Re: Regression from 2.6.36

From: Andrew Morton
Date: Wed Apr 13 2011 - 17:25:43 EST


On Wed, 13 Apr 2011 14:16:00 -0700
Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:

> fs/file.c | 17 ++++++++++-------
> 1 file changed, 10 insertions(+), 7 deletions(-)

bah, stupid compiler.


--- a/fs/file.c~vfs-avoid-large-kmallocs-for-the-fdtable
+++ a/fs/file.c
@@ -9,6 +9,7 @@
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/mm.h>
+#include <linux/mmzone.h>
#include <linux/time.h>
#include <linux/sched.h>
#include <linux/slab.h>
@@ -39,14 +40,17 @@ int sysctl_nr_open_max = 1024 * 1024; /*
*/
static DEFINE_PER_CPU(struct fdtable_defer, fdtable_defer_list);

-static inline void *alloc_fdmem(unsigned int size)
+static void *alloc_fdmem(unsigned int size)
{
- void *data;
-
- data = kmalloc(size, GFP_KERNEL|__GFP_NOWARN);
- if (data != NULL)
- return data;
-
+ /*
+ * Very large allocations can stress page reclaim, so fall back to
+ * vmalloc() if the allocation size will be considered "large" by the VM.
+ */
+ if (size <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) {
+ void *data = kmalloc(size, GFP_KERNEL|__GFP_NOWARN);
+ if (data != NULL)
+ return data;
+ }
return vmalloc(size);
}

_

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