On Thu, Jun 13, 2019 at 07:59:32PM -0700, Florian Fainelli wrote: > Make ARM64_MODULE_PLTS a selectable Kconfig symbol, since some people > might have very big modules spilling out of the dedicated module area > into vmalloc. Help text is copied from the ARM 32-bit counterpart. > > Signed-off-by: Florian Fainelli <f.faine...@gmail.com> > --- > arch/arm64/Kconfig | 14 +++++++++++++- > 1 file changed, 13 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 697ea0510729..36befe987b73 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -1418,8 +1418,20 @@ config ARM64_SVE > KVM in the same kernel image. > > config ARM64_MODULE_PLTS > - bool > + bool "Use PLTs to allow module memory to spill over into vmalloc area" > select HAVE_MOD_ARCH_SPECIFIC > + help > + Allocate PLTs when loading modules so that jumps and calls whose > + targets are too far away for their relative offsets to be encoded > + in the instructions themselves can be bounced via veneers in the > + module's PLT. This allows modules to be allocated in the generic > + vmalloc area after the dedicated module memory area has been > + exhausted. The modules will use slightly more memory, but after > + rounding up to page size, the actual memory footprint is usually > + the same.
Isn't the worry really about the runtime performance overhead introduced by the veneers, as opposed to the memory usage of the module? > + Disabling this is usually safe for small single-platform > + configurations. If unsure, say y. So should this be on by default? Will
