On 27.02.2007 [10:47:31 +1100], David Gibson wrote:
> On Mon, Feb 26, 2007 at 03:21:26PM -0800, Nishanth Aravamudan wrote:
> > Author: Nishanth Aravamudan <[EMAIL PROTECTED]>
> > Date: Mon Feb 26 15:17:54 2007 -0800
> >
> > hugeutils: add address parameter to hugetlbfs_vaddr_granularity
> >
> > On ppc64, the actual granularity of hugepage requests depends on the
> > address in question. Specify the three cases (0-4G, 4G-1TB, 1TB+) in the
> > function. This is useful for the partial_remap code, as it would
> > (effectively) never run on ppc64 otherwise (would need a 1TB or larger
> > segment, without relinking).
>
> I've thought about doing something like this before. However, the
> semantics as they stand are a little bit fuzzy. What I'd prefer, if
> you want to get finer-grained information about the page-size regions
> is a pair of functions to find the end and beginning of a page-size
> slice, given an address. So:
>
> void *hugetlbfs_slice_end(void *addr);
> void *hugetlbfs_slice_start(void *addr);
>
> The "slice" terminology is something BenH has started using for these
> address space regionsin some recent kernel patches.
I'm willing to believe I'm doing something incredibly stupid, but here's
my patch. I had to use a bunch of macros, as I was getting a headache
from all the casts and the constants. How do I make this cleaner? Or do
I give up on this?
Signed-off-by: Nishanth Aravamudan <[EMAIL PROTECTED]>
diff --git a/hugetlbfs.h b/hugetlbfs.h
index 966e57c..1a5d8b7 100644
--- a/hugetlbfs.h
+++ b/hugetlbfs.h
@@ -22,7 +22,9 @@
#define HUGETLBFS_MAGIC 0x958458f6
long gethugepagesize(void);
-long hugetlbfs_vaddr_granularity(void);
+void *hugetlbfs_slice_start(void *);
+void *hugetlbfs_slice_end(void *);
+long hugetlbfs_vaddr_granularity(void *addr);
int hugetlbfs_test_path(const char *mount);
const char *hugetlbfs_find_path(void);
int hugetlbfs_unlinked_fd(void);
diff --git a/hugeutils.c b/hugeutils.c
index 9af92b9..c030daf 100644
--- a/hugeutils.c
+++ b/hugeutils.c
@@ -114,12 +114,68 @@ long gethugepagesize(void)
return hpage_size;
}
-long hugetlbfs_vaddr_granularity(void)
+#define twofiftysixMB (1UL << 28)
+#define fourGB (1UL << 32)
+#define oneTB (1UL << 40)
+#define ALIGN_PTR_DOWN(x, a) \
+ ((void *)((unsigned long)(x) & ~((a) - 1)))
+#define ALIGN_PTR_UP(x, a) \
+ ((void *)(((unsigned long)(x) + (a) - 1) & ~((a) - 1)))
+
+/*
+ * Return the address of the start and end of the hugetlb slice
+ * containing @addr. A slice is a range of addresses, start inclusive
+ * and end exclusive.
+ */
+void *hugetlbfs_slice_start(void *addr) {
+#if defined(__powerpc64__)
+ if (addr < (void *)fourGB)
+ return ALIGN_PTR_DOWN(addr, twofiftysixMB);
+ else if (addr < (void *)oneTB)
+ return (void *)fourGB;
+ else
+ return ALIGN_PTR_DOWN(addr, oneTB);
+#elif defined(__powerpc__)
+ return ALIGN_PTR_DOWN(addr, twofiftysixMB);
+#else
+ long hpage_size = gethugepagesize();
+ if (hpage_size)
+ return ALIGN_PTR_DOWN(addr, hpage_size);
+ else
+ return NULL;
+#endif
+}
+
+void *hugetlbfs_slice_end(void *addr) {
+#if defined(__powerpc64__)
+ if (addr < (void *)fourGB)
+ return ALIGN_PTR_UP(addr, twofiftysixMB);
+ else if (addr < (void *)oneTB);
+ return (void *)oneTB;
+ else
+ return ALIGN_PTR_UP(addr, oneTB);
+#elif defined(__powerpc__)
+ return ALIGN_PTR_UP(addr, twofiftysixMB);
+#else
+ long hpage_size = gethugepagesize();
+ if (hpage_size)
+ return ALIGN_PTR_UP(addr, hpage_size);
+ else
+ return NULL;
+#endif
+}
+
+long hugetlbfs_vaddr_granularity(void *addr)
{
#if defined(__powerpc64__)
- return (1L << 40);
+ if (addr < (void *)fourGB)
+ return twofiftysixMB;
+ else if (addr < (void *)oneTB)
+ return oneTB - fourGB;
+ else
+ return 1TB;
#elif defined(__powerpc__)
- return (1L << 28);
+ return twofiftysixMB;
#else
return gethugepagesize();
#endif
diff --git a/morecore.c b/morecore.c
index 25c2d27..7efb174 100644
--- a/morecore.c
+++ b/morecore.c
@@ -166,7 +166,7 @@ static void __attribute__((constructor))
setup_morecore(void)
}
} else {
heapaddr = (unsigned long)sbrk(0);
- heapaddr = ALIGN(heapaddr, hugetlbfs_vaddr_granularity());
+ heapaddr = ALIGN(heapaddr, hugetlbfs_vaddr_granularity((void
*)heapaddr));
}
DEBUG("setup_morecore(): heapaddr = 0x%lx\n", heapaddr);
--
Nishanth Aravamudan <[EMAIL PROTECTED]>
IBM Linux Technology Center
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