[PATCH] VM instrumentation

A patch from Rik which adds some operational statitics to the VM.

In /proc/meminfo:

PageTables:	Amount of memory used for process pagetables
PteChainTot:	Amount of memory allocated for pte_chain objects
PteChainUsed:	Amount of memory currently in use for pte chains.

In /proc/stat:

pageallocs:	Number of pages allocated in the page allocator
pagefrees:	Number of pages returned to the page allocator

		(These can be used to measure the allocation rate)

pageactiv:	Number of pages activated (moved to the active list)
pagedeact:	Number of pages deactivated (moved to the inactive list)
pagefault:	Total pagefaults
majorfault:	Major pagefaults
pagescan:	Number of pages which shrink_cache looked at
pagesteal:	Number of pages which shrink_cache freed
pageoutrun:	Number of calls to try_to_free_pages()
allocstall:	Number of calls to balance_classzone()


Rik will be writing a userspace app which interprets these things.

The /proc/meminfo stats are efficient, but the /proc/stat accumulators
will cause undesirable cacheline bouncing.  We need to break the disk
statistics out of struct kernel_stat and make everything else in there
per-cpu.  If that doesn't happen in time for 2.6 then we disable
KERNEL_STAT_INC().

4 files changed, 19 insertions, 0 deletions

diff --git a/include/asm-arm/proc-armv/rmap.h b/include/asm-arm/proc-armv/rmap.h
index 0a9a9a55fb63..f775d26eea88 100644
--- a/include/asm-arm/proc-armv/rmap.h
+++ b/include/asm-arm/proc-armv/rmap.h
@@ -17,6 +17,7 @@ static inline void pgtable_add_rmap(pte_t * ptep, struct mm_struct * mm, unsigne
 
 	page->mm = mm;
 	page->index = address & ~((PTRS_PER_PTE * PAGE_SIZE) - 1);
+	inc_page_state(nr_page_table_pages);
 }
 
 static inline void pgtable_remove_rmap(pte_t * ptep)
@@ -25,6 +26,7 @@ static inline void pgtable_remove_rmap(pte_t * ptep)
 
 	page->mm = NULL;
 	page->index = 0;
+	dec_page_state(nr_page_table_pages);
 }
 
 static inline struct mm_struct * ptep_to_mm(pte_t * ptep)
diff --git a/include/asm-generic/rmap.h b/include/asm-generic/rmap.h
index 09ddf42f8638..c7045f3e6923 100644
--- a/include/asm-generic/rmap.h
+++ b/include/asm-generic/rmap.h
@@ -27,12 +27,14 @@ static inline void pgtable_add_rmap(struct page * page, struct mm_struct * mm, u
 #endif
 	page->mapping = (void *)mm;
 	page->index = address & ~((PTRS_PER_PTE * PAGE_SIZE) - 1);
+	inc_page_state(nr_page_table_pages);
 }
 
 static inline void pgtable_remove_rmap(struct page * page)
 {
 	page->mapping = NULL;
 	page->index = 0;
+	dec_page_state(nr_page_table_pages);
 }
 
 static inline struct mm_struct * ptep_to_mm(pte_t * ptep)
diff --git a/include/linux/kernel_stat.h b/include/linux/kernel_stat.h
index de592f2ba451..75533ee86b73 100644
--- a/include/linux/kernel_stat.h
+++ b/include/linux/kernel_stat.h
@@ -26,6 +26,11 @@ struct kernel_stat {
 	unsigned int dk_drive_wblk[DK_MAX_MAJOR][DK_MAX_DISK];
 	unsigned int pgpgin, pgpgout;
 	unsigned int pswpin, pswpout;
+	unsigned int pgalloc, pgfree;
+	unsigned int pgactivate, pgdeactivate;
+	unsigned int pgfault, pgmajfault;
+	unsigned int pgscan, pgsteal;
+	unsigned int pageoutrun, allocstall;
 #if !defined(CONFIG_ARCH_S390)
 	unsigned int irqs[NR_CPUS][NR_IRQS];
 #endif
@@ -35,6 +40,13 @@ extern struct kernel_stat kstat;
 
 extern unsigned long nr_context_switches(void);
 
+/*
+ * Maybe we need to smp-ify kernel_stat some day. It would be nice to do
+ * that without having to modify all the code that increments the stats.
+ */
+#define KERNEL_STAT_INC(x) kstat.x++
+#define KERNEL_STAT_ADD(x, y) kstat.x += y
+
 #if !defined(CONFIG_ARCH_S390)
 /*
  * Number of interrupts per specific IRQ source, since bootup
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index a1efdff4d23c..f272b7d7f465 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -78,6 +78,9 @@ extern struct page_state {
 	unsigned long nr_pagecache;
 	unsigned long nr_active;	/* on active_list LRU */
 	unsigned long nr_inactive;	/* on inactive_list LRU */
+	unsigned long nr_page_table_pages;
+	unsigned long nr_pte_chain_pages;
+	unsigned long used_pte_chains_bytes;
 } ____cacheline_aligned_in_smp page_states[NR_CPUS];
 
 extern void get_page_state(struct page_state *ret);