lkml.org 
[lkml]   [2005]   [Sep]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
SubjectRe: inconsistent mmap and get_user_pages with hugetlbfs on ppc64
From
Date
On Fri, 2005-09-16 at 18:52 -0400, Sexton, Matt wrote:
> On a ppc64 platform running 2.6.13-1, the virtual to physical mapping
> established by mmap'ing a hugetlbfs file does not seem to match the
> mapping described by get_user_pages().

Matt, you might want to try with something newer like 2.6.14-rc2-git6
and the following patch from Ben Herrenschmidt. We found a few issues
with the hardware hash table and they should be fixed now (with the
patch below). Is the system you are testing on LPAR or native? Power4
or 5?

--- snip ---

My previous patch fixing invalidation of huge PTEs wasn't good enough,
we still had an issue if a PTE invalidation batch contained both small
and large pages. This patch fixes this by making sure the batch is
flushed if the page size fed to it changes.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Index: linux-work/arch/ppc64/mm/hash_native.c
===================================================================
--- linux-work.orig/arch/ppc64/mm/hash_native.c 2005-09-27 11:43:27.000000000 +1000
+++ linux-work/arch/ppc64/mm/hash_native.c 2005-09-27 11:48:06.000000000 +1000
@@ -343,7 +343,7 @@
hpte_t *hptep;
unsigned long hpte_v;
struct ppc64_tlb_batch *batch = &__get_cpu_var(ppc64_tlb_batch);
- unsigned long large;
+ unsigned long large = batch->large;

local_irq_save(flags);

@@ -356,7 +356,6 @@

va = (vsid << 28) | (batch->addr[i] & 0x0fffffff);
batch->vaddr[j] = va;
- large = pte_huge(batch->pte[i]);
if (large)
vpn = va >> HPAGE_SHIFT;
else
@@ -406,7 +405,7 @@
asm volatile("ptesync":::"memory");

for (i = 0; i < j; i++)
- __tlbie(batch->vaddr[i], 0);
+ __tlbie(batch->vaddr[i], large);

asm volatile("eieio; tlbsync; ptesync":::"memory");

Index: linux-work/arch/ppc64/mm/tlb.c
===================================================================
--- linux-work.orig/arch/ppc64/mm/tlb.c 2005-09-27 11:43:27.000000000 +1000
+++ linux-work/arch/ppc64/mm/tlb.c 2005-09-27 11:47:35.000000000 +1000
@@ -143,7 +143,8 @@
* up scanning and resetting referenced bits then our batch context
* will change mid stream.
*/
- if (unlikely(i != 0 && context != batch->context)) {
+ if (i != 0 && (context != batch->context ||
+ batch->large != pte_huge(pte))) {
flush_tlb_pending();
i = 0;
}
@@ -151,6 +152,7 @@
if (i == 0) {
batch->context = context;
batch->mm = mm;
+ batch->large = pte_huge(pte);
}
batch->pte[i] = __pte(pte);
batch->addr[i] = addr;
Index: linux-work/include/asm-ppc64/tlbflush.h
===================================================================
--- linux-work.orig/include/asm-ppc64/tlbflush.h 2005-09-27 11:43:27.000000000 +1000
+++ linux-work/include/asm-ppc64/tlbflush.h 2005-09-27 11:45:09.000000000 +1000
@@ -25,6 +25,7 @@
pte_t pte[PPC64_TLB_BATCH_NR];
unsigned long addr[PPC64_TLB_BATCH_NR];
unsigned long vaddr[PPC64_TLB_BATCH_NR];
+ unsigned int large;
};
DECLARE_PER_CPU(struct ppc64_tlb_batch, ppc64_tlb_batch);

--
Adam Litke - (agl at us.ibm.com)
IBM Linux Technology Center

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-09-29 19:54    [W:0.085 / U:0.076 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site