From: Ingo Molnar <mingo@elte.hu>
The attached patch, written by Andrew Morton, fixes long scheduling
latencies in filemap_sync().
Has been tested as part of the -VP patchset.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/mm/msync.c | 27 ++++++++++++++++++++++++++-
1 files changed, 26 insertions(+), 1 deletion(-)
diff -puN mm/msync.c~sched-mm-fix-scheduling-latencies-in-filemap_sync mm/msync.c
--- 25/mm/msync.c~sched-mm-fix-scheduling-latencies-in-filemap_sync Fri Nov 5 16:06:40 2004
+++ 25-akpm/mm/msync.c Fri Nov 5 16:07:10 2004
@@ -115,7 +115,7 @@ static inline int filemap_sync_pgd_range
return error;
}
-static int filemap_sync(struct vm_area_struct *vma, unsigned long address,
+static int __filemap_sync(struct vm_area_struct *vma, unsigned long address,
size_t size, unsigned int flags)
{
pml4_t *pml4;
@@ -159,6 +159,31 @@ static int filemap_sync(struct vm_area_s
return error;
}
+#ifdef CONFIG_PREEMPT
+static int filemap_sync(struct vm_area_struct *vma, unsigned long address,
+ size_t size, unsigned int flags)
+{
+ const size_t chunk = 64 * 1024; /* bytes */
+ int error = 0;
+
+ while (size) {
+ size_t sz = min(size, chunk);
+
+ error |= __filemap_sync(vma, address, sz, flags);
+ cond_resched();
+ address += sz;
+ size -= sz;
+ }
+ return error;
+}
+#else
+static int filemap_sync(struct vm_area_struct *vma, unsigned long address,
+ size_t size, unsigned int flags)
+{
+ return __filemap_sync(vma, address, size, flags);
+}
+#endif
+
/*
* MS_SYNC syncs the entire file - including mappings.
*
_