On Mon, Feb 04, 2019 at 10:20:35PM +0100, Rasmus Villemoes wrote:
> linux/tracepoints.h allows individual subsystems to disable their
> tracepoints. Add such a knob for xfs. Disabling XFS_TRACEPOINTS
> reduces the resident size of xfs.ko by about a third, or ~350 KiB.
LOL. :)
> $ size /tmp/xfs/{a,b}/xfs.ko
> text data bss dec hex filename
> 671726 4129 632 676487 a5287 /tmp/xfs/a/xfs.ko
> 893192 166737 632 1060561 102ed1 /tmp/xfs/b/xfs.ko
>
> Signed-off-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
> ---
> fs/xfs/Kconfig | 9 +++++++++
> fs/xfs/xfs_trace.h | 4 ++++
I think a similar thing ought to apply to fs/xfs/scrub/trace.h, right?
More general questions:
(a) Do we want to be doing this on a per-subsystem basis?
(b) Since xfs_scrub is a separate trace domain, do we want a separate
Kconfig item for toggling scrub trace, or is one big one enough?
(I can't think of why I'd want one on and the other off.)
--D
> 2 files changed, 13 insertions(+)
>
> diff --git a/fs/xfs/Kconfig b/fs/xfs/Kconfig
> index 457ac9f97377..d099e6d9f6c5 100644
> --- a/fs/xfs/Kconfig
> +++ b/fs/xfs/Kconfig
> @@ -141,3 +141,12 @@ config XFS_ASSERT_FATAL
> result in warnings.
>
> This behavior can be modified at runtime via sysfs.
> +
> +config XFS_TRACEPOINTS
> + bool "XFS tracepoints"
> + default y
> + depends on XFS_FS && TRACEPOINTS
> + help
> + Say Y here to build XFS with tracepoints.
> +
> + You can say N here to reduce the size of the kernel image.
> diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
> index 6fcc893dfc91..5fb3d5c0483e 100644
> --- a/fs/xfs/xfs_trace.h
> +++ b/fs/xfs/xfs_trace.h
> @@ -6,6 +6,10 @@
> #undef TRACE_SYSTEM
> #define TRACE_SYSTEM xfs
>
> +#ifndef CONFIG_XFS_TRACEPOINTS
> +#define NOTRACE
> +#endif
> +
> #if !defined(_TRACE_XFS_H) || defined(TRACE_HEADER_MULTI_READ)
> #define _TRACE_XFS_H
>
> --
> 2.20.1
>
