Re: [PATCH] MIPS: fix memory reservation for non-usermem setups

From: Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>
To: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Mike Rapoport <rppt@kernel.org>,
	Tiezhu Yang <yangtiezhu@loongson.cn>,
	Jinyang He <hejinyang@loongson.cn>,
	Youling Tang <tangyouling@loongson.cn>,
	Tobias Wolf <dev-NTEO@vplace.de>,
	Marcin Nowakowski <marcin.nowakowski@mips.com>,
	linux-mips@vger.kernel.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	stable <stable@vger.kernel.org>
Subject: Re: [PATCH] MIPS: fix memory reservation for non-usermem setups
Date: Mon, 12 Apr 2021 23:52:07 -0700	[thread overview]
Message-ID: <CALCv0x2w41HLRLMXSQcnD624kczRGmuR49KSRSDLm5mqmez6cA@mail.gmail.com> (raw)
In-Reply-To: <CALCv0x3rZXK2KYM+twkd_3v2bzqrVAXaA2NnaP8AJh76NeME8w@mail.gmail.com>

On Mon, Apr 12, 2021 at 11:45 PM Ilya Lipnitskiy
<ilya.lipnitskiy@gmail.com> wrote:
>
> Hi Thomas,
>
> On Tue, Apr 6, 2021 at 6:18 AM Thomas Bogendoerfer
> <tsbogend@alpha.franken.de> wrote:
> >
> > On Sat, Apr 03, 2021 at 07:02:13PM -0700, Ilya Lipnitskiy wrote:
> > > Hi Mike,
> > >
> > > On Tue, Mar 16, 2021 at 11:33 PM Mike Rapoport <rppt@kernel.org> wrote:
> > > >
> > > > Hi Ilya,
> > > >
> > > > On Tue, Mar 16, 2021 at 10:10:09PM -0700, Ilya Lipnitskiy wrote:
> > > > > Hi Thomas,
> > > > >
> > > > > On Fri, Mar 12, 2021 at 7:19 AM Thomas Bogendoerfer
> > > > > <tsbogend@alpha.franken.de> wrote:
> > > > > >
> > > > > > On Sun, Mar 07, 2021 at 11:40:30AM -0800, Ilya Lipnitskiy wrote:
> > > > > > > From: Tobias Wolf <dev-NTEO@vplace.de>
> > > > > > >
> > > > > > > Commit 67a3ba25aa95 ("MIPS: Fix incorrect mem=X@Y handling") introduced a new
> > > > > > > issue for rt288x where "PHYS_OFFSET" is 0x0 but the calculated "ramstart" is
> > > > > > > not. As the prerequisite of custom memory map has been removed, this results
> > > > > > > in the full memory range of 0x0 - 0x8000000 to be marked as reserved for this
> > > > > > > platform.
> > > > > >
> > > > > > and where is the problem here ?
> > > > > Turns out this was already attempted to be upstreamed - not clear why
> > > > > it wasn't merged. Context:
> > > > > https://lore.kernel.org/linux-mips/6504517.U6H5IhoIOn@loki/
> > > > >
> > > > > I hope the thread above helps you understand the problem.
> > > >
> > > > The memory initialization was a bit different then. Do you still see the
> > > > same problem?
> > > Thanks for asking. I obtained a RT2880 device and gave it a try. It
> > > hangs at boot without this patch, however selecting
> >
> > can you provide debug logs with memblock=debug for both good and bad
> > kernels ? I'm curious what's the reason for failing allocation...
> Sorry for taking a while to respond. See attached.
> FWIW, it seems these are the lines that stand out in hang.log:
> [    0.000000] memblock_reserve: [0x00000000-0x07ffffff] setup_arch+0x214/0x5d8
> [    0.000000] Wasting 1048576 bytes for tracking 32768 unused pages
> ...
> [    0.000000]  reserved[0x0]    [0x00000000-0x087137aa], 0x087137ab
> bytes flags: 0x0
Just to be clear, good.log is mips-next tip (dbd815c0dcca) and
hang.log is the same with MIPS_AUTO_PFN_OFFSET _NOT_ selected.

Ilya