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Commit db70fefd authored by Roman Gushchin's avatar Roman Gushchin Committed by Gerrit - the friendly Code Review server
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mm: 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 the
commit a5ad88ce ("mm: get rid of 'vmalloc_info' from
/proc/meminfo")), let's reuse it for showing the actual
physical memory consumption of vmalloc().

Change-Id: Ice4fd4b94c9c156b463487aaef033a8f8c3aa821
Signed-off-by: default avatarRoman Gushchin <guro@fb.com>
Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Patch-mainline: linux-mm @ Mon, 25 Feb 2019 12:30:37 -0800
Signed-off-by: default avatarVijayanand Jitta <vjitta@codeaurora.org>
Signed-off-by: default avatarVinayak Menon <vinmenon@codeaurora.org>
parent 02fae9c2

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
@@ -63,10 +63,12 @@ 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
@@ -340,6 +340,13 @@ static unsigned long cached_align; 


static unsigned long vmap_area_pcpu_hole;



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;
@@ -1525,6 +1532,7 @@ 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);

	}
@@ -1690,12 +1698,14 @@ 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;