Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/mm/memory.c | 7 +++++++
1 files changed, 7 insertions(+)
diff -puN mm/memory.c~get_user_pages-latency-fix mm/memory.c
--- 25/mm/memory.c~get_user_pages-latency-fix 2004-07-13 15:49:55.657522560 -0700
+++ 25-akpm/mm/memory.c 2004-07-13 15:51:47.694490352 -0700
@@ -710,6 +710,7 @@ int get_user_pages(struct task_struct *t
int i;
int vm_io;
unsigned int flags;
+ int nr_pages = 0;
/*
* Require read or write permissions.
@@ -773,6 +774,12 @@ int get_user_pages(struct task_struct *t
struct page *map = NULL;
int lookup_write = write;
+ if ((++nr_pages & 63) == 0) {
+ spin_unlock(&mm->page_table_lock);
+ cpu_relax();
+ spin_lock(&mm->page_table_lock);
+ }
+
/*
* We don't follow pagetables for VM_IO regions - they
* may have no pageframes.
_