RE: HUGEPAGE SIZE a boottime option

["Chen, Kenneth W" <kenneth.w.chen@intel.com>]

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We believe we have resolved all the remain issues, all critical
speed path has been taken care of, i.e., vhpt hander and context
switch.  There should be no performance penalty with this dynamic
hugetlb page size feature.

David, this is our final tested patch.

- Ken

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diff -Nurp linux-2.6.3/arch/ia64/Kconfig linux-2.6.3.htlb/arch/ia64/Kconfig
--- linux-2.6.3/arch/ia64/Kconfig	2004-02-25 17:17:57.000000000 -0800
+++ linux-2.6.3.htlb/arch/ia64/Kconfig	2004-02-25 17:19:05.000000000 -0800
@@ -282,39 +282,6 @@ config FORCE_MAX_ZONEORDER
 	int
 	default "18"
 
-choice
-	prompt "Huge TLB page size"
-	depends on HUGETLB_PAGE
-	default HUGETLB_PAGE_SIZE_16MB
-
-config HUGETLB_PAGE_SIZE_4GB
-	depends on MCKINLEY
-	bool "4GB"
-
-config HUGETLB_PAGE_SIZE_1GB
-	depends on MCKINLEY
-	bool "1GB"
-
-config HUGETLB_PAGE_SIZE_256MB
-	bool "256MB"
-
-config HUGETLB_PAGE_SIZE_64MB
-	bool "64MB"
-
-config HUGETLB_PAGE_SIZE_16MB
-	bool "16MB"
-
-config HUGETLB_PAGE_SIZE_4MB
-	bool "4MB"
-
-config HUGETLB_PAGE_SIZE_1MB
-	bool "1MB"
-
-config HUGETLB_PAGE_SIZE_256KB
-	bool "256KB"
-
-endchoice
-
 config IA64_PAL_IDLE
 	bool "Use PAL_HALT_LIGHT in idle loop"
 	help
diff -Nurp linux-2.6.3/arch/ia64/kernel/ivt.S linux-2.6.3.htlb/arch/ia64/kernel/ivt.S
--- linux-2.6.3/arch/ia64/kernel/ivt.S	2004-02-25 17:17:57.000000000 -0800
+++ linux-2.6.3.htlb/arch/ia64/kernel/ivt.S	2004-02-25 17:19:05.000000000 -0800
@@ -118,10 +118,11 @@ ENTRY(vhpt_miss)
 #ifdef CONFIG_HUGETLB_PAGE
 	extr.u r26=r25,2,6
 	;;
-	cmp.eq p8,p0=HPAGE_SHIFT,r26
+	cmp.ne p8,p0=r18,r26
+	sub r27=r26,r18
 	;;
 (p8)	dep r25=r18,r25,2,6
-(p8)	shr r22=r22,HPAGE_SHIFT-PAGE_SHIFT
+(p8)	shr r22=r22,r27
 #endif
 	;;
 	cmp.eq p6,p7=5,r17			// is IFA pointing into to region 5?
diff -Nurp linux-2.6.3/arch/ia64/mm/hugetlbpage.c linux-2.6.3.htlb/arch/ia64/mm/hugetlbpage.c
--- linux-2.6.3/arch/ia64/mm/hugetlbpage.c	2004-02-25 17:17:57.000000000 -0800
+++ linux-2.6.3.htlb/arch/ia64/mm/hugetlbpage.c	2004-02-25 17:19:05.000000000 -0800
@@ -1,7 +1,11 @@
 /*
  * IA-64 Huge TLB Page Support for Kernel.
  *
- * Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
+ * Copyright (C) 2002-2004 Rohit Seth <rohit.seth@intel.com>
+ * Copyright (C) 2003-2004 Ken Chen <kenneth.w.chen@intel.com>
+ *
+ * Sep, 2003: add numa support
+ * Feb, 2004: dynamic hugetlb page size via command line
  */
 
 #include <linux/config.h>
@@ -23,6 +27,7 @@
 static long	htlbpagemem;
 int		htlbpage_max;
 static long	htlbzone_pages;
+unsigned int	hpage_shift=HPAGE_SHIFT_DEFAULT;
 
 static struct list_head hugepage_freelists[MAX_NUMNODES];
 static spinlock_t htlbpage_lock = SPIN_LOCK_UNLOCKED;
@@ -520,6 +525,35 @@ static int __init hugetlb_setup(char *s)
 }
 __setup("hugepages=", hugetlb_setup);
 
+static int __init hugetlb_setup_sz(char *str)
+{
+	u64 tr_pages;
+	unsigned long long size;
+
+	if (ia64_pal_vm_page_size(&tr_pages, NULL) != 0)
+		/*
+		 * shouldn't happen, but just in case.
+		 */
+		tr_pages = 0x15557000UL;
+
+	size = memparse(str, &str);
+	if (*str || (size & (size-1)) || !(tr_pages & size) ||
+		size <= PAGE_SIZE ||
+		size >= (1UL << PAGE_SHIFT << MAX_ORDER)) {
+		printk(KERN_WARNING "Invalid huge page size specified\n");
+		return 1;
+	}
+
+	hpage_shift = __ffs(size);
+	/*
+	 * boot cpu already executed ia64_mmu_init, and has HPAGE_SHIFT_DEFAULT
+	 * override here with new page shift.
+	 */
+	ia64_set_rr(0x8000000000000000, hpage_shift << 2);
+	return 1;
+}
+__setup("hugepagesz=", hugetlb_setup_sz);
+
 static int __init hugetlb_init(void)
 {
 	int i;
@@ -540,7 +574,7 @@ static int __init hugetlb_init(void)
 	printk("Total HugeTLB memory allocated, %ld\n", htlbpagemem);
 	return 0;
 }
-module_init(hugetlb_init);
+__initcall(hugetlb_init);
 
 int hugetlb_report_meminfo(char *buf)
 {
diff -Nurp linux-2.6.3/arch/ia64/mm/init.c linux-2.6.3.htlb/arch/ia64/mm/init.c
--- linux-2.6.3/arch/ia64/mm/init.c	2004-02-25 17:17:57.000000000 -0800
+++ linux-2.6.3.htlb/arch/ia64/mm/init.c	2004-02-25 17:19:05.000000000 -0800
@@ -342,6 +342,10 @@ ia64_mmu_init (void *my_cpu_data)
 
 	ia64_tlb_init();
 
+#ifdef	CONFIG_HUGETLB_PAGE
+	ia64_set_rr(0x8000000000000000, hpage_shift << 2);
+#endif
+
 #ifdef	CONFIG_IA64_MCA
 	cpu = smp_processor_id();
 
diff -Nurp linux-2.6.3/include/asm-ia64/mmu_context.h linux-2.6.3.htlb/include/asm-ia64/mmu_context.h
--- linux-2.6.3/include/asm-ia64/mmu_context.h	2004-02-25 17:18:04.000000000 -0800
+++ linux-2.6.3.htlb/include/asm-ia64/mmu_context.h	2004-02-25 17:19:05.000000000 -0800
@@ -140,8 +140,9 @@ reload_context (mm_context_t context)
 {
 	unsigned long rid;
 	unsigned long rid_incr = 0;
-	unsigned long rr0, rr1, rr2, rr3, rr4;
+	unsigned long rr0, rr1, rr2, rr3, rr4, old_rr4;
 
+	old_rr4 = ia64_get_rr(0x8000000000000000);
 	rid = context << 3;	/* make space for encoding the region number */
 	rid_incr = 1 << 8;
 
@@ -152,7 +153,7 @@ reload_context (mm_context_t context)
 	rr3 = rr0 + 3*rid_incr;
 	rr4 = rr0 + 4*rid_incr;
 #ifdef  CONFIG_HUGETLB_PAGE
-	rr4 = (rr4 & (~(0xfcUL))) | (HPAGE_SHIFT << 2);
+	rr4 = (rr4 & (~(0xfcUL))) | (old_rr4 & 0xfc);
 #endif
 
 	ia64_set_rr(0x0000000000000000, rr0);
diff -Nurp linux-2.6.3/include/asm-ia64/page.h linux-2.6.3.htlb/include/asm-ia64/page.h
--- linux-2.6.3/include/asm-ia64/page.h	2004-02-25 17:18:04.000000000 -0800
+++ linux-2.6.3.htlb/include/asm-ia64/page.h	2004-02-25 17:19:05.000000000 -0800
@@ -37,27 +37,8 @@
 #define RGN_MAP_LIMIT	((1UL << (4*PAGE_SHIFT - 12)) - PAGE_SIZE)	/* per region addr limit */
 
 #ifdef CONFIG_HUGETLB_PAGE
-
-# if defined(CONFIG_HUGETLB_PAGE_SIZE_4GB)
-#  define HPAGE_SHIFT	32
-# elif defined(CONFIG_HUGETLB_PAGE_SIZE_1GB)
-#  define HPAGE_SHIFT	30
-# elif defined(CONFIG_HUGETLB_PAGE_SIZE_256MB)
-#  define HPAGE_SHIFT	28
-# elif defined(CONFIG_HUGETLB_PAGE_SIZE_64MB)
-#  define HPAGE_SHIFT	26
-# elif defined(CONFIG_HUGETLB_PAGE_SIZE_16MB)
-#  define HPAGE_SHIFT	24
-# elif defined(CONFIG_HUGETLB_PAGE_SIZE_4MB)
-#  define HPAGE_SHIFT	22
-# elif defined(CONFIG_HUGETLB_PAGE_SIZE_1MB)
-#  define HPAGE_SHIFT	20
-# elif defined(CONFIG_HUGETLB_PAGE_SIZE_256KB)
-#  define HPAGE_SHIFT	18
-# else
-#  error Unsupported IA-64 HugeTLB Page Size!
-# endif
-
+# define HPAGE_SHIFT hpage_shift
+# define HPAGE_SHIFT_DEFAULT	28	/* check ia64 SDM for architecture supported size */
 # define REGION_HPAGE	(4UL)	/* note: this is hardcoded in mmu_context.h:reload_context()!*/
 # define REGION_SHIFT	61
 # define HPAGE_SIZE	(__IA64_UL_CONST(1) << HPAGE_SHIFT)
@@ -140,6 +121,7 @@ typedef union ia64_va {
 # define is_hugepage_only_range(addr, len)		\
 	 (REGION_NUMBER(addr) == REGION_HPAGE &&	\
 	  REGION_NUMBER((addr)+(len)) == REGION_HPAGE)
+extern unsigned int hpage_shift;
 #endif
 
 static __inline__ int