kernel_optimize_test/mm
Joonsoo Kim af0ed73e69 mm, hugetlb: decrement reserve count if VM_NORESERVE alloc page cache
If a vma with VM_NORESERVE allocate a new page for page cache, we should
check whether this area is reserved or not.  If this address is already
reserved by other process(in case of chg == 0), we should decrement
reserve count, because this allocated page will go into page cache and
currently, there is no way to know that this page comes from reserved pool
or not when releasing inode.  This may introduce over-counting problem to
reserved count.  With following example code, you can easily reproduce
this situation.

Assume 2MB, nr_hugepages = 100

        size = 20 * MB;
        flag = MAP_SHARED;
        p = mmap(NULL, size, PROT_READ|PROT_WRITE, flag, fd, 0);
        if (p == MAP_FAILED) {
                fprintf(stderr, "mmap() failed: %s\n", strerror(errno));
                return -1;
        }

        flag = MAP_SHARED | MAP_NORESERVE;
        q = mmap(NULL, size, PROT_READ|PROT_WRITE, flag, fd, 0);
        if (q == MAP_FAILED) {
                fprintf(stderr, "mmap() failed: %s\n", strerror(errno));
        }
        q[0] = 'c';

After finish the program, run 'cat /proc/meminfo'.  You can see below
result.

HugePages_Free:      100
HugePages_Rsvd:        1

To fix this, we should check our mapping type and tracked region.  If our
mapping is VM_NORESERVE, VM_MAYSHARE and chg is 0, this imply that current
allocated page will go into page cache which is already reserved region
when mapping is created.  In this case, we should decrease reserve count.
As implementing above, this patch solve the problem.

[akpm@linux-foundation.org: fix spelling in comment]
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Hillf Danton <dhillf@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Davidlohr Bueso <davidlohr.bueso@hp.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:28 -07:00
..
backing-dev.c backing-dev: convert class code to use dev_groups 2013-08-19 21:22:34 -07:00
balloon_compaction.c
bootmem.c mm: kill free_all_bootmem_node() 2013-07-03 16:07:39 -07:00
bounce.c Merge branch 'for-3.10/core' of git://git.kernel.dk/linux-block 2013-05-08 10:13:35 -07:00
cleancache.c mm: cleancache: clean up cleancache_enabled 2013-04-30 17:04:01 -07:00
compaction.c
debug-pagealloc.c
dmapool.c
fadvise.c
failslab.c
filemap_xip.c lift sb_start_write() out of ->write() 2013-04-09 14:12:56 -04:00
filemap.c direct-io: Handle O_(D)SYNC AIO 2013-09-04 09:23:46 -04:00
fremap.c mm: save soft-dirty bits on file pages 2013-08-13 17:57:48 -07:00
frontswap.c frontswap: fix incorrect zeroing and allocation size for frontswap_map 2013-06-12 16:29:46 -07:00
highmem.c
huge_memory.c mm/huge_memory.c: fix potential NULL pointer dereference 2013-09-11 15:57:19 -07:00
hugetlb_cgroup.c cgroup: pass around cgroup_subsys_state instead of cgroup in file methods 2013-08-08 20:11:24 -04:00
hugetlb.c mm, hugetlb: decrement reserve count if VM_NORESERVE alloc page cache 2013-09-11 15:57:28 -07:00
hwpoison-inject.c
init-mm.c
internal.h mm: remove unused __put_page() 2013-07-09 10:33:22 -07:00
interval_tree.c
Kconfig Merge remote-tracking branch 'origin/next' into kvm-ppc-next 2013-08-29 00:41:59 +02:00
Kconfig.debug
kmemcheck.c
kmemleak-test.c
kmemleak.c mm: replace strict_strtoul() with kstrtoul() 2013-09-11 15:57:11 -07:00
ksm.c mm: replace strict_strtoul() with kstrtoul() 2013-09-11 15:57:11 -07:00
maccess.c
madvise.c mm/madvise.c: fix coding-style errors 2013-09-11 15:57:00 -07:00
Makefile zswap: add to mm/ 2013-07-10 18:11:34 -07:00
memblock.c mm/memblock.c: fix wrong comment in __next_free_mem_range() 2013-07-09 10:33:23 -07:00
memcontrol.c Merge branch 'for-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2013-09-03 18:25:03 -07:00
memory_hotplug.c mm/memory_hotplug.c: fix return value of online_pages() 2013-07-09 10:33:25 -07:00
memory-failure.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2013-09-06 09:36:28 -07:00
memory.c Merge 3.11-rc6 into char-misc-next 2013-08-18 20:40:33 -07:00
mempolicy.c mm: mempolicy: turn vma_set_policy() into vma_dup_policy() 2013-09-11 15:57:00 -07:00
mempool.c
migrate.c mm: migration: add migrate_entry_wait_huge() 2013-06-12 16:29:46 -07:00
mincore.c
mlock.c Revert "mm: introduce VM_POPULATE flag to better deal with racy userspace programs" 2013-03-28 17:45:51 -07:00
mm_init.c mm: tune vm_committed_as percpu_counter batching size 2013-07-03 16:07:32 -07:00
mmap.c mm: mmap_region: kill correct_wcount/inode, use allow_write_access() 2013-09-11 15:57:07 -07:00
mmu_context.c mm: remove old aio use_mm() comment 2013-05-07 18:38:27 -07:00
mmu_notifier.c treewide: relase -> release 2013-06-28 14:34:33 +02:00
mmzone.c
mprotect.c
mremap.c mm: move_ptes -- Set soft dirty bit depending on pte type 2013-08-27 09:36:17 -07:00
msync.c
nobootmem.c mm: concentrate modification of totalram_pages into the mm core 2013-07-03 16:07:33 -07:00
nommu.c mm: remove free_area_cache 2013-07-10 18:11:34 -07:00
oom_kill.c mm/oom_kill: remove weird use of ERR_PTR()/PTR_ERR(). 2013-07-15 11:25:05 +09:30
page_alloc.c mm: page_alloc: fair zone allocator policy 2013-09-11 15:57:23 -07:00
page_cgroup.c
page_io.c mm: remove compressed copy from zram in-memory 2013-07-03 16:07:26 -07:00
page_isolation.c page_isolation: Fix a comment typo in test_pages_isolated() 2013-08-20 13:03:41 +02:00
page-writeback.c mm: revert "page-writeback.c: subtract min_free_kbytes from dirtyable memory" 2013-09-11 15:57:23 -07:00
pagewalk.c mm/pagewalk.c: walk_page_range should avoid VM_PFNMAP areas 2013-05-24 16:22:53 -07:00
percpu-km.c
percpu-vm.c
percpu.c
pgtable-generic.c mm/THP: add pmd args to pgtable deposit and withdraw APIs 2013-06-20 16:55:07 +10:00
process_vm_access.c
quicklist.c
readahead.c mm: change invalidatepage prototype to accept length 2013-05-21 23:17:23 -04:00
rmap.c s390/mm: implement software referenced bits 2013-08-29 13:20:11 +02:00
shmem.c shm_mnt is as longterm as it gets, TYVM... 2013-09-03 22:50:27 -04:00
slab_common.c Merge branch 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux 2013-07-14 15:14:29 -07:00
slab.c kernel: delete __cpuinit usage from all core kernel files 2013-07-14 19:36:59 -04:00
slab.h memcg: check that kmem_cache has memcg_params before accessing it 2013-08-28 19:26:38 -07:00
slob.c Merge branch 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux 2013-07-14 15:14:29 -07:00
slub.c mm: replace strict_strtoul() with kstrtoul() 2013-09-11 15:57:11 -07:00
sparse-vmemmap.c sparse-vmemmap: specify vmemmap population range in bytes 2013-04-29 15:54:35 -07:00
sparse.c mm/sparse.c: put clear_hwpoisoned_pages within CONFIG_MEMORY_HOTREMOVE 2013-07-09 10:33:22 -07:00
swap_state.c swap: avoid read_swap_cache_async() race to deadlock while waiting on discard I/O completion 2013-06-12 16:29:45 -07:00
swap.c thp, mm: avoid PageUnevictable on active/inactive lru lists 2013-07-31 14:41:03 -07:00
swapfile.c swap: make cluster allocation per-cpu 2013-09-11 15:57:17 -07:00
truncate.c mm: teach truncate_inode_pages_range() to handle non page aligned ranges 2013-05-27 23:32:35 -04:00
util.c mm: remove free_area_cache 2013-07-10 18:11:34 -07:00
vmalloc.c mm/vmalloc.c: fix an overflow bug in alloc_vmap_area() 2013-07-09 10:33:23 -07:00
vmpressure.c Merge branch 'for-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2013-09-03 18:25:03 -07:00
vmscan.c mm: vmscan: fix numa reclaim balance problem in kswapd 2013-09-11 15:57:22 -07:00
vmstat.c mm: page_alloc: fair zone allocator policy 2013-09-11 15:57:23 -07:00
zbud.c mm: zbud: fix condition check on allocation size 2013-07-31 14:41:03 -07:00
zswap.c mm/zswap.c: get swapper address_space by using macro 2013-09-11 15:57:08 -07:00