Tony,
This patch shrinks the quicklist based upon free memory on the node
instead of the high/low water marks. I have written it to enable
preemption periodically and recalculate the amount to shrink every
time we have freed enough pages that the quicklist size should have grown.
I retain the scan of free memory on the node as other processes may be
draining at the same time as we are adding.
Signed-off-by: Robin Holt <[EMAIL PROTECTED]>
No noticable performance change on lmbench. For completeness sake, here
are the before and after numbers:
Before:
Process fork+exit: 180.8065 microseconds
Process fork+exit: 182.4286 microseconds
Process fork+exit: 184.0333 microseconds
Process fork+exit: 183.3226 microseconds
Process fork+exit: 182.6333 microseconds
Process fork+exit: 183.4000 microseconds
Process fork+exit: 183.4667 microseconds
Process fork+exit: 182.1935 microseconds
Process fork+exit: 182.0667 microseconds
Process fork+exit: 183.7742 microseconds
Process fork+execve: 188.1667 microseconds
Process fork+execve: 188.6071 microseconds
Process fork+execve: 187.5333 microseconds
Process fork+execve: 188.9286 microseconds
Process fork+execve: 188.4333 microseconds
Process fork+execve: 187.6000 microseconds
Process fork+execve: 187.6333 microseconds
Process fork+execve: 188.5333 microseconds
Process fork+execve: 187.9655 microseconds
Process fork+execve: 186.3667 microseconds
After:
Process fork+exit: 182.3793 microseconds
Process fork+exit: 183.0667 microseconds
Process fork+exit: 182.9333 microseconds
Process fork+exit: 183.7742 microseconds
Process fork+exit: 182.9333 microseconds
Process fork+exit: 183.6774 microseconds
Process fork+exit: 182.2903 microseconds
Process fork+exit: 183.2667 microseconds
Process fork+exit: 181.0333 microseconds
Process fork+exit: 183.0000 microseconds
Process fork+execve: 187.9333 microseconds
Process fork+execve: 188.2000 microseconds
Process fork+execve: 188.5333 microseconds
Process fork+execve: 188.7333 microseconds
Process fork+execve: 189.0000 microseconds
Process fork+execve: 188.8667 microseconds
Process fork+execve: 187.3333 microseconds
Process fork+execve: 189.5172 microseconds
Process fork+execve: 188.4333 microseconds
Process fork+execve: 188.7667 microseconds
init.c | 48 ++++++++++++++++++++++++------------------------
1 files changed, 24 insertions(+), 24 deletions(-)
Index: linux-2.6/arch/ia64/mm/init.c
===================================================================
--- linux-2.6.orig/arch/ia64/mm/init.c 2005-03-01 10:20:38.289030938 -0600
+++ linux-2.6/arch/ia64/mm/init.c 2005-03-01 10:20:38.374967413 -0600
@@ -50,24 +50,48 @@
EXPORT_SYMBOL(vmem_map);
#endif
-static int pgt_cache_water[2] = { 25, 50 };
-
struct page *zero_page_memmap_ptr; /* map entry for zero page */
EXPORT_SYMBOL(zero_page_memmap_ptr);
+#define quicklist_size local_cpu_data->pgtable_quicklist_size
+#define MIN_PGT_PAGES 25UL
+/* This value was chosen to prevent a large block of frees to hold off timer
ticks */
+#define NODE_FREE_PAGES_SHIFT 4
+
+static inline long
+max_pgt_pages (void)
+{
+ u64 node_free_pages, max_pgt_pages;
+
+#ifndef CONFIG_NUMA
+ node_free_pages = nr_free_pages();
+#else
+ node_free_pages = nr_free_pages_pgdat(NODE_DATA(numa_node_id()));
+#endif
+ max_pgt_pages = node_free_pages >> NODE_FREE_PAGES_SHIFT;
+ max_pgt_pages = max(max_pgt_pages, MIN_PGT_PAGES);
+ return max_pgt_pages;
+}
+
+
void
check_pgt_cache (void)
{
- int low, high;
+ long pages_to_free;
- low = pgt_cache_water[0];
- high = pgt_cache_water[1];
+ if (unlikely(quicklist_size <= MIN_PGT_PAGES))
+ return;
preempt_disable();
- if (local_cpu_data->pgtable_quicklist_size > (u64) high) {
- do {
+ pages_to_free = quicklist_size - max_pgt_pages();
+ while (unlikely(pages_to_free > 0)) {
+ pages_to_free = min(pages_to_free, 1L << NODE_FREE_PAGES_SHIFT);
+ while (pages_to_free--) {
free_page((unsigned long)pgtable_quicklist_alloc());
- } while (local_cpu_data->pgtable_quicklist_size > (u64) low);
+ }
+ preempt_enable();
+ preempt_disable();
+ pages_to_free = quicklist_size - max_pgt_pages();
}
preempt_enable();
}
@@ -521,7 +545,6 @@
mem_init (void)
{
long reserved_pages, codesize, datasize, initsize;
- unsigned long num_pgt_pages;
pg_data_t *pgdat;
int i;
static struct kcore_list kcore_mem, kcore_vmem, kcore_kernel;
@@ -563,19 +586,6 @@
reserved_pages << (PAGE_SHIFT - 10), datasize >> 10, initsize >>
10);
/*
- * Allow for enough (cached) page table pages so that we can map the
entire memory
- * at least once. Each task also needs a couple of page tables pages,
so add in a
- * fudge factor for that (don't use "threads-max" here; that would be
wrong!).
- * Don't allow the cache to be more than 10% of total memory, though.
- */
-# define NUM_TASKS 500 /* typical number of tasks */
- num_pgt_pages = nr_free_pages() / PTRS_PER_PGD + NUM_TASKS;
- if (num_pgt_pages > nr_free_pages() / 10)
- num_pgt_pages = nr_free_pages() / 10;
- if (num_pgt_pages > (u64) pgt_cache_water[1])
- pgt_cache_water[1] = num_pgt_pages;
-
- /*
* For fsyscall entrpoints with no light-weight handler, use the
ordinary
* (heavy-weight) handler, but mark it by setting bit 0, so the
fsyscall entry
* code can tell them apart.
-
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