Messages in this thread | | | Date | Thu, 23 Feb 2023 01:03:49 +0000 | From | Hyeonggon Yoo <> | Subject | Re: [PATCH] mm/slub: fix help comment of SLUB_DEBUG[_ON] |
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On Thu, Feb 23, 2023 at 07:20:58AM +0800, Vernon Yang wrote: > Since commit 081248de0a02 ("kset: move /sys/slab to /sys/kernel/slab"), > the SYSFS path of slab was modified, so fix up the help comment of > SLUB_DEBUG to use the correct one. > > And now the "slub_debug" parameter on boot that is support for more > fine grained debug control, so fix up help comment of SLUB_DEBUG_ON > for "no support" to "support". > > Signed-off-by: Vernon Yang <vernon2gm@gmail.com> > --- > mm/Kconfig.debug | 12 ++++++------ > 1 file changed, 6 insertions(+), 6 deletions(-) > > diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug > index fca699ad1fb0..732043bf56c6 100644 > --- a/mm/Kconfig.debug > +++ b/mm/Kconfig.debug > @@ -61,8 +61,8 @@ config SLUB_DEBUG > help > SLUB has extensive debug support features. Disabling these can > result in significant savings in code size. This also disables > - SLUB sysfs support. /sys/slab will not exist and there will be > - no support for cache validation etc. > + SLUB sysfs support. /sys/kernel/slab will not exist and there > + will be no support for cache validation etc.
After commit ab4d5ed5eeda ("slub: Enable sysfs support for !CONFIG_SLUB_DEBUG"), "Disabling SLUB_DEBUG also disables SLUB sysfs support" is not true anymore.
> config SLUB_DEBUG_ON > bool "SLUB debugging on by default" > @@ -73,10 +73,10 @@ config SLUB_DEBUG_ON > Boot with debugging on by default. SLUB boots by default with > the runtime debug capabilities switched off. Enabling this is > equivalent to specifying the "slub_debug" parameter on boot. > - There is no support for more fine grained debug control like > - possible with slub_debug=xxx. SLUB debugging may be switched > - off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying > - "slub_debug=-". > + There is support for more fine grained debug control like > + possible with slub_debug=xxx, details in Documentation/mm/slub.rst. > + SLUB debugging may be switched off in a kernel built with > + CONFIG_SLUB_DEBUG_ON by specifying "slub_debug=-".
I think this is a misunderstanding. SLUB_DEBUG_ON is equivalent to passing boot parameter slub_debug=FUPZ, and what the help text says is that
"You can enable slub debugging by default using this config option but there is no support for fine-grained control like what slub_debug boot parameter provides."
IOW SLUB_DEBUG_ON cannot be used to have same effect as passing something like slub_debug=F.
> > config PAGE_OWNER > bool "Track page owner" > -- > 2.34.1 > >
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