From: "Jose R. Santos" <jrsantos@austin.ibm.com>
I was looking at the recent for >MAX_ORDER hash tables but it seems that
the patch limits the number of entries to what it thinks are good values
and the i/dhash_entries cmdline options can not exceed this.
This seems to limit the usability of the patch on systems were larger
allocations that the ones the kernel calculates are desired.
- Make ihash_entries and dhash_entries cmdline option behave like it use to.
- Remove MAX_SYS_HASH_TABLE_ORDER. Limit the max size to 1/16 the total
number of pages.
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-sparc64-akpm/include/linux/mmzone.h | 12 ---------
25-sparc64-akpm/mm/page_alloc.c | 43 ++++++++++++++++-----------------
2 files changed, 21 insertions(+), 34 deletions(-)
diff -puN include/linux/mmzone.h~making-i-dhash_entries-cmdline-work-as-it-use-to include/linux/mmzone.h
--- 25-sparc64/include/linux/mmzone.h~making-i-dhash_entries-cmdline-work-as-it-use-to 2004-07-31 20:57:37.994483920 -0700
+++ 25-sparc64-akpm/include/linux/mmzone.h 2004-07-31 20:57:38.001482856 -0700
@@ -20,18 +20,6 @@
#define MAX_ORDER CONFIG_FORCE_MAX_ZONEORDER
#endif
-/*
- * system hash table size limits
- * - on large memory machines, we may want to allocate a bigger hash than that
- * permitted by MAX_ORDER, so we allocate with the bootmem allocator, and are
- * limited to this size
- */
-#if MAX_ORDER > 14
-#define MAX_SYS_HASH_TABLE_ORDER MAX_ORDER
-#else
-#define MAX_SYS_HASH_TABLE_ORDER 14
-#endif
-
struct free_area {
struct list_head free_list;
unsigned long *map;
diff -puN mm/page_alloc.c~making-i-dhash_entries-cmdline-work-as-it-use-to mm/page_alloc.c
--- 25-sparc64/mm/page_alloc.c~making-i-dhash_entries-cmdline-work-as-it-use-to 2004-07-31 20:57:37.995483768 -0700
+++ 25-sparc64-akpm/mm/page_alloc.c 2004-07-31 20:57:38.003482552 -0700
@@ -1993,31 +1993,30 @@ void *__init alloc_large_system_hash(con
unsigned int *_hash_shift,
unsigned int *_hash_mask)
{
- unsigned long mem, max, log2qty, size;
+ unsigned long max, log2qty, size;
void *table;
- /* round applicable memory size up to nearest megabyte */
- mem = consider_highmem ? nr_all_pages : nr_kernel_pages;
- mem += (1UL << (20 - PAGE_SHIFT)) - 1;
- mem >>= 20 - PAGE_SHIFT;
- mem <<= 20 - PAGE_SHIFT;
-
- /* limit to 1 bucket per 2^scale bytes of low memory (rounded up to
- * nearest power of 2 in size) */
- if (scale > PAGE_SHIFT)
- mem >>= (scale - PAGE_SHIFT);
- else
- mem <<= (PAGE_SHIFT - scale);
-
- mem = 1UL << (long_log2(mem) + 1);
-
- /* limit allocation size */
- max = (1UL << (PAGE_SHIFT + MAX_SYS_HASH_TABLE_ORDER)) / bucketsize;
- if (max > mem)
- max = mem;
-
/* allow the kernel cmdline to have a say */
- if (!numentries || numentries > max)
+ if (!numentries) {
+ /* round applicable memory size up to nearest megabyte */
+ numentries = consider_highmem ? nr_all_pages : nr_kernel_pages;
+ numentries += (1UL << (20 - PAGE_SHIFT)) - 1;
+ numentries >>= 20 - PAGE_SHIFT;
+ numentries <<= 20 - PAGE_SHIFT;
+
+ /* limit to 1 bucket per 2^scale bytes of low memory */
+ if (scale > PAGE_SHIFT)
+ numentries >>= (scale - PAGE_SHIFT);
+ else
+ numentries <<= (PAGE_SHIFT - scale);
+ }
+ /* rounded up to nearest power of 2 in size */
+ numentries = 1UL << (long_log2(numentries) + 1);
+
+ /* limit allocation size to 1/16 total memory */
+ max = ((nr_all_pages << PAGE_SHIFT)/16) / bucketsize;
+
+ if (numentries > max)
numentries = max;
log2qty = long_log2(numentries);
_