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mm: show total hugetlb memory consumption in /proc/meminfo 

Currently we display some hugepage statistics (total, free, etc) in
/proc/meminfo, but only for default hugepage size (e.g.  2Mb).

If hugepages of different sizes are used (like 2Mb and 1Gb on x86-64),
/proc/meminfo output can be confusing, as non-default sized hugepages
are not reflected at all, and there are no signs that they are existing
and consuming system memory.

To solve this problem, let's display the total amount of memory,
consumed by hugetlb pages of all sized (both free and used).  Let's call
it "Hugetlb", and display size in kB to match generic /proc/meminfo
style.

For example, (1024 2Mb pages and 2 1Gb pages are pre-allocated):
  $ cat /proc/meminfo
  MemTotal:        8168984 kB
  MemFree:         3789276 kB
  <...>
  CmaFree:               0 kB
  HugePages_Total:    1024
  HugePages_Free:     1024
  HugePages_Rsvd:        0
  HugePages_Surp:        0
  Hugepagesize:       2048 kB
  Hugetlb:         4194304 kB
  DirectMap4k:       32632 kB
  DirectMap2M:     4161536 kB
  DirectMap1G:     6291456 kB

Also, this patch updates corresponding docs to reflect Hugetlb entry
meaning and difference between Hugetlb and HugePages_Total * Hugepagesize.

Link: http://lkml.kernel.org/r/20171115231409.12131-1-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Roman Gushchin 2018-01-31 16:16:22 -08:00 committed by Linus Torvalds
parent 9852a72123
commit fcb2b0c577
2 changed files with 42 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

27
Documentation/vm/hugetlbpage.txt
View File

@ -20,19 +20,20 @@ options.
The /proc/meminfo file provides information about the total number of The /proc/meminfo file provides information about the total number of
persistent hugetlb pages in the kernel's huge page pool. It also displays persistent hugetlb pages in the kernel's huge page pool. It also displays
information about the number of free, reserved and surplus huge pages and the default huge page size and information about the number of free, reserved
default huge page size. The huge page size is needed for generating the and surplus huge pages in the pool of huge pages of default size.
proper alignment and size of the arguments to system calls that map huge page The huge page size is needed for generating the proper alignment and
regions. size of the arguments to system calls that map huge page regions.
The output of "cat /proc/meminfo" will include lines like: The output of "cat /proc/meminfo" will include lines like:
..... .....
HugePages_Total: vvv HugePages_Total: uuu
HugePages_Free: www HugePages_Free: vvv
HugePages_Rsvd: xxx HugePages_Rsvd: www
HugePages_Surp: yyy HugePages_Surp: xxx
Hugepagesize: zzz kB Hugepagesize: yyy kB
Hugetlb: zzz kB
where: where:
HugePages_Total is the size of the pool of huge pages. HugePages_Total is the size of the pool of huge pages.
@ -47,6 +48,14 @@ HugePages_Surp is short for "surplus," and is the number of huge pages in
the pool above the value in /proc/sys/vm/nr_hugepages. The the pool above the value in /proc/sys/vm/nr_hugepages. The
maximum number of surplus huge pages is controlled by maximum number of surplus huge pages is controlled by
/proc/sys/vm/nr_overcommit_hugepages. /proc/sys/vm/nr_overcommit_hugepages.
Hugepagesize is the default hugepage size (in Kb).
Hugetlb is the total amount of memory (in kB), consumed by huge
pages of all sizes.
If huge pages of different sizes are in use, this number
will exceed HugePages_Total * Hugepagesize. To get more
detailed information, please, refer to
/sys/kernel/mm/hugepages (described below).
/proc/filesystems should also show a filesystem of type "hugetlbfs" configured /proc/filesystems should also show a filesystem of type "hugetlbfs" configured
in the kernel. in the kernel.

36
mm/hugetlb.c
View File

@ -2975,20 +2975,32 @@ out:
void hugetlb_report_meminfo(struct seq_file *m) void hugetlb_report_meminfo(struct seq_file *m)
{ {
struct hstate *h = &default_hstate; struct hstate *h;
unsigned long total = 0;
if (!hugepages_supported()) if (!hugepages_supported())
return; return;
seq_printf(m,
"HugePages_Total: %5lu\n" for_each_hstate(h) {
"HugePages_Free: %5lu\n" unsigned long count = h->nr_huge_pages;
"HugePages_Rsvd: %5lu\n"
"HugePages_Surp: %5lu\n" total += (PAGE_SIZE << huge_page_order(h)) * count;
"Hugepagesize: %8lu kB\n",
h->nr_huge_pages, if (h == &default_hstate)
h->free_huge_pages, seq_printf(m,
h->resv_huge_pages, "HugePages_Total: %5lu\n"
h->surplus_huge_pages, "HugePages_Free: %5lu\n"
1UL << (huge_page_order(h) + PAGE_SHIFT - 10)); "HugePages_Rsvd: %5lu\n"
"HugePages_Surp: %5lu\n"
"Hugepagesize: %8lu kB\n",
count,
h->free_huge_pages,
h->resv_huge_pages,
h->surplus_huge_pages,
(PAGE_SIZE << huge_page_order(h)) / 1024);
}
seq_printf(m, "Hugetlb: %8lu kB\n", total / 1024);
} }
int hugetlb_report_node_meminfo(int nid, char *buf) int hugetlb_report_node_meminfo(int nid, char *buf)