[2/2] mm: rename global_page_state to global_zone_page_state
diff mbox series

Message ID 20170801134256.5400-2-hannes@cmpxchg.org
State New, archived
Headers show
Series
  • [1/2] mm: fix global NR_SLAB_.*CLAIMABLE counter reads
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Commit Message

Johannes Weiner Aug. 1, 2017, 1:42 p.m. UTC
From: Michal Hocko <mhocko@suse.com>

global_page_state is error prone as a recent bug report pointed out [1].
It only returns proper values for zone based counters as the enum it
gets suggests. We already have global_node_page_state so let's rename
global_page_state to global_zone_page_state to be more explicit here.
All existing users seems to be correct
$ git grep "global_page_state(NR_" | sed 's@.*(\(NR_[A-Z_]*\)).*@\1@' | sort | uniq -c
      2 NR_BOUNCE
      2 NR_FREE_CMA_PAGES
     11 NR_FREE_PAGES
      1 NR_KERNEL_STACK_KB
      1 NR_MLOCK
      2 NR_PAGETABLE

This patch shouldn't introduce any functional change.

[1] http://lkml.kernel.org/r/201707260628.v6Q6SmaS030814@www262.sakura.ne.jp

Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
---
 fs/proc/meminfo.c      | 10 +++++-----
 include/linux/swap.h   |  4 ++--
 include/linux/vmstat.h |  4 ++--
 mm/mmap.c              |  6 +++---
 mm/nommu.c             |  4 ++--
 mm/page-writeback.c    |  4 ++--
 mm/page_alloc.c        | 12 ++++++------
 mm/util.c              |  2 +-
 mm/vmstat.c            |  4 ++--
 9 files changed, 25 insertions(+), 25 deletions(-)

Comments

Andrew Morton Aug. 1, 2017, 9:05 p.m. UTC | #1
On Tue,  1 Aug 2017 09:42:56 -0400 Johannes Weiner <hannes@cmpxchg.org> wrote:

> global_page_state is error prone as a recent bug report pointed out [1].
> It only returns proper values for zone based counters as the enum it
> gets suggests. We already have global_node_page_state so let's rename
> global_page_state to global_zone_page_state to be more explicit here.
> All existing users seems to be correct
> $ git grep "global_page_state(NR_" | sed 's@.*(\(NR_[A-Z_]*\)).*@\1@' | sort | uniq -c
>       2 NR_BOUNCE
>       2 NR_FREE_CMA_PAGES
>      11 NR_FREE_PAGES
>       1 NR_KERNEL_STACK_KB
>       1 NR_MLOCK
>       2 NR_PAGETABLE
> 
> This patch shouldn't introduce any functional change.

Checkpatch gets a bit whiny.


WARNING: line over 80 characters
#127: FILE: mm/mmap.c:3517:
+	free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);

WARNING: line over 80 characters
#136: FILE: mm/mmap.c:3538:
+	free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);

WARNING: line over 80 characters
#145: FILE: mm/mmap.c:3582:
+		free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);

WARNING: line over 80 characters
#157: FILE: mm/nommu.c:1965:
+	free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);

WARNING: line over 80 characters
#166: FILE: mm/nommu.c:1986:
+	free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);

WARNING: line over 80 characters
#187: FILE: mm/page-writeback.c:1408:
+ * global_zone_page_state() too often. So scale it near-sqrt to the safety margin


Liveable with, but the code would be quite a bit neater if we had a
helper function for this.  We get things like:

--- a/mm/mmap.c~mm-rename-global_page_state-to-global_zone_page_state-fix
+++ a/mm/mmap.c
@@ -3512,11 +3512,7 @@ void __init mmap_init(void)
  */
 static int init_user_reserve(void)
 {
-	unsigned long free_kbytes;
-
-	free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
-
-	sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17);
+	sysctl_user_reserve_kbytes = min(global_free_kbytes() / 32, 1UL << 17);
 	return 0;
 }
 subsys_initcall(init_user_reserve);
Michal Hocko Aug. 2, 2017, 7:42 a.m. UTC | #2
On Tue 01-08-17 14:05:20, Andrew Morton wrote:
[...]
> WARNING: line over 80 characters
> #187: FILE: mm/page-writeback.c:1408:
> + * global_zone_page_state() too often. So scale it near-sqrt to the safety margin
> 
> 
> Liveable with, but the code would be quite a bit neater if we had a
> helper function for this.

I vaguely remember somebody wanted to add/consolidate a helper to
convert pages to kB as we have more of those. I wouldn't lose
sleep over "line over 80 characters" warnings in this case. Those lines
are still readable.

Patch
diff mbox series

diff --git a/fs/proc/meminfo.c b/fs/proc/meminfo.c
index 509a61668d90..cdd979724c74 100644
--- a/fs/proc/meminfo.c
+++ b/fs/proc/meminfo.c
@@ -80,7 +80,7 @@  static int meminfo_proc_show(struct seq_file *m, void *v)
 	show_val_kb(m, "Active(file):   ", pages[LRU_ACTIVE_FILE]);
 	show_val_kb(m, "Inactive(file): ", pages[LRU_INACTIVE_FILE]);
 	show_val_kb(m, "Unevictable:    ", pages[LRU_UNEVICTABLE]);
-	show_val_kb(m, "Mlocked:        ", global_page_state(NR_MLOCK));
+	show_val_kb(m, "Mlocked:        ", global_zone_page_state(NR_MLOCK));
 
 #ifdef CONFIG_HIGHMEM
 	show_val_kb(m, "HighTotal:      ", i.totalhigh);
@@ -114,9 +114,9 @@  static int meminfo_proc_show(struct seq_file *m, void *v)
 	show_val_kb(m, "SUnreclaim:     ",
 		    global_node_page_state(NR_SLAB_UNRECLAIMABLE));
 	seq_printf(m, "KernelStack:    %8lu kB\n",
-		   global_page_state(NR_KERNEL_STACK_KB));
+		   global_zone_page_state(NR_KERNEL_STACK_KB));
 	show_val_kb(m, "PageTables:     ",
-		    global_page_state(NR_PAGETABLE));
+		    global_zone_page_state(NR_PAGETABLE));
 #ifdef CONFIG_QUICKLIST
 	show_val_kb(m, "Quicklists:     ", quicklist_total_size());
 #endif
@@ -124,7 +124,7 @@  static int meminfo_proc_show(struct seq_file *m, void *v)
 	show_val_kb(m, "NFS_Unstable:   ",
 		    global_node_page_state(NR_UNSTABLE_NFS));
 	show_val_kb(m, "Bounce:         ",
-		    global_page_state(NR_BOUNCE));
+		    global_zone_page_state(NR_BOUNCE));
 	show_val_kb(m, "WritebackTmp:   ",
 		    global_node_page_state(NR_WRITEBACK_TEMP));
 	show_val_kb(m, "CommitLimit:    ", vm_commit_limit());
@@ -151,7 +151,7 @@  static int meminfo_proc_show(struct seq_file *m, void *v)
 #ifdef CONFIG_CMA
 	show_val_kb(m, "CmaTotal:       ", totalcma_pages);
 	show_val_kb(m, "CmaFree:        ",
-		    global_page_state(NR_FREE_CMA_PAGES));
+		    global_zone_page_state(NR_FREE_CMA_PAGES));
 #endif
 
 	hugetlb_report_meminfo(m);
diff --git a/include/linux/swap.h b/include/linux/swap.h
index d83d28e53e62..bf49b79218f4 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -262,8 +262,8 @@  extern unsigned long totalreserve_pages;
 extern unsigned long nr_free_buffer_pages(void);
 extern unsigned long nr_free_pagecache_pages(void);
 
-/* Definition of global_page_state not available yet */
-#define nr_free_pages() global_page_state(NR_FREE_PAGES)
+/* Definition of global_zone_page_state not available yet */
+#define nr_free_pages() global_zone_page_state(NR_FREE_PAGES)
 
 
 /* linux/mm/swap.c */
diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
index b3d85f30d424..97e11ab573f0 100644
--- a/include/linux/vmstat.h
+++ b/include/linux/vmstat.h
@@ -123,7 +123,7 @@  static inline void node_page_state_add(long x, struct pglist_data *pgdat,
 	atomic_long_add(x, &vm_node_stat[item]);
 }
 
-static inline unsigned long global_page_state(enum zone_stat_item item)
+static inline unsigned long global_zone_page_state(enum zone_stat_item item)
 {
 	long x = atomic_long_read(&vm_zone_stat[item]);
 #ifdef CONFIG_SMP
@@ -199,7 +199,7 @@  extern unsigned long sum_zone_node_page_state(int node,
 extern unsigned long node_page_state(struct pglist_data *pgdat,
 						enum node_stat_item item);
 #else
-#define sum_zone_node_page_state(node, item) global_page_state(item)
+#define sum_zone_node_page_state(node, item) global_zone_page_state(item)
 #define node_page_state(node, item) global_node_page_state(item)
 #endif /* CONFIG_NUMA */
 
diff --git a/mm/mmap.c b/mm/mmap.c
index f19efcf75418..9800e29763f4 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -3514,7 +3514,7 @@  static int init_user_reserve(void)
 {
 	unsigned long free_kbytes;
 
-	free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
+	free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
 
 	sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17);
 	return 0;
@@ -3535,7 +3535,7 @@  static int init_admin_reserve(void)
 {
 	unsigned long free_kbytes;
 
-	free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
+	free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
 
 	sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13);
 	return 0;
@@ -3579,7 +3579,7 @@  static int reserve_mem_notifier(struct notifier_block *nb,
 
 		break;
 	case MEM_OFFLINE:
-		free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
+		free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
 
 		if (sysctl_user_reserve_kbytes > free_kbytes) {
 			init_user_reserve();
diff --git a/mm/nommu.c b/mm/nommu.c
index fc184f597d59..53d5175a5c14 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1962,7 +1962,7 @@  static int __meminit init_user_reserve(void)
 {
 	unsigned long free_kbytes;
 
-	free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
+	free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
 
 	sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17);
 	return 0;
@@ -1983,7 +1983,7 @@  static int __meminit init_admin_reserve(void)
 {
 	unsigned long free_kbytes;
 
-	free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
+	free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
 
 	sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13);
 	return 0;
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 96e93b214d31..88562a0feb14 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -363,7 +363,7 @@  static unsigned long global_dirtyable_memory(void)
 {
 	unsigned long x;
 
-	x = global_page_state(NR_FREE_PAGES);
+	x = global_zone_page_state(NR_FREE_PAGES);
 	/*
 	 * Pages reserved for the kernel should not be considered
 	 * dirtyable, to prevent a situation where reclaim has to
@@ -1405,7 +1405,7 @@  void wb_update_bandwidth(struct bdi_writeback *wb, unsigned long start_time)
  * will look to see if it needs to start dirty throttling.
  *
  * If dirty_poll_interval is too low, big NUMA machines will call the expensive
- * global_page_state() too often. So scale it near-sqrt to the safety margin
+ * global_zone_page_state() too often. So scale it near-sqrt to the safety margin
  * (the number of pages we may dirty without exceeding the dirty limits).
  */
 static unsigned long dirty_poll_interval(unsigned long dirty,
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 3e89731a86bd..ff153f7a0586 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4443,7 +4443,7 @@  long si_mem_available(void)
 	 * Estimate the amount of memory available for userspace allocations,
 	 * without causing swapping.
 	 */
-	available = global_page_state(NR_FREE_PAGES) - totalreserve_pages;
+	available = global_zone_page_state(NR_FREE_PAGES) - totalreserve_pages;
 
 	/*
 	 * Not all the page cache can be freed, otherwise the system will
@@ -4472,7 +4472,7 @@  void si_meminfo(struct sysinfo *val)
 {
 	val->totalram = totalram_pages;
 	val->sharedram = global_node_page_state(NR_SHMEM);
-	val->freeram = global_page_state(NR_FREE_PAGES);
+	val->freeram = global_zone_page_state(NR_FREE_PAGES);
 	val->bufferram = nr_blockdev_pages();
 	val->totalhigh = totalhigh_pages;
 	val->freehigh = nr_free_highpages();
@@ -4607,11 +4607,11 @@  void show_free_areas(unsigned int filter, nodemask_t *nodemask)
 		global_node_page_state(NR_SLAB_UNRECLAIMABLE),
 		global_node_page_state(NR_FILE_MAPPED),
 		global_node_page_state(NR_SHMEM),
-		global_page_state(NR_PAGETABLE),
-		global_page_state(NR_BOUNCE),
-		global_page_state(NR_FREE_PAGES),
+		global_zone_page_state(NR_PAGETABLE),
+		global_zone_page_state(NR_BOUNCE),
+		global_zone_page_state(NR_FREE_PAGES),
 		free_pcp,
-		global_page_state(NR_FREE_CMA_PAGES));
+		global_zone_page_state(NR_FREE_CMA_PAGES));
 
 	for_each_online_pgdat(pgdat) {
 		if (show_mem_node_skip(filter, pgdat->node_id, nodemask))
diff --git a/mm/util.c b/mm/util.c
index 9ecddf568fe3..34e57fae959d 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -614,7 +614,7 @@  int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
 		return 0;
 
 	if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
-		free = global_page_state(NR_FREE_PAGES);
+		free = global_zone_page_state(NR_FREE_PAGES);
 		free += global_node_page_state(NR_FILE_PAGES);
 
 		/*
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 9a4441bbeef2..4544d44e9594 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1500,7 +1500,7 @@  static void *vmstat_start(struct seq_file *m, loff_t *pos)
 	if (!v)
 		return ERR_PTR(-ENOMEM);
 	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
-		v[i] = global_page_state(i);
+		v[i] = global_zone_page_state(i);
 	v += NR_VM_ZONE_STAT_ITEMS;
 
 	for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
@@ -1589,7 +1589,7 @@  int vmstat_refresh(struct ctl_table *table, int write,
 	 * which can equally be echo'ed to or cat'ted from (by root),
 	 * can be used to update the stats just before reading them.
 	 *
-	 * Oh, and since global_page_state() etc. are so careful to hide
+	 * Oh, and since global_zone_page_state() etc. are so careful to hide
 	 * transiently negative values, report an error here if any of
 	 * the stats is negative, so we know to go looking for imbalance.
 	 */