[patch] sched, mm: fix scheduling latencies in filemap_sync()

Ingo Molnar
2004-09-14T11:07:30Z

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The attached patch, written by Andrew Morton, fixes long scheduling
latencies in filemap_sync().

has been tested as part of the -VP patchset.

Ingo

[-- Attachment #2: fix-latency-filemap_sync.patch --]
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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>

--- linux/mm/msync.c.orig
+++ linux/mm/msync.c
@@ -92,8 +92,8 @@ static inline int filemap_sync_pmd_range
return error;
}

-static int filemap_sync(struct vm_area_struct * vma, unsigned long address,
- size_t size, unsigned int flags)
+static int __filemap_sync(struct vm_area_struct *vma, unsigned long address,
+ size_t size, unsigned int flags)
{
pgd_t * dir;
unsigned long end = address + size;
@@ -131,6 +131,31 @@ 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.
*