* [RFC PATCH v3 2/3] powerpc: Split the code trying to insert hpte repeatedly as an helper function
2013-04-16 2:53 [RFC PATCH v3 1/3] powerpc: Move the setting of rflags out of loop in __hash_page_huge Li Zhong
@ 2013-04-16 2:53 ` Li Zhong
2013-04-16 2:53 ` [RFC PATCH v3 3/3] powerpc: Try to insert the hptes repeatedly in kernel_map_linear_page() Li Zhong
1 sibling, 0 replies; 3+ messages in thread
From: Li Zhong @ 2013-04-16 2:53 UTC (permalink / raw)
To: linuxppc-dev; +Cc: paulus, Li Zhong
Move the logic trying to insert hpte in __hash_page_huge() to an helper
function, so it could also be used by others.
Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
---
arch/powerpc/mm/hash_utils_64.c | 35 ++++++++++++++++++++++++++++++++++
arch/powerpc/mm/hugetlbpage-hash64.c | 31 ++++++------------------------
2 files changed, 41 insertions(+), 25 deletions(-)
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index f410c3e..ead9fa8 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -1230,6 +1230,41 @@ void low_hash_fault(struct pt_regs *regs, unsigned long address, int rc)
bad_page_fault(regs, address, SIGBUS);
}
+long hpte_insert_repeating(unsigned long hash, unsigned long vpn,
+ unsigned long pa, unsigned long rflags,
+ unsigned long vflags, int psize, int ssize)
+{
+ unsigned long hpte_group;
+ long slot;
+
+repeat:
+ hpte_group = ((hash & htab_hash_mask) *
+ HPTES_PER_GROUP) & ~0x7UL;
+
+ /* Insert into the hash table, primary slot */
+ slot = ppc_md.hpte_insert(hpte_group, vpn, pa, rflags, vflags,
+ psize, ssize);
+
+ /* Primary is full, try the secondary */
+ if (unlikely(slot == -1)) {
+ hpte_group = ((~hash & htab_hash_mask) *
+ HPTES_PER_GROUP) & ~0x7UL;
+ slot = ppc_md.hpte_insert(hpte_group, vpn, pa, rflags,
+ vflags | HPTE_V_SECONDARY,
+ psize, ssize);
+ if (slot == -1) {
+ if (mftb() & 0x1)
+ hpte_group = ((hash & htab_hash_mask) *
+ HPTES_PER_GROUP)&~0x7UL;
+
+ ppc_md.hpte_remove(hpte_group);
+ goto repeat;
+ }
+ }
+
+ return slot;
+}
+
#ifdef CONFIG_DEBUG_PAGEALLOC
static void kernel_map_linear_page(unsigned long vaddr, unsigned long lmi)
{
diff --git a/arch/powerpc/mm/hugetlbpage-hash64.c b/arch/powerpc/mm/hugetlbpage-hash64.c
index edb4129..b913f41 100644
--- a/arch/powerpc/mm/hugetlbpage-hash64.c
+++ b/arch/powerpc/mm/hugetlbpage-hash64.c
@@ -14,6 +14,10 @@
#include <asm/cacheflush.h>
#include <asm/machdep.h>
+extern long hpte_insert_repeating(unsigned long hash, unsigned long vpn,
+ unsigned long pa, unsigned long rlags,
+ unsigned long vflags, int psize, int ssize);
+
int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid,
pte_t *ptep, unsigned long trap, int local, int ssize,
unsigned int shift, unsigned int mmu_psize)
@@ -83,7 +87,6 @@ int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid,
if (likely(!(old_pte & _PAGE_HASHPTE))) {
unsigned long hash = hpt_hash(vpn, shift, ssize);
- unsigned long hpte_group;
pa = pte_pfn(__pte(old_pte)) << PAGE_SHIFT;
@@ -97,30 +100,8 @@ int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid,
rflags |= (new_pte & (_PAGE_WRITETHRU | _PAGE_NO_CACHE |
_PAGE_COHERENT | _PAGE_GUARDED));
-repeat:
- hpte_group = ((hash & htab_hash_mask) *
- HPTES_PER_GROUP) & ~0x7UL;
-
- /* Insert into the hash table, primary slot */
- slot = ppc_md.hpte_insert(hpte_group, vpn, pa, rflags, 0,
- mmu_psize, ssize);
-
- /* Primary is full, try the secondary */
- if (unlikely(slot == -1)) {
- hpte_group = ((~hash & htab_hash_mask) *
- HPTES_PER_GROUP) & ~0x7UL;
- slot = ppc_md.hpte_insert(hpte_group, vpn, pa, rflags,
- HPTE_V_SECONDARY,
- mmu_psize, ssize);
- if (slot == -1) {
- if (mftb() & 0x1)
- hpte_group = ((hash & htab_hash_mask) *
- HPTES_PER_GROUP)&~0x7UL;
-
- ppc_md.hpte_remove(hpte_group);
- goto repeat;
- }
- }
+ slot = hpte_insert_repeating(hash, vpn, pa, rflags, 0,
+ mmu_psize, ssize);
/*
* Hypervisor failure. Restore old pte and return -1
--
1.7.9.5
^ permalink raw reply related [flat|nested] 3+ messages in thread* [RFC PATCH v3 3/3] powerpc: Try to insert the hptes repeatedly in kernel_map_linear_page()
2013-04-16 2:53 [RFC PATCH v3 1/3] powerpc: Move the setting of rflags out of loop in __hash_page_huge Li Zhong
2013-04-16 2:53 ` [RFC PATCH v3 2/3] powerpc: Split the code trying to insert hpte repeatedly as an helper function Li Zhong
@ 2013-04-16 2:53 ` Li Zhong
1 sibling, 0 replies; 3+ messages in thread
From: Li Zhong @ 2013-04-16 2:53 UTC (permalink / raw)
To: linuxppc-dev; +Cc: paulus, Li Zhong
This patch fixes the following oops, which could be trigged by build the kernel
with many concurrent threads, under CONFIG_DEBUG_PAGEALLOC.
hpte_insert() might return -1, indicating that the bucket (primary here)
is full. We are not necessarily reporting a BUG in this case. Instead, we could
try repeatedly (try secondary, remove and try again) until we find a slot.
[ 543.075675] ------------[ cut here ]------------
[ 543.075701] kernel BUG at arch/powerpc/mm/hash_utils_64.c:1239!
[ 543.075714] Oops: Exception in kernel mode, sig: 5 [#1]
[ 543.075722] PREEMPT SMP NR_CPUS=16 DEBUG_PAGEALLOC NUMA pSeries
[ 543.075741] Modules linked in: binfmt_misc ehea
[ 543.075759] NIP: c000000000036eb0 LR: c000000000036ea4 CTR: c00000000005a594
[ 543.075771] REGS: c0000000a90832c0 TRAP: 0700 Not tainted (3.8.0-next-20130222)
[ 543.075781] MSR: 8000000000029032 <SF,EE,ME,IR,DR,RI> CR: 22224482 XER: 00000000
[ 543.075816] SOFTE: 0
[ 543.075823] CFAR: c00000000004c200
[ 543.075830] TASK = c0000000e506b750[23934] 'cc1' THREAD: c0000000a9080000 CPU: 1
GPR00: 0000000000000001 c0000000a9083540 c000000000c600a8 ffffffffffffffff
GPR04: 0000000000000050 fffffffffffffffa c0000000a90834e0 00000000004ff594
GPR08: 0000000000000001 0000000000000000 000000009592d4d8 c000000000c86854
GPR12: 0000000000000002 c000000006ead300 0000000000a51000 0000000000000001
GPR16: f000000003354380 ffffffffffffffff ffffffffffffff80 0000000000000000
GPR20: 0000000000000001 c000000000c600a8 0000000000000001 0000000000000001
GPR24: 0000000003354380 c000000000000000 0000000000000000 c000000000b65950
GPR28: 0000002000000000 00000000000cd50e 0000000000bf50d9 c000000000c7c230
[ 543.076005] NIP [c000000000036eb0] .kernel_map_pages+0x1e0/0x3f8
[ 543.076016] LR [c000000000036ea4] .kernel_map_pages+0x1d4/0x3f8
[ 543.076025] Call Trace:
[ 543.076033] [c0000000a9083540] [c000000000036ea4] .kernel_map_pages+0x1d4/0x3f8 (unreliable)
[ 543.076053] [c0000000a9083640] [c000000000167638] .get_page_from_freelist+0x6cc/0x8dc
[ 543.076067] [c0000000a9083800] [c000000000167a48] .__alloc_pages_nodemask+0x200/0x96c
[ 543.076082] [c0000000a90839c0] [c0000000001ade44] .alloc_pages_vma+0x160/0x1e4
[ 543.076098] [c0000000a9083a80] [c00000000018ce04] .handle_pte_fault+0x1b0/0x7e8
[ 543.076113] [c0000000a9083b50] [c00000000018d5a8] .handle_mm_fault+0x16c/0x1a0
[ 543.076129] [c0000000a9083c00] [c0000000007bf1dc] .do_page_fault+0x4d0/0x7a4
[ 543.076144] [c0000000a9083e30] [c0000000000090e8] handle_page_fault+0x10/0x30
[ 543.076155] Instruction dump:
[ 543.076163] 7c630038 78631d88 e80a0000 f8410028 7c0903a6 e91f01de e96a0010 e84a0008
[ 543.076192] 4e800421 e8410028 7c7107b4 7a200fe0 <0b000000> 7f63db78 48785781 60000000
[ 543.076224] ---[ end trace bd5807e8d6ae186b ]---
Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
---
arch/powerpc/mm/hash_utils_64.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index ead9fa8..1ed4419 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -1268,21 +1268,22 @@ repeat:
#ifdef CONFIG_DEBUG_PAGEALLOC
static void kernel_map_linear_page(unsigned long vaddr, unsigned long lmi)
{
- unsigned long hash, hpteg;
+ unsigned long hash;
unsigned long vsid = get_kernel_vsid(vaddr, mmu_kernel_ssize);
unsigned long vpn = hpt_vpn(vaddr, vsid, mmu_kernel_ssize);
unsigned long mode = htab_convert_pte_flags(PAGE_KERNEL);
- int ret;
+ long ret;
hash = hpt_hash(vpn, PAGE_SHIFT, mmu_kernel_ssize);
- hpteg = ((hash & htab_hash_mask) * HPTES_PER_GROUP);
/* Don't create HPTE entries for bad address */
if (!vsid)
return;
- ret = ppc_md.hpte_insert(hpteg, vpn, __pa(vaddr),
- mode, HPTE_V_BOLTED,
- mmu_linear_psize, mmu_kernel_ssize);
+
+ ret = hpte_insert_repeating(hash, vpn, __pa(vaddr), mode,
+ HPTE_V_BOLTED,
+ mmu_linear_psize, mmu_kernel_ssize);
+
BUG_ON (ret < 0);
spin_lock(&linear_map_hash_lock);
BUG_ON(linear_map_hash_slots[lmi] & 0x80);
--
1.7.9.5
^ permalink raw reply related [flat|nested] 3+ messages in thread