Commit 97105f0a authored by Roman Gushchin's avatar Roman Gushchin Committed by Linus Torvalds
Browse files

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 a5ad88ce ("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@fb.com


Signed-off-by: default avatarRoman Gushchin <guro@fb.com>
Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
Reviewed-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ee2ad71b

fs/proc/meminfo.c

+1 −1
Original line number Diff line number Diff line
@@ -120,7 +120,7 @@ static int meminfo_proc_show(struct seq_file *m, void *v) 
	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());

include/linux/vmalloc.h

+2 −0
Original line number Diff line number Diff line
@@ -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);

mm/vmalloc.c

+10 −0
Original line number Diff line number Diff line
@@ -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, int deallocate_pages) 
			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 vm_struct *area, gfp_t gfp_mask, 
		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;

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