[PATCH 1/1] powerpc: Update page in counter for CMM

[Brian King]

A new field has been added to the VPA as a method for
the client OS to communicate to firmware the number of
page ins it is performing when running collaborative
memory overcommit. The hypervisor will use this information
to better determine if a partition is experiencing memory
pressure and needs more memory allocated to it.

Signed-off-by: Brian King <brking at linux.vnet.ibm.com>
---

 arch/powerpc/include/asm/lppaca.h |    3 ++-
 arch/powerpc/kernel/paca.c        |    1 +
 arch/powerpc/mm/fault.c           |    8 ++++++--
 3 files changed, 9 insertions(+), 3 deletions(-)

diff -puN arch/powerpc/mm/fault.c~powerpc_vrm_mm_pressure arch/powerpc/mm/fault.c
--- linux-2.6/arch/powerpc/mm/fault.c~powerpc_vrm_mm_pressure	2008-10-20 17:13:25.000000000 -0500
+++ linux-2.6-bjking1/arch/powerpc/mm/fault.c	2008-10-20 17:13:25.000000000 -0500
@@ -30,6 +30,8 @@
 #include <linux/kprobes.h>
 #include <linux/kdebug.h>
 
+#include <asm/atomic.h>
+#include <asm/firmware.h>
 #include <asm/page.h>
 #include <asm/pgtable.h>
 #include <asm/mmu.h>
@@ -318,9 +320,11 @@ good_area:
 			goto do_sigbus;
 		BUG();
 	}
-	if (ret & VM_FAULT_MAJOR)
+	if (ret & VM_FAULT_MAJOR) {
 		current->maj_flt++;
-	else
+		if (firmware_has_feature(FW_FEATURE_CMO))
+			atomic_inc((atomic_t *)(&(get_lppaca()->page_ins)));
+	} else
 		current->min_flt++;
 	up_read(&mm->mmap_sem);
 	return 0;
diff -puN arch/powerpc/include/asm/lppaca.h~powerpc_vrm_mm_pressure arch/powerpc/include/asm/lppaca.h
--- linux-2.6/arch/powerpc/include/asm/lppaca.h~powerpc_vrm_mm_pressure	2008-10-20 17:13:25.000000000 -0500
+++ linux-2.6-bjking1/arch/powerpc/include/asm/lppaca.h	2008-10-20 17:13:25.000000000 -0500
@@ -133,7 +133,8 @@ struct lppaca {
 //=============================================================================
 // CACHE_LINE_4-5 0x0180 - 0x027F Contains PMC interrupt data
 //=============================================================================
-	u8	pmc_save_area[256];	// PMC interrupt Area           x00-xFF
+	volatile u32 page_ins;		// CMO Hint - # page ins by OS  x00-x04
+	u8	pmc_save_area[252];	// PMC interrupt Area           x04-xFF
 } __attribute__((__aligned__(0x400)));
 
 extern struct lppaca lppaca[];
diff -puN arch/powerpc/kernel/paca.c~powerpc_vrm_mm_pressure arch/powerpc/kernel/paca.c
--- linux-2.6/arch/powerpc/kernel/paca.c~powerpc_vrm_mm_pressure	2008-10-20 17:13:25.000000000 -0500
+++ linux-2.6-bjking1/arch/powerpc/kernel/paca.c	2008-10-20 17:13:25.000000000 -0500
@@ -37,6 +37,7 @@ struct lppaca lppaca[] = {
 		.end_of_quantum = 0xfffffffffffffffful,
 		.slb_count = 64,
 		.vmxregs_in_use = 0,
+		.page_ins = 0,
 	},
 };
 
_