision: 364044
> URL: https://svnweb.freebsd.org/changeset/base/364044
>
> Log:
>   vfs: add VOP_STAT
>
>   The current scheme of calling VOP_GETATTR adds avoidable overhead.
>
>   An example with tmpfs doing fstat (ops/s):
>   before: 7488958
>   after:  7913833
>
>   Reviewed by:  kib (previous version)
>   Differential Revision:        https://reviews.freebsd.org/D25910
>
> Modified:
>   head/share/man/man9/Makefile
>   head/share/man/man9/VOP_ATTRIB.9
>   head/sys/compat/linuxkpi/common/src/linux_compat.c
>   head/sys/kern/vfs_default.c
>   head/sys/kern/vfs_syscalls.c
>   head/sys/kern/vfs_vnops.c
>   head/sys/kern/vnode_if.src
>   head/sys/security/audit/audit_arg.c
>   head/sys/sys/vnode.h
>

What avoidable overhead? The tmpfs_stat handler that you added in your next
commit looks pretty much the same as vop_getattr.  I'm missing where the
performance improvement comes from.  Could you please fill me in?
-Alan