maps4: make page monitoring /proc file optional

Make /proc/ page monitoring configurable

This puts the following files under an embedded config option:

/proc/pid/clear_refs
/proc/pid/smaps
/proc/pid/pagemap
/proc/kpagecount
/proc/kpageflags

[akpm@linux-foundation.org: Kconfig fix]
Signed-off-by: Matt Mackall <mpm@selenic.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

5 files changed, 20 insertions, 3 deletions

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 9004db04efa0..cd9f84c4bbf5 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2249,7 +2249,7 @@ static const struct pid_entry tgid_base_stuff[] = {
         LNK("exe",        exe),
         REG("mounts",     S_IRUGO, mounts),
         REG("mountstats", S_IRUSR, mountstats),
-#ifdef CONFIG_MMU
+#ifdef CONFIG_PROC_PAGE_MONITOR
         REG("clear_refs", S_IWUSR, clear_refs),
         REG("smaps",      S_IRUGO, smaps),
         REG("pagemap",    S_IRUSR, pagemap),
@@ -2578,7 +2578,7 @@ static const struct pid_entry tid_base_stuff[] = {
         LNK("root",      root),
         LNK("exe",       exe),
         REG("mounts",    S_IRUGO, mounts),
-#ifdef CONFIG_MMU
+#ifdef CONFIG_PROC_PAGE_MONITOR
         REG("clear_refs", S_IWUSR, clear_refs),
         REG("smaps",     S_IRUGO, smaps),
         REG("pagemap",    S_IRUSR, pagemap),
diff --git a/fs/proc/proc_misc.c b/fs/proc/proc_misc.c
index fd751ea37fce..51288db37a0c 100644
--- a/fs/proc/proc_misc.c
+++ b/fs/proc/proc_misc.c
@@ -676,6 +676,7 @@ static const struct file_operations proc_sysrq_trigger_operations = {
 };
 #endif
 
+#ifdef CONFIG_PROC_PAGE_MONITOR
 #define KPMSIZE sizeof(u64)
 #define KPMMASK (KPMSIZE - 1)
 /* /proc/kpagecount - an array exposing page counts
@@ -804,6 +805,7 @@ static struct file_operations proc_kpageflags_operations = {
         .llseek = mem_lseek,
         .read = kpageflags_read,
 };
+#endif /* CONFIG_PROC_PAGE_MONITOR */
 
 struct proc_dir_entry *proc_root_kcore;
 
@@ -885,8 +887,10 @@ void __init proc_misc_init(void)
                                 (size_t)high_memory - PAGE_OFFSET + PAGE_SIZE;
         }
 #endif
+#ifdef CONFIG_PROC_PAGE_MONITOR
         create_seq_entry("kpagecount", S_IRUSR, &proc_kpagecount_operations);
         create_seq_entry("kpageflags", S_IRUSR, &proc_kpageflags_operations);
+#endif
 #ifdef CONFIG_PROC_VMCORE
         proc_vmcore = create_proc_entry("vmcore", S_IRUSR, NULL);
         if (proc_vmcore)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index bbd9b145051d..38338ed98cc6 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -337,6 +337,7 @@ const struct file_operations proc_maps_operations = {
  */
 #define PSS_SHIFT 12
 
+#ifdef CONFIG_PROC_PAGE_MONITOR
 struct mem_size_stats
 {
         struct vm_area_struct *vma;
@@ -717,6 +718,7 @@ const struct file_operations proc_pagemap_operations = {
         .llseek         = mem_lseek, /* borrow this */
         .read           = pagemap_read,
 };
+#endif /* CONFIG_PROC_PAGE_MONITOR */
 
 #ifdef CONFIG_NUMA
 extern int show_numa_map(struct seq_file *m, void *v);
diff --git a/init/Kconfig b/init/Kconfig
index dc28836d9d00..aaa7e7d5305e 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -678,6 +678,16 @@ config MARKERS
 
 source "arch/Kconfig"
 
+config PROC_PAGE_MONITOR
+        default y
+        depends on PROC_FS && MMU
+        bool "Enable /proc page monitoring" if EMBEDDED
+        help
+          Various /proc files exist to monitor process memory utilization:
+          /proc/pid/smaps, /proc/pid/clear_refs, /proc/pid/pagemap,
+          /proc/kpagecount, and /proc/kpageflags. Disabling these
+          interfaces will reduce the size of the kernel by approximately 4kb.
+
 endmenu         # General setup
 
 config SLABINFO
diff --git a/mm/Makefile b/mm/Makefile
index 07f12132f8e5..44e2528af70c 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -5,7 +5,7 @@
 mmu-y                   := nommu.o
 mmu-$(CONFIG_MMU)       := fremap.o highmem.o madvise.o memory.o mincore.o \
                            mlock.o mmap.o mprotect.o mremap.o msync.o rmap.o \
-                           vmalloc.o pagewalk.o
+                           vmalloc.o
 
 obj-y                   := bootmem.o filemap.o mempool.o oom_kill.o fadvise.o \
                            page_alloc.o page-writeback.o pdflush.o \
@@ -13,6 +13,7 @@ obj-y			:= bootmem.o filemap.o mempool.o oom_kill.o fadvise.o \
                            prio_tree.o util.o mmzone.o vmstat.o backing-dev.o \
                            page_isolation.o $(mmu-y)
 
+obj-$(CONFIG_PROC_PAGE_MONITOR) += pagewalk.o
 obj-$(CONFIG_BOUNCE)    += bounce.o
 obj-$(CONFIG_SWAP)      += page_io.o swap_state.o swapfile.o thrash.o
 obj-$(CONFIG_HUGETLBFS) += hugetlb.o