From: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
To: Qian Cai <cai@lca.pw>, catalin.marinas@arm.com
Cc: f.fainelli@gmail.com, mbrugger@suse.com, marc.zyngier@arm.com,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org, Rob Herring <robh+dt@kernel.org>,
linux-rpi-kernel@lists.infradead.org, m.szyprowski@samsung.com,
Robin Murphy <Robin.Murphy@arm.com>,
phill@raspberrypi.org, will@kernel.org,
Christoph Hellwig <hch@lst.de>,
linux-arm-kernel@lists.infradead.org, wahrenst@gmx.net
Subject: Re: [PATCH v6 3/4] arm64: use both ZONE_DMA and ZONE_DMA32
Date: Tue, 22 Oct 2019 13:23:32 +0200 [thread overview]
Message-ID: <1956a2c8f4911b2a7e2ba3c53506c0f06efb93f8.camel@suse.de> (raw)
In-Reply-To: <AA6D37F1-A1B3-4EC4-8620-007095168BC7@lca.pw>
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On Mon, 2019-10-21 at 16:36 -0400, Qian Cai wrote:
> I managed to get more information here,
>
> [ 0.000000] cma: dma_contiguous_reserve(limit c0000000)
> [ 0.000000] cma: dma_contiguous_reserve: reserving 64 MiB for global area
> [ 0.000000] cma: cma_declare_contiguous(size 0x0000000004000000, base
> 0x0000000000000000, limit 0x00000000c0000000 alignment 0x0000000000000000)
> [ 0.000000] cma: Failed to reserve 512 MiB
>
> Full dmesg:
>
> https://cailca.github.io/files/dmesg.txt
OK I got it, reproduced it too.
Here are the relevant logs:
[ 0.000000] DMA [mem 0x00000000802f0000-0x00000000bfffffff]
[ 0.000000] DMA32 [mem 0x00000000c0000000-0x00000000ffffffff]
[ 0.000000] Normal [mem 0x0000000100000000-0x00000097fcffffff]
As you can see ZONE_DMA spans from 0x00000000802f0000-0x00000000bfffffff which
is slightly smaller than 1GB.
[ 0.000000] crashkernel reserved: 0x000000009fe00000 - 0x00000000bfe00000 (512 MB)
Here crashkernel reserved 512M in ZONE_DMA.
[ 0.000000] cma: Failed to reserve 512 MiB
CMA tried to allocate 512M in ZONE_DMA which fails as there is no enough space.
Makes sense.
A fix could be moving crashkernel reservations after CMA and then if unable to
fit in ZONE_DMA try ZONE_DMA32 before bailing out. Maybe it's a little over the
top, yet although most devices will be fine with ZONE_DMA32, the RPi4 needs
crashkernel to be reserved in ZONE_DMA.
My knowledge of Kdump is limited, so I'd love to see what Catalin has to say.
Here's a tested patch of what I'm proposing:
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 120c26af916b..49f3c3a34ae2 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -76,6 +76,7 @@ phys_addr_t arm64_dma32_phys_limit __ro_after_init;
static void __init reserve_crashkernel(void)
{
unsigned long long crash_base, crash_size;
+ phys_addr_t limit = arm64_dma_phys_limit;
int ret;
ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
@@ -86,11 +87,14 @@ static void __init reserve_crashkernel(void)
crash_size = PAGE_ALIGN(crash_size);
+again:
if (crash_base == 0) {
/* Current arm64 boot protocol requires 2MB alignment */
- crash_base = memblock_find_in_range(0, ARCH_LOW_ADDRESS_LIMIT,
- crash_size, SZ_2M);
- if (crash_base == 0) {
+ crash_base = memblock_find_in_range(0, limit, crash_size,
SZ_2M);
+ if (!crash_base && limit == arm64_dma_phys_limit) {
+ limit = arm64_dma32_phys_limit;
+ goto again;
+ } else if (!crash_base && limit == arm64_dma32_phys_limit) {
pr_warn("cannot allocate crashkernel (size:0x%llx)\n",
crash_size);
return;
@@ -448,13 +452,13 @@ void __init arm64_memblock_init(void)
else
arm64_dma32_phys_limit = PHYS_MASK + 1;
- reserve_crashkernel();
-
reserve_elfcorehdr();
high_memory = __va(memblock_end_of_DRAM() - 1) + 1;
dma_contiguous_reserve(arm64_dma_phys_limit ? : arm64_dma32_phys_limit);
+
+ reserve_crashkernel();
}
void __init bootmem_init(void)
Regards,
Nicolas
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next prev parent reply other threads:[~2019-10-22 11:23 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-11 18:25 [PATCH v6 0/4] Raspberry Pi 4 DMA addressing support Nicolas Saenz Julienne
2019-09-11 18:25 ` [PATCH v6 1/4] arm64: mm: use arm64_dma_phys_limit instead of calling max_zone_dma_phys() Nicolas Saenz Julienne
2019-09-11 18:25 ` [PATCH v6 2/4] arm64: rename variables used to calculate ZONE_DMA32's size Nicolas Saenz Julienne
2019-09-11 18:25 ` [PATCH v6 3/4] arm64: use both ZONE_DMA and ZONE_DMA32 Nicolas Saenz Julienne
2019-10-21 14:15 ` Qian Cai
2019-10-21 14:34 ` Nicolas Saenz Julienne
2019-10-21 14:46 ` Qian Cai
2019-10-21 17:01 ` Nicolas Saenz Julienne
2019-10-21 17:25 ` Qian Cai
2019-10-21 17:55 ` Nicolas Saenz Julienne
2019-10-21 20:36 ` Qian Cai
2019-10-22 11:23 ` Nicolas Saenz Julienne [this message]
2019-10-23 7:11 ` Matthias Brugger
2019-10-31 15:51 ` Catalin Marinas
2019-10-31 16:04 ` Nicolas Saenz Julienne
2019-10-31 18:02 ` Catalin Marinas
2019-10-31 18:11 ` Nicolas Saenz Julienne
2019-10-31 18:13 ` Catalin Marinas
2019-12-03 5:08 ` John Stultz
2019-12-03 5:38 ` John Stultz
2019-12-03 6:03 ` John Stultz
2019-12-03 10:12 ` Will Deacon
2019-12-03 11:19 ` Catalin Marinas
2019-09-11 18:25 ` [PATCH v6 4/4] mm: refresh ZONE_DMA and ZONE_DMA32 comments in 'enum zone_type' Nicolas Saenz Julienne
2019-10-01 16:05 ` [PATCH v6 0/4] Raspberry Pi 4 DMA addressing support Catalin Marinas
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