linux-kernel - [RPC][PATCH 2.6.20-rc5] limit total vfs page cache

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Date:	Thu, 18 Jan 2007 11:23:23 +0800
From:	"Aubrey Li" <aubreylee@...il.com>
To:	linux-kernel@...r.kernel.org, linux-mm@...ck.org
Cc:	"Linus Torvalds" <torvalds@...l.org>,
	"Andrew Morton" <akpm@...l.org>,
	"Nick Piggin" <nickpiggin@...oo.com.au>,
	"linux-os (Dick Johnson)" <linux-os@...logic.com>,
	"Robin Getz" <rgetz@...ckfin.uclinux.org>
Subject: [RPC][PATCH 2.6.20-rc5] limit total vfs page cache

Here is the newest patch against 2.6.20-rc5.
======================================================
>From ad9ca9a32bdcaddce9988afbf0187bfd04685a0c Mon Sep 17 00:00:00 2001
From: Aubrey.Li <aubreylee@...il.com>
Date: Thu, 18 Jan 2007 11:08:31 +0800
Subject: [PATCH] Add an interface to limit total vfs page cache.
The default percent is using 90% memory for page cache.

Signed-off-by: Aubrey.Li <aubreylee@...il.com>
---
 include/linux/gfp.h     |    1 +
 include/linux/pagemap.h |    2 +-
 include/linux/sysctl.h  |    2 ++
 kernel/sysctl.c         |   11 +++++++++++
 mm/page_alloc.c         |   17 +++++++++++++++--
 5 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index 00c314a..531360e 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -46,6 +46,7 @@ struct vm_area_struct;
 #define __GFP_NOMEMALLOC ((__force gfp_t)0x10000u) /* Don't use
emergency reserves */
 #define __GFP_HARDWALL   ((__force gfp_t)0x20000u) /* Enforce
hardwall cpuset memory allocs */
 #define __GFP_THISNODE	((__force gfp_t)0x40000u)/* No fallback, no policies */
+#define __GFP_PAGECACHE	((__force gfp_t)0x80000u) /* Is page cache
allocation ? */

 #define __GFP_BITS_SHIFT 20	/* Room for 20 __GFP_FOO bits */
 #define __GFP_BITS_MASK ((__force gfp_t)((1 << __GFP_BITS_SHIFT) - 1))
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index c3e255b..890bb23 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -62,7 +62,7 @@ static inline struct page *__page_cache_

 static inline struct page *page_cache_alloc(struct address_space *x)
 {
-	return __page_cache_alloc(mapping_gfp_mask(x));
+	return __page_cache_alloc(mapping_gfp_mask(x)|__GFP_PAGECACHE);
 }

 static inline struct page *page_cache_alloc_cold(struct address_space *x)
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 81480e6..d3c9174 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -202,6 +202,7 @@ enum
 	VM_PANIC_ON_OOM=33,	/* panic at out-of-memory */
 	VM_VDSO_ENABLED=34,	/* map VDSO into new processes? */
 	VM_MIN_SLAB=35,		 /* Percent pages ignored by zone reclaim */
+	VM_PAGECACHE_RATIO=36,	/* percent of RAM to use as page cache */
 };


@@ -955,6 +956,7 @@ extern ctl_handler sysctl_string;
 extern ctl_handler sysctl_intvec;
 extern ctl_handler sysctl_jiffies;
 extern ctl_handler sysctl_ms_jiffies;
+extern int sysctl_pagecache_ratio;


 /*
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 600b333..92db115 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1035,6 +1035,17 @@ static ctl_table vm_table[] = {
 		.extra1		= &zero,
 	},
 #endif
+	{
+		.ctl_name	= VM_PAGECACHE_RATIO,
+		.procname	= "pagecache_ratio",
+		.data		= &sysctl_pagecache_ratio,
+		.maxlen		= sizeof(sysctl_pagecache_ratio),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec_minmax,
+		.strategy	= &sysctl_intvec,
+		.extra1         = &zero,
+                .extra2         = &one_hundred,
+	},
 	{ .ctl_name = 0 }
 };

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index fc5b544..5802b39 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -82,6 +82,8 @@ int sysctl_lowmem_reserve_ratio[MAX_NR_Z
 #endif
 };

+int sysctl_pagecache_ratio = 10;
+
 EXPORT_SYMBOL(totalram_pages);

 static char * const zone_names[MAX_NR_ZONES] = {
@@ -895,6 +897,7 @@ failed:
 #define ALLOC_HARDER		0x10 /* try to alloc harder */
 #define ALLOC_HIGH		0x20 /* __GFP_HIGH set */
 #define ALLOC_CPUSET		0x40 /* check for correct cpuset */
+#define ALLOC_PAGECACHE		0x80 /* __GFP_PAGECACHE set */

 #ifdef CONFIG_FAIL_PAGE_ALLOC

@@ -998,6 +1001,9 @@ int zone_watermark_ok(struct zone *z, in
 	if (alloc_flags & ALLOC_HARDER)
 		min -= min / 4;

+	if (alloc_flags & ALLOC_PAGECACHE)
+		min = min + (sysctl_pagecache_ratio * z->present_pages) / 100;
+
 	if (free_pages <= min + z->lowmem_reserve[classzone_idx])
 		return 0;
 	for (o = 0; o < order; o++) {
@@ -1236,8 +1242,12 @@ restart:
 		return NULL;
 	}

-	page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, order,
-				zonelist, ALLOC_WMARK_LOW|ALLOC_CPUSET);
+	if (gfp_mask & __GFP_PAGECACHE)	
+		page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, order,
+			zonelist, ALLOC_WMARK_LOW|ALLOC_CPUSET|ALLOC_PAGECACHE);
+	else
+		page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, order,
+					zonelist, ALLOC_WMARK_LOW|ALLOC_CPUSET);
 	if (page)
 		goto got_pg;

@@ -1273,6 +1283,9 @@ restart:
 	if (wait)
 		alloc_flags |= ALLOC_CPUSET;

+	if (gfp_mask & __GFP_PAGECACHE)
+		alloc_flags |= ALLOC_PAGECACHE;
+
 	/*
 	 * Go through the zonelist again. Let __GFP_HIGH and allocations
 	 * coming from realtime tasks go deeper into reserves.
-- 
1.4.3.4
=====================================================

View attachment "0001-Add-an-interface-to-limit-total-vfs-page-cache.txt" of type "text/plain" (4593 bytes)