[PATCH] lmb: Default to not-LMB_USE_MAX_REGIONS

[Tom Rini]

On Wed, Feb 08, 2023 at 03:13:31PM +0000, Philippe Schenker wrote:
> On Wed, 2023-02-08 at 09:54 -0500, Tom Rini wrote:
> > On Wed, Feb 08, 2023 at 02:33:58PM +0000, Philippe Schenker wrote:
> > 
> > > Hi Tom,
> > > 
> > > We currently face an issue on our apalis-imx8 machine, that is not
> > > able
> > > to boot with a ramdisk. What happens is that there are all 8 of 8
> > > LMBs
> > > reserved and fdt tries to allocate one more, probably for
> > > relocation.
> > > 
> > > I now stumbled on this recent patch and noticed that in my
> > > understanding
> > > this is introducing a regression to all the boards you remove
> > > `CONFIG_LMB_MAX_REGIONS=64` isn't it? Or do I miss something?
> > > 
> > > For the other question this raises to me is it in general safe to
> > > just
> > > increase this limit, let's say to 16?
> > > 
> > > And since it was quite an effort debugging this issue I thought of
> > > adding a debug print if the MAX cnt in lmb.c is being hit to ease
> > > that
> > > pain for other devs, would you be fine with something like this?
> > 
> > Right, so with the late in the cycle change to make EFI use LMBs as
> > well, a lot of platforms hit the 8 of 8 LMBs now in use problem. The
> > change here switches from a static allocation of a maximum number of
> > LMBs to dynamically allocating as many of them as needed.
> 
> 
> But since you no longer enable LMB_USE_MAX_REGIONS then theres the two
> limits (default=8)
> 
> LMB_MEMORY_REGIONS=8
> LMB_RESERVED_REGIONS=8
> 
> that are limiting the maximum LMB numbers. So in my view this commit
> does create a regression for all boards you delete
> `CONFIG_LMB_MAX_REGIONS=64`.
> 
> At least for me rgn->max is still set to 8 and also after this commit I
> hit that limit. [1]
> 
> [1] https://source.denx.de/u-boot/u-boot/-/blob/master/lib/lmb.c#L288

Ugh, you're right and I missed what this ended up doing, thanks for
explaining it. I'll go revert my commit shortly and pick up one of the
ones that raised the default.

-- 
Tom
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