From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
To: benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au
Cc: linuxppc-dev@lists.ozlabs.org,
"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Subject: [PATCH] powerpc/mm: Update the FORCE_MAX_ZONEORDER range to enable hugetlb
Date: Mon, 19 Sep 2016 23:01:33 +0530 [thread overview]
Message-ID: <1474306293-15390-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> (raw)
For hugetlb to work with 4K page size, we need the MAX_ORDER to be more
than 13. When switching from a 64K page size to 4K linux page size using
make nconfig, we endup with a CONFIG_FORCE_MAX_ZONEORDER value of 9.
This results in 16M hugepage to be considered as a gigantic huge page
which inturn can result in failure to setup hugepages if gigantic
hugepage support is not enabled.
This also results in kernel crash with 4K radix configuration. We
hit the below BUG_ON on radix
kernel BUG at mm/huge_memory.c:364!
Oops: Exception in kernel mode, sig: 5 [#1]
SMP NR_CPUS=2048 NUMA PowerNV
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.8.0-rc1-00006-gbae9cc6 #1
task: c0000000f1af8000 task.stack: c0000000f1aec000
NIP: c000000000c5fa0c LR: c000000000c5f9d8 CTR: c000000000c5f9a4
REGS: c0000000f1aef920 TRAP: 0700 Not tainted (4.8.0-rc1-00006-gbae9cc6)
MSR: 9000000102029033 <SF,HV,VEC,EE,ME,IR,DR,RI,LE,TM[E]> CR: 24000844 XER: 00000000
CFAR: c000000000c5f9e0 SOFTE: 1
.....
NIP [c000000000c5fa0c] hugepage_init+0x68/0x238
LR [c000000000c5f9d8] hugepage_init+0x34/0x238
Fixes: a7ee539584acf ("powerpc/Kconfig: Update config option based on page size")
Reported-by: Santhosh <santhog4@linux.vnet.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
arch/powerpc/Kconfig | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 927d2ab2ce08..792cb1768c8f 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -637,7 +637,7 @@ config FORCE_MAX_ZONEORDER
int "Maximum zone order"
range 8 9 if PPC64 && PPC_64K_PAGES
default "9" if PPC64 && PPC_64K_PAGES
- range 9 13 if PPC64 && !PPC_64K_PAGES
+ range 13 13 if PPC64 && !PPC_64K_PAGES
default "13" if PPC64 && !PPC_64K_PAGES
range 9 64 if PPC32 && PPC_16K_PAGES
default "9" if PPC32 && PPC_16K_PAGES
--
2.7.4
next reply other threads:[~2016-09-19 17:31 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-19 17:31 Aneesh Kumar K.V [this message]
2016-09-20 1:29 ` [PATCH] powerpc/mm: Update the FORCE_MAX_ZONEORDER range to enable hugetlb Balbir Singh
2016-09-20 2:52 ` Aneesh Kumar K.V
2016-09-20 3:13 ` Balbir Singh
2016-09-20 13:07 ` Michael Ellerman
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