From: Paul Szabo <psz@maths.usyd.edu.au>
Date: Sat, 23 Feb 2013 00:34:42 +0000 (-0800)
Subject: page-writeback.c: subtract min_free_kbytes from dirtyable memory
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=75f7ad8e043d;p=linux-beck.git

page-writeback.c: subtract min_free_kbytes from dirtyable memory

When calculating amount of dirtyable memory, min_free_kbytes should be
subtracted because it is not intended for dirty pages.

Addresses http://bugs.debian.org/695182

[akpm@linux-foundation.org: fix up min_free_kbytes extern declarations]
[akpm@linux-foundation.org: fix min() warning]
Signed-off-by: Paul Szabo <psz@maths.usyd.edu.au>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 1d4122bf6f27..437da0ce78c7 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1393,6 +1393,9 @@ extern void setup_per_cpu_pageset(void);
 extern void zone_pcp_update(struct zone *zone);
 extern void zone_pcp_reset(struct zone *zone);
 
+/* page_alloc.c */
+extern int min_free_kbytes;
+
 /* nommu.c */
 extern atomic_long_t mmap_pages_allocated;
 extern int nommu_shrink_inode_mappings(struct inode *, size_t, size_t);
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 467d8b923fcd..95e9e55602a8 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -105,7 +105,6 @@ extern char core_pattern[];
 extern unsigned int core_pipe_limit;
 #endif
 extern int pid_max;
-extern int min_free_kbytes;
 extern int pid_max_min, pid_max_max;
 extern int sysctl_drop_caches;
 extern int percpu_pagelist_fraction;
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index b1cc6591ed83..c63a21d0e991 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -105,7 +105,6 @@ static int set_recommended_min_free_kbytes(void)
 	struct zone *zone;
 	int nr_zones = 0;
 	unsigned long recommended_min;
-	extern int min_free_kbytes;
 
 	if (!khugepaged_enabled())
 		return 0;
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 7300c9d5e1d9..cdc377c456c0 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -241,6 +241,9 @@ static unsigned long global_dirtyable_memory(void)
 	if (!vm_highmem_is_dirtyable)
 		x -= highmem_dirtyable_memory(x);
 
+	/* Subtract min_free_kbytes */
+	x -= min_t(unsigned long, x, min_free_kbytes >> (PAGE_SHIFT - 10));
+
 	return x + 1;	/* Ensure that we never return 0 */
 }