Re: [RFC PATCH v2 38/48] lib: Kconfig: add a config symbol for getting lmb memory map updates

[Tom Rini <trini@konsulko.com>]

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On Tue, Jul 23, 2024 at 01:42:59PM +0100, Simon Glass wrote:
> Hi Sughosh,
> 
> On Mon, 22 Jul 2024 at 13:59, Sughosh Ganu <sughosh.ganu@linaro.org> wrote:
> >
> > On Mon, 22 Jul 2024 at 18:00, Ilias Apalodimas
> > <ilias.apalodimas@linaro.org> wrote:
> > >
> > > On Fri, 5 Jul 2024 at 22:51, Tom Rini <trini@konsulko.com> wrote:
> > > >
> > > > On Thu, Jul 04, 2024 at 01:05:34PM +0530, Sughosh Ganu wrote:
> > > >
> > > > > Add a Kconfig symbol to enable getting updates on any memory map
> > > > > changes that might be done by the LMB module. This notification
> > > > > mechanism can then be used to have a synchronous view of allocated and
> > > > > free memory.
> > > > >
> > > > > Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
> > > > > ---
> > > > > Changes since V1:
> > > > > * Change the description to highlight only LMB notifications.
> > > > > * Add a separate line for dependencies.
> > > > >
> > > > >  lib/Kconfig | 10 ++++++++++
> > > > >  1 file changed, 10 insertions(+)
> > > > >
> > > > > diff --git a/lib/Kconfig b/lib/Kconfig
> > > > > index 7eea517b3b..b422183a0f 100644
> > > > > --- a/lib/Kconfig
> > > > > +++ b/lib/Kconfig
> > > > > @@ -74,6 +74,16 @@ config HAVE_PRIVATE_LIBGCC
> > > > >  config LIB_UUID
> > > > >       bool
> > > > >
> > > > > +config MEM_MAP_UPDATE_NOTIFY
> > > > > +     bool "Get notified of any changes to the LMB memory map"
> > > > > +     depends on EVENT && LMB && EFI_LOADER
> > > > > +     default y
> > > > > +     help
> > > > > +       Enable this option to get notification on any changes to the
> > > > > +       memory that is allocated or freed by the LMB module. This will
> > > > > +       allow different modules that allocate memory or maintain a memory
> > > > > +       map to have a synchronous view of available and allocated memory.
> > > >
> > > > This needs to be select'd when it's going to be used, opting out of
> > > > making sure memory reservations are obeyed isn't a good idea.
> > >
> > > +1 which begs the question, do we need the config option at all ?
> >
> > The config symbol can be used for removing the code for platforms
> > which do not support EFI ?
> 
> I am still of the so-far firm opinion that this can be done once,
> before booting, rather than maintaining two separate tables as we go.

Did you see the part in the thread where he explained the multiple entry
points that would need to be kept in sync?

-- 
Tom

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