From: Roman Gushchin <guro@xxxxxx>
Subject: mm: vmalloc: show number of vmalloc pages in /proc/meminfo
Vmalloc() is getting more and more used these days (kernel stacks, bpf and
percpu allocator are new top users), and the total % of memory consumed by
vmalloc() can be pretty significant and changes dynamically.
/proc/meminfo is the best place to display this information: its top goal
is to show top consumers of the memory.
Since the VmallocUsed field in /proc/meminfo is not in use for quite a
long time (it has been defined to 0 by a5ad88ce8c7f ("mm: get rid of
'vmalloc_info' from /proc/meminfo")), let's reuse it for showing the
actual physical memory consumption of vmalloc().
Link: http://lkml.kernel.org/r/20190417194002.12369-3-guro@xxxxxx
Signed-off-by: Roman Gushchin <guro@xxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/meminfo.c | 2 +-
include/linux/vmalloc.h | 2 ++
mm/vmalloc.c | 10 ++++++++++
3 files changed, 13 insertions(+), 1 deletion(-)
--- a/fs/proc/meminfo.c~mm-show-number-of-vmalloc-pages-in-proc-meminfo
+++ a/fs/proc/meminfo.c
@@ -120,7 +120,7 @@ static int meminfo_proc_show(struct seq_
show_val_kb(m, "Committed_AS: ", committed);
seq_printf(m, "VmallocTotal: %8lu kB\n",
(unsigned long)VMALLOC_TOTAL >> 10);
- show_val_kb(m, "VmallocUsed: ", 0ul);
+ show_val_kb(m, "VmallocUsed: ", vmalloc_nr_pages());
show_val_kb(m, "VmallocChunk: ", 0ul);
show_val_kb(m, "Percpu: ", pcpu_nr_pages());
--- a/include/linux/vmalloc.h~mm-show-number-of-vmalloc-pages-in-proc-meminfo
+++ a/include/linux/vmalloc.h
@@ -72,10 +72,12 @@ extern void vm_unmap_aliases(void);
#ifdef CONFIG_MMU
extern void __init vmalloc_init(void);
+extern unsigned long vmalloc_nr_pages(void);
#else
static inline void vmalloc_init(void)
{
}
+static inline unsigned long vmalloc_nr_pages(void) { return 0; }
#endif
extern void *vmalloc(unsigned long size);
--- a/mm/vmalloc.c~mm-show-number-of-vmalloc-pages-in-proc-meminfo
+++ a/mm/vmalloc.c
@@ -406,6 +406,13 @@ static void purge_vmap_area_lazy(void);
static BLOCKING_NOTIFIER_HEAD(vmap_notify_list);
static unsigned long lazy_max_pages(void);
+static atomic_long_t nr_vmalloc_pages;
+
+unsigned long vmalloc_nr_pages(void)
+{
+ return atomic_long_read(&nr_vmalloc_pages);
+}
+
static struct vmap_area *__find_vmap_area(unsigned long addr)
{
struct rb_node *n = vmap_area_root.rb_node;
@@ -2237,6 +2244,7 @@ static void __vunmap(const void *addr, i
BUG_ON(!page);
__free_pages(page, 0);
}
+ atomic_long_sub(area->nr_pages, &nr_vmalloc_pages);
kvfree(area->pages);
}
@@ -2414,12 +2422,14 @@ static void *__vmalloc_area_node(struct
if (unlikely(!page)) {
/* Successfully allocated i pages, free them in __vunmap() */
area->nr_pages = i;
+ atomic_long_add(area->nr_pages, &nr_vmalloc_pages);
goto fail;
}
area->pages[i] = page;
if (gfpflags_allow_blocking(gfp_mask|highmem_mask))
cond_resched();
}
+ atomic_long_add(area->nr_pages, &nr_vmalloc_pages);
if (map_vm_area(area, prot, pages))
goto fail;
_
