Commit Graph

7346 Commits

Author SHA1 Message Date
Jianguo Wu
eee87e1726 mm/zbud: fix some trivial typos in comments
Signed-off-by: Jianguo Wu <wujianguo@huawei.com>
Cc: Seth Jennings <sjenning@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:35 -07:00
Xishi Qiu
37b000b640 mm/hotplug: remove unnecessary BUG_ON in __offline_pages()
I think we can remove "BUG_ON(start_pfn >= end_pfn)" in __offline_pages(),
because in memory_block_action() "nr_pages = PAGES_PER_SECTION * sections_per_block"
is always greater than 0.

memory_block_action()
	offline_pages()
		__offline_pages()
			BUG_ON(start_pfn >= end_pfn)

In v2.6.32, If info->length==0, this way may hit this BUG_ON().
acpi_memory_disable_device()
	remove_memory(info->start_addr, info->length)
			offline_pages()

A later Fujitsu patch renamed this function and the BUG_ON() is
unnecessary.

Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:35 -07:00
Joonsoo Kim
b136be5e0b mm, vmalloc: use well-defined find_last_bit() func
Our intention in here is to find last_bit within the region to flush.
There is well-defined function, find_last_bit() for this purpose and its
performance may be slightly better than current implementation.  So change
it.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:34 -07:00
Joonsoo Kim
6b70f7dff8 mm, vmalloc: remove useless variable in vmap_block
vbq in vmap_block isn't used. So remove it.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:33 -07:00
Christoph Lameter
fbc2edb053 vmstat: use this_cpu() to avoid irqon/off sequence in refresh_cpu_vm_stats
Disabling interrupts repeatedly can be avoided in the inner loop if we use
a this_cpu operation.

Signed-off-by: Christoph Lameter <cl@linux.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
CC: Tejun Heo <tj@kernel.org>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:31 -07:00
Christoph Lameter
4edb0748b2 vmstat: create fold_diff
Both functions that update global counters use the same mechanism.

Create a function that contains the common code.

Signed-off-by: Christoph Lameter <cl@linux.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
CC: Tejun Heo <tj@kernel.org>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:31 -07:00
Christoph Lameter
2bb921e526 vmstat: create separate function to fold per cpu diffs into local counters
The main idea behind this patchset is to reduce the vmstat update overhead
by avoiding interrupt enable/disable and the use of per cpu atomics.

This patch (of 3):

It is better to have a separate folding function because
refresh_cpu_vm_stats() also does other things like expire pages in the
page allocator caches.

If we have a separate function then refresh_cpu_vm_stats() is only called
from the local cpu which allows additional optimizations.

The folding function is only called when a cpu is being downed and
therefore no other processor will be accessing the counters.  Also
simplifies synchronization.

[akpm@linux-foundation.org: fix UP build]
Signed-off-by: Christoph Lameter <cl@linux.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
CC: Tejun Heo <tj@kernel.org>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:31 -07:00
Joonsoo Kim
d2cf5ad631 swap: clean-up #ifdef in page_mapping()
PageSwapCache() is always false when !CONFIG_SWAP, so compiler
properly discard related code. Therefore, we don't need #ifdef explicitly.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:31 -07:00
Joonsoo Kim
bc4b4448db mm: move pgtable related functions to right place
pgtable related functions are mostly in pgtable-generic.c.
So move remaining functions from memory.c to pgtable-generic.c.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:30 -07:00
Joonsoo Kim
e66f097257 mm, page_alloc: add unlikely macro to help compiler optimization
We rarely allocate a page with ALLOC_NO_WATERMARKS and it is used in slow
path.  For helping compiler optimization, add unlikely macro to
ALLOC_NO_WATERMARKS checking.

This patch doesn't have any effect now, because gcc already optimize this
properly.  But we cannot assume that gcc always does right and nobody
re-evaluate if gcc do proper optimization with their change, for example,
it is not optimized properly on v3.10.  So adding compiler hint here is
reasonable.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:29 -07:00
Jianguo Wu
1da6f0e1b3 mm/mempolicy: return NULL if node is NUMA_NO_NODE in get_task_policy
If node == NUMA_NO_NODE, pol is NULL, we should return NULL instead of
do "if (!pol->mode)" check.

[akpm@linux-foundation.org: reorganise code]
Signed-off-by: Jianguo Wu <wujianguo@huawei.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:29 -07:00
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
Joonsoo Kim
a63884e921 mm, hugetlb: remove decrement_hugepage_resv_vma()
Now, Checking condition of decrement_hugepage_resv_vma() and
vma_has_reserves() is same, so we can clean-up this function with
vma_has_reserves().  Additionally, decrement_hugepage_resv_vma() has only
one call site, so we can remove function and embed it into
dequeue_huge_page_vma() directly.  This patch implement it.

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
Joonsoo Kim
72231b03cc mm, hugetlb: add VM_NORESERVE check in vma_has_reserves()
If we map the region with MAP_NORESERVE and MAP_SHARED, we can skip to
check reserve counting and eventually we cannot be ensured to allocate a
huge page in fault time.  With following example code, you can easily find
this situation.

Assume 2MB, nr_hugepages = 100

        fd = hugetlbfs_unlinked_fd();
        if (fd < 0)
                return 1;

        size = 200 * 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;
        }

        size = 2 * MB;
        flag = MAP_ANONYMOUS | MAP_SHARED | MAP_HUGETLB | MAP_NORESERVE;
        p = mmap(NULL, size, PROT_READ|PROT_WRITE, flag, -1, 0);
        if (p == MAP_FAILED) {
                fprintf(stderr, "mmap() failed: %s\n", strerror(errno));
        }
        p[0] = '0';
        sleep(10);

During executing sleep(10), run 'cat /proc/meminfo' on another process.

HugePages_Free:       99
HugePages_Rsvd:      100

Number of free should be higher or equal than number of reserve, but this
aren't.  This represent that non reserved shared mapping steal a reserved
page.  Non reserved shared mapping should not eat into reserve space.

If we consider VM_NORESERVE in vma_has_reserve() and return 0 which mean
that we don't have reserved pages, then we check that we have enough free
pages in dequeue_huge_page_vma().  This prevent to steal a reserved page.

With this change, above test generate a SIGBUG which is correct, because
all free pages are reserved and non reserved shared mapping can't get a
free page.

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
Joonsoo Kim
37a2140dc2 mm, hugetlb: do not use a page in page cache for cow optimization
Currently, we use a page with mapped count 1 in page cache for cow
optimization.  If we find this condition, we don't allocate a new page and
copy contents.  Instead, we map this page directly.  This may introduce a
problem that writting to private mapping overwrite hugetlb file directly.
You can find this situation with following code.

        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;
        }
        p[0] = 's';
        fprintf(stdout, "BEFORE STEAL PRIVATE WRITE: %c\n", p[0]);
        munmap(p, size);

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

        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;
        }
        fprintf(stdout, "AFTER STEAL PRIVATE WRITE: %c\n", p[0]);
        munmap(p, size);

We can see that "AFTER STEAL PRIVATE WRITE: c", not "AFTER STEAL PRIVATE
WRITE: s".  If we turn off this optimization to a page in page cache, the
problem is disappeared.

So, I change the trigger condition of optimization.  If this page is not
AnonPage, we don't do optimization.  This makes this optimization turning
off for a page cache.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Hillf Danton <dhillf@gmail.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 15:57:27 -07:00
Joonsoo Kim
c0d934ba27 mm, hugetlb: remove redundant list_empty check in gather_surplus_pages()
If list is empty, list_for_each_entry_safe() doesn't do anything.  So,
this check is redundant.  Remove it.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
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>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.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 15:57:27 -07:00
Joonsoo Kim
b226102682 mm, hugetlb: fix and clean-up node iteration code to alloc or free
Current node iteration code have a minor problem which do one more node
rotation if we can't succeed to allocate.  For example, if we start to
allocate at node 0, we stop to iterate at node 0.  Then we start to
allocate at node 1 for next allocation.

I introduce new macros "for_each_node_mask_to_[alloc|free]" and fix and
clean-up node iteration code to alloc or free.  This makes code more
understandable.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Hillf Danton <dhillf@gmail.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.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 15:57:26 -07:00
Joonsoo Kim
81a6fcae3f mm, hugetlb: clean-up alloc_huge_page()
Unify successful allocation paths to make the code more readable.  There
are no functional changes.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.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 15:57:26 -07:00
Joonsoo Kim
c748c26294 mm, hugetlb: trivial commenting fix
The name of the mutex written in comment is wrong.  Fix it.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Hillf Danton <dhillf@gmail.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
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 15:57:25 -07:00
Joonsoo Kim
9966c4bbb1 mm, hugetlb: move up the code which check availability of free huge page
In this time we are holding a hugetlb_lock, so hstate values can't be
changed.  If we don't have any usable free huge page in this time, we
don't need to proceed with the processing.  So move this code up.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Hillf Danton <dhillf@gmail.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
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 15:57:24 -07:00
Johannes Weiner
72457c0a05 mm: revert "page-writeback.c: subtract min_free_kbytes from dirtyable memory"
This reverts commit 75f7ad8e04.  It was the result of a problem
observed with a 3.2 kernel and merged in 3.9, while the issue had been
resolved upstream in 3.3 (commit ab8fabd46f81: "mm: exclude reserved
pages from dirtyable memory").

The "reserved pages" are a superset of min_free_kbytes, thus this change
is redundant and confusing.  Revert it.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Paul Szabo <psz@maths.usyd.edu.au>
Cc: Rik van Riel <riel@redhat.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:23 -07:00
Johannes Weiner
81c0a2bb51 mm: page_alloc: fair zone allocator policy
Each zone that holds userspace pages of one workload must be aged at a
speed proportional to the zone size.  Otherwise, the time an individual
page gets to stay in memory depends on the zone it happened to be
allocated in.  Asymmetry in the zone aging creates rather unpredictable
aging behavior and results in the wrong pages being reclaimed, activated
etc.

But exactly this happens right now because of the way the page allocator
and kswapd interact.  The page allocator uses per-node lists of all zones
in the system, ordered by preference, when allocating a new page.  When
the first iteration does not yield any results, kswapd is woken up and the
allocator retries.  Due to the way kswapd reclaims zones below the high
watermark while a zone can be allocated from when it is above the low
watermark, the allocator may keep kswapd running while kswapd reclaim
ensures that the page allocator can keep allocating from the first zone in
the zonelist for extended periods of time.  Meanwhile the other zones
rarely see new allocations and thus get aged much slower in comparison.

The result is that the occasional page placed in lower zones gets
relatively more time in memory, even gets promoted to the active list
after its peers have long been evicted.  Meanwhile, the bulk of the
working set may be thrashing on the preferred zone even though there may
be significant amounts of memory available in the lower zones.

Even the most basic test -- repeatedly reading a file slightly bigger than
memory -- shows how broken the zone aging is.  In this scenario, no single
page should be able stay in memory long enough to get referenced twice and
activated, but activation happens in spades:

  $ grep active_file /proc/zoneinfo
      nr_inactive_file 0
      nr_active_file 0
      nr_inactive_file 0
      nr_active_file 8
      nr_inactive_file 1582
      nr_active_file 11994
  $ cat data data data data >/dev/null
  $ grep active_file /proc/zoneinfo
      nr_inactive_file 0
      nr_active_file 70
      nr_inactive_file 258753
      nr_active_file 443214
      nr_inactive_file 149793
      nr_active_file 12021

Fix this with a very simple round robin allocator.  Each zone is allowed a
batch of allocations that is proportional to the zone's size, after which
it is treated as full.  The batch counters are reset when all zones have
been tried and the allocator enters the slowpath and kicks off kswapd
reclaim.  Allocation and reclaim is now fairly spread out to all
available/allowable zones:

  $ grep active_file /proc/zoneinfo
      nr_inactive_file 0
      nr_active_file 0
      nr_inactive_file 174
      nr_active_file 4865
      nr_inactive_file 53
      nr_active_file 860
  $ cat data data data data >/dev/null
  $ grep active_file /proc/zoneinfo
      nr_inactive_file 0
      nr_active_file 0
      nr_inactive_file 666622
      nr_active_file 4988
      nr_inactive_file 190969
      nr_active_file 937

When zone_reclaim_mode is enabled, allocations will now spread out to all
zones on the local node, not just the first preferred zone (which on a 4G
node might be a tiny Normal zone).

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Paul Bolle <paul.bollee@gmail.com>
Cc: Zlatko Calusic <zcalusic@bitsync.net>
Tested-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:23 -07:00
Johannes Weiner
e085dbc52f mm: page_alloc: rearrange watermark checking in get_page_from_freelist
Allocations that do not have to respect the watermarks are rare
high-priority events.  Reorder the code such that per-zone dirty limits
and future checks important only to regular page allocations are ignored
in these extraordinary situations.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Paul Bolle <paul.bollee@gmail.com>
Tested-by: Zlatko Calusic <zcalusic@bitsync.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:22 -07:00
Johannes Weiner
892f795df1 mm: vmscan: fix numa reclaim balance problem in kswapd
The way the page allocator interacts with kswapd creates aging imbalances,
where the amount of time a userspace page gets in memory under reclaim
pressure is dependent on which zone, which node the allocator took the
page frame from.

#1 fixes missed kswapd wakeups on NUMA systems, which lead to some
   nodes falling behind for a full reclaim cycle relative to the other
   nodes in the system

#3 fixes an interaction where kswapd and a continuous stream of page
   allocations keep the preferred zone of a task between the high and
   low watermark (allocations succeed + kswapd does not go to sleep)
   indefinitely, completely underutilizing the lower zones and
   thrashing on the preferred zone

These patches are the aging fairness part of the thrash-detection based
file LRU balancing.  Andrea recommended to submit them separately as they
are bugfixes in their own right.

The following test ran a foreground workload (memcachetest) with
background IO of various sizes on a 4 node 8G system (similar results were
observed with single-node 4G systems):

parallelio
                                               BAS                    FAIRALLO
                                              BASE                   FAIRALLOC
Ops memcachetest-0M              5170.00 (  0.00%)           5283.00 (  2.19%)
Ops memcachetest-791M            4740.00 (  0.00%)           5293.00 ( 11.67%)
Ops memcachetest-2639M           2551.00 (  0.00%)           4950.00 ( 94.04%)
Ops memcachetest-4487M           2606.00 (  0.00%)           3922.00 ( 50.50%)
Ops io-duration-0M                  0.00 (  0.00%)              0.00 (  0.00%)
Ops io-duration-791M               55.00 (  0.00%)             18.00 ( 67.27%)
Ops io-duration-2639M             235.00 (  0.00%)            103.00 ( 56.17%)
Ops io-duration-4487M             278.00 (  0.00%)            173.00 ( 37.77%)
Ops swaptotal-0M                    0.00 (  0.00%)              0.00 (  0.00%)
Ops swaptotal-791M             245184.00 (  0.00%)              0.00 (  0.00%)
Ops swaptotal-2639M            468069.00 (  0.00%)         108778.00 ( 76.76%)
Ops swaptotal-4487M            452529.00 (  0.00%)          76623.00 ( 83.07%)
Ops swapin-0M                       0.00 (  0.00%)              0.00 (  0.00%)
Ops swapin-791M                108297.00 (  0.00%)              0.00 (  0.00%)
Ops swapin-2639M               169537.00 (  0.00%)          50031.00 ( 70.49%)
Ops swapin-4487M               167435.00 (  0.00%)          34178.00 ( 79.59%)
Ops minorfaults-0M            1518666.00 (  0.00%)        1503993.00 (  0.97%)
Ops minorfaults-791M          1676963.00 (  0.00%)        1520115.00 (  9.35%)
Ops minorfaults-2639M         1606035.00 (  0.00%)        1799717.00 (-12.06%)
Ops minorfaults-4487M         1612118.00 (  0.00%)        1583825.00 (  1.76%)
Ops majorfaults-0M                  6.00 (  0.00%)              0.00 (  0.00%)
Ops majorfaults-791M            13836.00 (  0.00%)             10.00 ( 99.93%)
Ops majorfaults-2639M           22307.00 (  0.00%)           6490.00 ( 70.91%)
Ops majorfaults-4487M           21631.00 (  0.00%)           4380.00 ( 79.75%)

                 BAS    FAIRALLO
                BASE   FAIRALLOC
User          287.78      460.97
System       2151.67     3142.51
Elapsed      9737.00     8879.34

                                   BAS    FAIRALLO
                                  BASE   FAIRALLOC
Minor Faults                  53721925    57188551
Major Faults                    392195       15157
Swap Ins                       2994854      112770
Swap Outs                      4907092      134982
Direct pages scanned                 0       41824
Kswapd pages scanned          32975063     8128269
Kswapd pages reclaimed         6323069     7093495
Direct pages reclaimed               0       41824
Kswapd efficiency                  19%         87%
Kswapd velocity               3386.573     915.414
Direct efficiency                 100%        100%
Direct velocity                  0.000       4.710
Percentage direct scans             0%          0%
Zone normal velocity          2011.338     550.661
Zone dma32 velocity           1365.623     369.221
Zone dma velocity                9.612       0.242
Page writes by reclaim    18732404.000  614807.000
Page writes file              13825312      479825
Page writes anon               4907092      134982
Page reclaim immediate           85490        5647
Sector Reads                  12080532      483244
Sector Writes                 88740508    65438876
Page rescued immediate               0           0
Slabs scanned                    82560       12160
Direct inode steals                  0           0
Kswapd inode steals              24401       40013
Kswapd skipped wait                  0           0
THP fault alloc                      6           8
THP collapse alloc                5481        5812
THP splits                          75          22
THP fault fallback                   0           0
THP collapse fail                    0           0
Compaction stalls                    0          54
Compaction success                   0          45
Compaction failures                  0           9
Page migrate success            881492       82278
Page migrate failure                 0           0
Compaction pages isolated            0       60334
Compaction migrate scanned           0       53505
Compaction free scanned              0     1537605
Compaction cost                    914          86
NUMA PTE updates              46738231    41988419
NUMA hint faults              31175564    24213387
NUMA hint local faults        10427393     6411593
NUMA pages migrated             881492       55344
AutoNUMA cost                   156221      121361

The overall runtime was reduced, throughput for both the foreground
workload as well as the background IO improved, major faults, swapping and
reclaim activity shrunk significantly, reclaim efficiency more than
quadrupled.

This patch:

When the page allocator fails to get a page from all zones in its given
zonelist, it wakes up the per-node kswapds for all zones that are at their
low watermark.

However, with a system under load the free pages in a zone can fluctuate
enough that the allocation fails but the kswapd wakeup is also skipped
while the zone is still really close to the low watermark.

When one node misses a wakeup like this, it won't be aged before all the
other node's zones are down to their low watermarks again.  And skipping a
full aging cycle is an obvious fairness problem.

Kswapd runs until the high watermarks are restored, so it should also be
woken when the high watermarks are not met.  This ages nodes more equally
and creates a safety margin for the page counter fluctuation.

By using zone_balanced(), it will now check, in addition to the watermark,
if compaction requires more order-0 pages to create a higher order page.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Paul Bolle <paul.bollee@gmail.com>
Tested-by: Zlatko Calusic <zcalusic@bitsync.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:22 -07:00
Libin
a8f531ebc3 mm/huge_memory.c: fix potential NULL pointer dereference
In collapse_huge_page() there is a race window between releasing the
mmap_sem read lock and taking the mmap_sem write lock, so find_vma() may
return NULL.  So check the return value to avoid NULL pointer dereference.

collapse_huge_page
	khugepaged_alloc_page
		up_read(&mm->mmap_sem)
	down_write(&mm->mmap_sem)
	vma = find_vma(mm, address)

Signed-off-by: Libin <huawei.libin@huawei.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: <stable@vger.kernel.org> # v3.0+
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:19 -07:00
Yinghai Lu
e2d0bd2b92 mm: kill one if loop in __free_pages_bootmem()
We should not check loop+1 with loop end in loop body.  Just duplicate two
lines code to avoid it.

That will help a bit when we have huge amount of pages on system with
16TiB memory.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Mel Gorman <mgorman@suse.de>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:19 -07:00
Srivatsa S. Bhat
f92310c187 mm/page_alloc.c: fix the value of fallback_migratetype in alloc_extfrag tracepoint()
In the current code, the value of fallback_migratetype that is printed
using the mm_page_alloc_extfrag tracepoint, is the value of the
migratetype *after* it has been set to the preferred migratetype (if the
ownership was changed).  Obviously that wouldn't have been the original
intent.  (We already have a separate 'change_ownership' field to tell
whether the ownership of the pageblock was changed from the
fallback_migratetype to the preferred type.)

The intent of the fallback_migratetype field is to show the migratetype
from which we borrowed pages in order to satisfy the allocation request.
So fix the code to print that value correctly.

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Cody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:19 -07:00
Srivatsa S. Bhat
fef903efcf mm/page_allo.c: restructure free-page stealing code and fix a bug
The free-page stealing code in __rmqueue_fallback() is somewhat hard to
follow, and has an incredible amount of subtlety hidden inside!

First off, there is a minor bug in the reporting of change-of-ownership of
pageblocks.  Under some conditions, we try to move upto
'pageblock_nr_pages' no.  of pages to the preferred allocation list.  But
we change the ownership of that pageblock to the preferred type only if we
manage to successfully move atleast half of that pageblock (or if
page_group_by_mobility_disabled is set).

However, the current code ignores the latter part and sets the
'migratetype' variable to the preferred type, irrespective of whether we
actually changed the pageblock migratetype of that block or not.  So, the
page_alloc_extfrag tracepoint can end up printing incorrect info (i.e.,
'change_ownership' might be shown as 1 when it must have been 0).

So fixing this involves moving the update of the 'migratetype' variable to
the right place.  But looking closer, we observe that the 'migratetype'
variable is used subsequently for checks such as "is_migrate_cma()".
Obviously the intent there is to check if the *fallback* type is
MIGRATE_CMA, but since we already set the 'migratetype' variable to
start_migratetype, we end up checking if the *preferred* type is
MIGRATE_CMA!!

To make things more interesting, this actually doesn't cause a bug in
practice, because we never change *anything* if the fallback type is CMA.

So, restructure the code in such a way that it is trivial to understand
what is going on, and also fix the above mentioned bug.  And while at it,
also add a comment explaining the subtlety behind the migratetype used in
the call to expand().

[akpm@linux-foundation.org: remove unneeded `inline', small coding-style fix]
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Cody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:19 -07:00
Pintu Kumar
b8af29418a mm/page_alloc.c: fix coding style and spelling
Fix all errors reported by checkpatch and some small spelling mistakes.

Signed-off-by: Pintu Kumar <pintu.k@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:18 -07:00
Shaohua Li
ebc2a1a691 swap: make cluster allocation per-cpu
swap cluster allocation is to get better request merge to improve
performance.  But the cluster is shared globally, if multiple tasks are
doing swap, this will cause interleave disk access.  While multiple tasks
swap is quite common, for example, each numa node has a kswapd thread
doing swap and multiple threads/processes doing direct page reclaim.

ioscheduler can't help too much here, because tasks don't send swapout IO
down to block layer in the meantime.  Block layer does merge some IOs, but
a lot not, depending on how many tasks are doing swapout concurrently.  In
practice, I've seen a lot of small size IO in swapout workloads.

We makes the cluster allocation per-cpu here.  The interleave disk access
issue goes away.  All tasks swapout to their own cluster, so swapout will
become sequential, which can be easily merged to big size IO.  If one CPU
can't get its per-cpu cluster (for example, there is no free cluster
anymore in the swap), it will fallback to scan swap_map.  The CPU can
still continue swap.  We don't need recycle free swap entries of other
CPUs.

In my test (swap to a 2-disk raid0 partition), this improves around 10%
swapout throughput, and request size is increased significantly.

How does this impact swap readahead is uncertain though.  On one side,
page reclaim always isolates and swaps several adjancent pages, this will
make page reclaim write the pages sequentially and benefit readahead.  On
the other side, several CPU write pages interleave means the pages don't
live _sequentially_ but relatively _near_.  In the per-cpu allocation
case, if adjancent pages are written by different cpus, they will live
relatively _far_.  So how this impacts swap readahead depends on how many
pages page reclaim isolates and swaps one time.  If the number is big,
this patch will benefit swap readahead.  Of course, this is about
sequential access pattern.  The patch has no impact for random access
pattern, because the new cluster allocation algorithm is just for SSD.

Alternative solution is organizing swap layout to be per-mm instead of
this per-cpu approach.  In the per-mm layout, we allocate a disk range for
each mm, so pages of one mm live in swap disk adjacently.  per-mm layout
has potential issues of lock contention if multiple reclaimers are swap
pages from one mm.  For a sequential workload, per-mm layout is better to
implement swap readahead, because pages from the mm are adjacent in disk.
But per-cpu layout isn't very bad in this workload, as page reclaim always
isolates and swaps several pages one time, such pages will still live in
disk sequentially and readahead can utilize this.  For a random workload,
per-mm layout isn't beneficial of request merge, because it's quite
possible pages from different mm are swapout in the meantime and IO can't
be merged in per-mm layout.  while with per-cpu layout we can merge
requests from any mm.  Considering random workload is more popular in
workloads with swap (and per-cpu approach isn't too bad for sequential
workload too), I'm choosing per-cpu layout.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Shaohua Li <shli@fusionio.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Kyungmin Park <kmpark@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rafael Aquini <aquini@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:17 -07:00
Shaohua Li
edfe23dac3 swap: fix races exposed by swap discard
The previous patch can expose races, according to Hugh:

swapoff was sometimes failing with "Cannot allocate memory", coming from
try_to_unuse()'s -ENOMEM: it needs to allow for swap_duplicate() failing
on a free entry temporarily SWAP_MAP_BAD while being discarded.

We should use ACCESS_ONCE() there, and whenever accessing swap_map
locklessly; but rather than peppering it throughout try_to_unuse(), just
declare *swap_map with volatile.

try_to_unuse() is accustomed to *swap_map going down racily, but not
necessarily to it jumping up from 0 to SWAP_MAP_BAD: we'll be safer to
prevent that transition once SWP_WRITEOK is switched off, when it's a
waste of time to issue discards anyway (swapon can do a whole discard).

Another issue is:

In swapin_readahead(), read_swap_cache_async() can read a bad swap entry,
because we don't check if readahead swap entry is bad.  This doesn't break
anything but such swapin page is wasteful and can only be freed at page
reclaim.  We should avoid read such swap entry.  And in discard, we mark
swap entry SWAP_MAP_BAD and then switch it to normal when discard is
finished.  If readahead reads such swap entry, we have the same issue, so
we much check if swap entry is bad too.

Thanks Hugh to inspire swapin_readahead could use bad swap entry.

[include Hugh's patch 'swap: fix swapoff ENOMEMs from discard']
Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Kyungmin Park <kmpark@infradead.org>
Cc: Rafael Aquini <aquini@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:16 -07:00
Shaohua Li
815c2c543d swap: make swap discard async
swap can do cluster discard for SSD, which is good, but there are some
problems here:

1. swap do the discard just before page reclaim gets a swap entry and
   writes the disk sectors.  This is useless for high end SSD, because an
   overwrite to a sector implies a discard to original sector too.  A
   discard + overwrite == overwrite.

2. the purpose of doing discard is to improve SSD firmware garbage
   collection.  Idealy we should send discard as early as possible, so
   firmware can do something smart.  Sending discard just after swap entry
   is freed is considered early compared to sending discard before write.
   Of course, if workload is already bound to gc speed, sending discard
   earlier or later doesn't make

3. block discard is a sync API, which will delay scan_swap_map()
   significantly.

4. Write and discard command can be executed parallel in PCIe SSD.
   Making swap discard async can make execution more efficiently.

This patch makes swap discard async and moves discard to where swap entry
is freed.  Discard and write have no dependence now, so above issues can
be avoided.  Idealy we should do discard for any freed sectors, but some
SSD discard is very slow.  This patch still does discard for a whole
cluster.

My test does a several round of 'mmap, write, unmap', which will trigger a
lot of swap discard.  In a fusionio card, with this patch, the test
runtime is reduced to 18% of the time without it, so around 5.5x faster.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Shaohua Li <shli@fusionio.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Kyungmin Park <kmpark@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rafael Aquini <aquini@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:15 -07:00
Shaohua Li
2a8f944934 swap: change block allocation algorithm for SSD
I'm using a fast SSD to do swap.  scan_swap_map() sometimes uses up to
20~30% CPU time (when cluster is hard to find, the CPU time can be up to
80%), which becomes a bottleneck.  scan_swap_map() scans a byte array to
search a 256 page cluster, which is very slow.

Here I introduced a simple algorithm to search cluster.  Since we only
care about 256 pages cluster, we can just use a counter to track if a
cluster is free.  Every 256 pages use one int to store the counter.  If
the counter of a cluster is 0, the cluster is free.  All free clusters
will be added to a list, so searching cluster is very efficient.  With
this, scap_swap_map() overhead disappears.

This might help low end SD card swap too.  Because if the cluster is
aligned, SD firmware can do flash erase more efficiently.

We only enable the algorithm for SSD.  Hard disk swap isn't fast enough
and has downside with the algorithm which might introduce regression (see
below).

The patch slightly changes which cluster is choosen.  It always adds free
cluster to list tail.  This can help wear leveling for low end SSD too.
And if no cluster found, the scan_swap_map() will do search from the end
of last cluster.  So if no cluster found, the scan_swap_map() will do
search from the end of last free cluster, which is random.  For SSD, this
isn't a problem at all.

Another downside is the cluster must be aligned to 256 pages, which will
reduce the chance to find a cluster.  I would expect this isn't a big
problem for SSD because of the non-seek penality.  (And this is the reason
I only enable the algorithm for SSD).

Signed-off-by: Shaohua Li <shli@fusionio.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Kyungmin Park <kmpark@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rafael Aquini <aquini@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:15 -07:00
Chen Gang
15ca220e1a mm/page_alloc.c: use '__paginginit' instead of '__init'
set_pageblock_order() may be called when memory hotplug, so need use
'__paginginit' instead of '__init'.

The related warning:

  The function __meminit .free_area_init_node() references
  a function __init .set_pageblock_order().
  If .set_pageblock_order is only used by .free_area_init_node then
  annotate .set_pageblock_order with a matching annotation.

Signed-off-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:13 -07:00
Jerry Zhou
a7e833182a mm: fix negative left shift count when PAGE_SHIFT > 20
When PAGE_SHIFT > 20, the result of "20 - PAGE_SHIFT" is negative. The
previous calculating here will generate an unexpected result. In
addition, if PAGE_SIZE >= 1MB, The memory size of "numentries" was
already integral multiple of 1MB.

Signed-off-by: Jerry Zhou <uulinux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:12 -07:00
Jingoo Han
3dbb95f789 mm: replace strict_strtoul() with kstrtoul()
The use of strict_strtoul() is not preferred, because strict_strtoul() is
obsolete.  Thus, kstrtoul() should be used.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:11 -07:00
Dave Hansen
6df46865ff mm: vmstats: track TLB flush stats on UP too
The previous patch doing vmstats for TLB flushes ("mm: vmstats: tlb flush
counters") effectively missed UP since arch/x86/mm/tlb.c is only compiled
for SMP.

UP systems do not do remote TLB flushes, so compile those counters out on
UP.

arch/x86/kernel/cpu/mtrr/generic.c calls __flush_tlb() directly.  This is
probably an optimization since both the mtrr code and __flush_tlb() write
cr4.  It would probably be safe to make that a flush_tlb_all() (and then
get these statistics), but the mtrr code is ancient and I'm hesitant to
touch it other than to just stick in the counters.

[akpm@linux-foundation.org: tweak comments]
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:09 -07:00
Dave Hansen
9824cf9753 mm: vmstats: tlb flush counters
I was investigating some TLB flush scaling issues and realized that we do
not have any good methods for figuring out how many TLB flushes we are
doing.

It would be nice to be able to do these in generic code, but the
arch-independent calls don't explicitly specify whether we actually need
to do remote flushes or not.  In the end, we really need to know if we
actually _did_ global vs.  local invalidations, so that leaves us with few
options other than to muck with the counters from arch-specific code.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:08 -07:00
Sunghan Suh
822518dc56 mm/zswap.c: get swapper address_space by using macro
There is a proper macro to get the corresponding swapper address space
from a swap entry.  Instead of directly accessing "swapper_spaces" array,
use the "swap_address_space" macro.

Signed-off-by: Sunghan Suh <sunghan.suh@samsung.com>
Reviewed-by: Bob Liu <bob.liu@oracle.com>
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:08 -07:00
Oleg Nesterov
e86867720e mm: mmap_region: kill correct_wcount/inode, use allow_write_access()
correct_wcount and inode in mmap_region() just complicate the code.  This
boolean was needed previously, when deny_write_access() was called before
vma_merge(), now we can simply check VM_DENYWRITE and do
allow_write_access() if it is set.

allow_write_access() checks file != NULL, so this is safe even if it was
possible to use VM_DENYWRITE && !file.  Just we need to ensure we use the
same file which was deny_write_access()'ed, so the patch also moves "file
= vma->vm_file" down after allow_write_access().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Colin Cross <ccross@android.com>
Cc: David Rientjes <rientjes@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:07 -07:00
Oleg Nesterov
077bf22b5c mm: do_mmap_pgoff: cleanup the usage of file_inode()
Simple cleanup.  Move "struct inode *inode" variable into "if (file)"
block to simplify the code and avoid the unnecessary check.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Colin Cross <ccross@android.com>
Cc: David Rientjes <rientjes@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:07 -07:00
Oleg Nesterov
b2c56e4f7d mm: shift VM_GROWS* check from mmap_region() to do_mmap_pgoff()
mmap() doesn't allow the non-anonymous mappings with VM_GROWS* bit set.
In particular this means that mmap_region()->vma_merge(file, vm_flags)
must always fail if "vm_flags & VM_GROWS" is set incorrectly.

So it does not make sense to check VM_GROWS* after we already allocated
the new vma, the only caller, do_mmap_pgoff(), which can pass this flag
can do the check itself.

And this looks a bit more correct, mmap_region() already unmapped the
old mapping at this stage. But if mmap() is going to fail, it should
avoid do_munmap() if possible.

Note: we check VM_GROWS at the end to ensure that do_mmap_pgoff() won't
return EINVAL in the case when it currently returns another error code.

Many thanks to Hugh who nacked the buggy v1.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:05 -07:00
Andrew Morton
465c47fd8d mm/swapfile.c: convert to pr_foo()
A few 80-col gymnastics were cleaned up as a result.

Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:03 -07:00
Raymond Jennings
d6bbbd29b1 swap: warn when a swap area overflows the maximum size
It is possible to swapon a swap area that is too big for the pte width
to handle.

Presently this failure happens silently.

Instead, emit a diagnostic to warn the user.

Testing results, root prompt commands and kernel log messages:

# lvresize /dev/system/swap --size 16G
# mkswap /dev/system/swap
# swapon /dev/system/swap

Jul  7 04:27:22 warfang kernel: Adding 16777212k swap
on /dev/mapper/system-swap.  Priority:-1 extents:1 across:16777212k

# lvresize /dev/system/swap --size 64G
# mkswap /dev/system/swap
# swapon /dev/system/swap

Jul  7 04:27:22 warfang kernel: Truncating oversized swap area, only
using 33554432k out of 67108860k
Jul  7 04:27:22 warfang kernel: Adding 33554428k swap
on /dev/mapper/system-swap.  Priority:-1 extents:1 across:33554428k

[akpm@linux-foundation.org: fix warning]
Signed-off-by: Raymond Jennings <shentino@gmail.com>
Acked-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:00 -07:00
Vladimir Cernov
ec9bed9d38 mm/madvise.c: fix coding-style errors
This fixes following errors:
	- ERROR: "(foo*)" should be "(foo *)"
	- ERROR: "foo ** bar" should be "foo **bar"

Signed-off-by: Vladimir Cernov <gg.kaspersky@gmail.com>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:00 -07:00
Oleg Nesterov
ef0855d334 mm: mempolicy: turn vma_set_policy() into vma_dup_policy()
Simple cleanup.  Every user of vma_set_policy() does the same work, this
looks a bit annoying imho.  And the new trivial helper which does
mpol_dup() + vma_set_policy() to simplify the callers.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:00 -07:00
Linus Torvalds
2e515bf096 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
Pull trivial tree from Jiri Kosina:
 "The usual trivial updates all over the tree -- mostly typo fixes and
  documentation updates"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (52 commits)
  doc: Documentation/cputopology.txt fix typo
  treewide: Convert retrun typos to return
  Fix comment typo for init_cma_reserved_pageblock
  Documentation/trace: Correcting and extending tracepoint documentation
  mm/hotplug: fix a typo in Documentation/memory-hotplug.txt
  power: Documentation: Update s2ram link
  doc: fix a typo in Documentation/00-INDEX
  Documentation/printk-formats.txt: No casts needed for u64/s64
  doc: Fix typo "is is" in Documentations
  treewide: Fix printks with 0x%#
  zram: doc fixes
  Documentation/kmemcheck: update kmemcheck documentation
  doc: documentation/hwspinlock.txt fix typo
  PM / Hibernate: add section for resume options
  doc: filesystems : Fix typo in Documentations/filesystems
  scsi/megaraid fixed several typos in comments
  ppc: init_32: Fix error typo "CONFIG_START_KERNEL"
  treewide: Add __GFP_NOWARN to k.alloc calls with v.alloc fallbacks
  page_isolation: Fix a comment typo in test_pages_isolated()
  doc: fix a typo about irq affinity
  ...
2013-09-06 09:36:28 -07:00
Linus Torvalds
45d9a2220f Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs pile 1 from Al Viro:
 "Unfortunately, this merge window it'll have a be a lot of small piles -
  my fault, actually, for not keeping #for-next in anything that would
  resemble a sane shape ;-/

  This pile: assorted fixes (the first 3 are -stable fodder, IMO) and
  cleanups + %pd/%pD formats (dentry/file pathname, up to 4 last
  components) + several long-standing patches from various folks.

  There definitely will be a lot more (starting with Miklos'
  check_submount_and_drop() series)"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (26 commits)
  direct-io: Handle O_(D)SYNC AIO
  direct-io: Implement generic deferred AIO completions
  add formats for dentry/file pathnames
  kvm eventfd: switch to fdget
  powerpc kvm: use fdget
  switch fchmod() to fdget
  switch epoll_ctl() to fdget
  switch copy_module_from_fd() to fdget
  git simplify nilfs check for busy subtree
  ibmasmfs: don't bother passing superblock when not needed
  don't pass superblock to hypfs_{mkdir,create*}
  don't pass superblock to hypfs_diag_create_files
  don't pass superblock to hypfs_vm_create_files()
  oprofile: get rid of pointless forward declarations of struct super_block
  oprofilefs_create_...() do not need superblock argument
  oprofilefs_mkdir() doesn't need superblock argument
  don't bother with passing superblock to oprofile_create_stats_files()
  oprofile: don't bother with passing superblock to ->create_files()
  don't bother passing sb to oprofile_create_files()
  coh901318: don't open-code simple_read_from_buffer()
  ...
2013-09-05 08:50:26 -07:00
Linus Torvalds
ae7a835cc5 Merge branch 'next' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Gleb Natapov:
 "The highlights of the release are nested EPT and pv-ticketlocks
  support (hypervisor part, guest part, which is most of the code, goes
  through tip tree).  Apart of that there are many fixes for all arches"

Fix up semantic conflicts as discussed in the pull request thread..

* 'next' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (88 commits)
  ARM: KVM: Add newlines to panic strings
  ARM: KVM: Work around older compiler bug
  ARM: KVM: Simplify tracepoint text
  ARM: KVM: Fix kvm_set_pte assignment
  ARM: KVM: vgic: Bump VGIC_NR_IRQS to 256
  ARM: KVM: Bugfix: vgic_bytemap_get_reg per cpu regs
  ARM: KVM: vgic: fix GICD_ICFGRn access
  ARM: KVM: vgic: simplify vgic_get_target_reg
  KVM: MMU: remove unused parameter
  KVM: PPC: Book3S PR: Rework kvmppc_mmu_book3s_64_xlate()
  KVM: PPC: Book3S PR: Make instruction fetch fallback work for system calls
  KVM: PPC: Book3S PR: Don't corrupt guest state when kernel uses VMX
  KVM: x86: update masterclock when kvmclock_offset is calculated (v2)
  KVM: PPC: Book3S: Fix compile error in XICS emulation
  KVM: PPC: Book3S PR: return appropriate error when allocation fails
  arch: powerpc: kvm: add signed type cast for comparation
  KVM: x86: add comments where MMIO does not return to the emulator
  KVM: vmx: count exits to userspace during invalid guest emulation
  KVM: rename __kvm_io_bus_sort_cmp to kvm_io_bus_cmp
  kvm: optimize away THP checks in kvm_is_mmio_pfn()
  ...
2013-09-04 18:15:06 -07:00
Linus Torvalds
27703bb4a6 PTR_RET() is a weird name, and led to some confusing usage. We ended
up with PTR_ERR_OR_ZERO(), and replacing or fixing all the usages.
 
 This has been sitting in linux-next for a whole cycle.
 
 Thanks,
 Rusty.
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1.4.12 (GNU/Linux)
 
 iQIcBAABAgAGBQJSJo+1AAoJENkgDmzRrbjxIC4QALJK95o8AUXuwUkl+2fmFkUt
 hh2/PJ1vDYgk4Xt0J6hyoK7XMa0H1RkbBrROuDdsBnorMFpEsGcgdkUZte9ufoAS
 97Bg+7N0KPbTB/S8vOwtW1vbERTJIVPN2uf6h1Wqm9Xc2puCh3HbMMr1AWMGu0WQ
 NqY5+Zz8zecy1UOrMhEP6H1CjeQcL1w1DO6YM5ydeqlKNzAz+JMfDXriLPDwiE7+
 XFPDF/O3Vtd2ckA7L70Lio7hfHwxV5U4WwFVfiwls98XB4jcZqDKIoh1r8z4SRgR
 +0Rae2DN3BaOabGMr//5XdrzQVpwJTh5m2w8BAOHJvCJ9HR7Sq29UIN4u+TowZBy
 L2xYo4dvFxkympwu5zEd3c7vHYWKIaqmSq5PIjr4gF/uIo2OeOTrpPIK782ZEYb7
 e+qUgOEM05V9AmQZCrSZeP9u474Sj8ow3sCtWxfdRtwNfoEIcUXsNNJd/zDHlVtW
 cEtXqc2xXIpcuUJQWlSaGp8fmRQjVZPzrLKYLM2m39ZcOOJbf5rzQAYS7hHPosIa
 SK+YVux/+Zzi+Xo/vXq1OlM/SruCr5S7JOgCxLowoQ88vupgXME6uPyC8EO+QQ50
 GsrHes5ZNLbk0uVsfcexIyojkUnyvDmmnDpv+1zdC6RgZLJQn8OXp5yNhHhnhrFT
 BiHX6YFWtDDqRlVv8Q0F
 =LeaW
 -----END PGP SIGNATURE-----

Merge tag 'PTR_RET-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull PTR_RET() removal patches from Rusty Russell:
 "PTR_RET() is a weird name, and led to some confusing usage.  We ended
  up with PTR_ERR_OR_ZERO(), and replacing or fixing all the usages.

  This has been sitting in linux-next for a whole cycle"

[ There are still some PTR_RET users scattered about, with some of them
  possibly being new, but most of them existing in Rusty's tree too.  We
  have that

      #define PTR_RET(p) PTR_ERR_OR_ZERO(p)

  thing in <linux/err.h>, so they continue to work for now  - Linus ]

* tag 'PTR_RET-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  GFS2: Replace PTR_RET with PTR_ERR_OR_ZERO
  Btrfs: volume: Replace PTR_RET with PTR_ERR_OR_ZERO
  drm/cma: Replace PTR_RET with PTR_ERR_OR_ZERO
  sh_veu: Replace PTR_RET with PTR_ERR_OR_ZERO
  dma-buf: Replace PTR_RET with PTR_ERR_OR_ZERO
  drivers/rtc: Replace PTR_RET with PTR_ERR_OR_ZERO
  mm/oom_kill: remove weird use of ERR_PTR()/PTR_ERR().
  staging/zcache: don't use PTR_RET().
  remoteproc: don't use PTR_RET().
  pinctrl: don't use PTR_RET().
  acpi: Replace weird use of PTR_RET.
  s390: Replace weird use of PTR_RET.
  PTR_RET is now PTR_ERR_OR_ZERO(): Replace most.
  PTR_RET is now PTR_ERR_OR_ZERO
2013-09-04 17:31:11 -07:00