N_HIGH_MEMORY stands for the nodes that has normal or high memory.
N_MEMORY stands for the nodes that has any memory.
The code here need to handle with the nodes which have memory, we should
use N_MEMORY instead.
Since we introduced N_MEMORY, we update the initialization of node_states.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Lin Feng <linfeng@cn.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We have N_NORMAL_MEMORY for standing for the nodes that have normal memory
with zone_type <= ZONE_NORMAL.
And we have N_HIGH_MEMORY for standing for the nodes that have normal or
high memory.
But we don't have any word to stand for the nodes that have *any* memory.
And we have N_CPU but without N_MEMORY.
Current code reuse the N_HIGH_MEMORY for this purpose because any node
which has memory must have high memory or normal memory currently.
A) But this reusing is bad for *readability*. Because the name
N_HIGH_MEMORY just stands for high or normal:
A.example 1)
mem_cgroup_nr_lru_pages():
for_each_node_state(nid, N_HIGH_MEMORY)
The user will be confused(why this function just counts for high or
normal memory node? does it counts for ZONE_MOVABLE's lru pages?)
until someone else tell them N_HIGH_MEMORY is reused to stand for
nodes that have any memory.
A.cont) If we introduce N_MEMORY, we can reduce this confusing
AND make the code more clearly:
A.example 2) mm/page_cgroup.c use N_HIGH_MEMORY twice:
One is in page_cgroup_init(void):
for_each_node_state(nid, N_HIGH_MEMORY) {
It means if the node have memory, we will allocate page_cgroup map for
the node. We should use N_MEMORY instead here to gaim more clearly.
The second using is in alloc_page_cgroup():
if (node_state(nid, N_HIGH_MEMORY))
addr = vzalloc_node(size, nid);
It means if the node has high or normal memory that can be allocated
from kernel. We should keep N_HIGH_MEMORY here, and it will be better
if the "any memory" semantic of N_HIGH_MEMORY is removed.
B) This reusing is out-dated if we introduce MOVABLE-dedicated node.
The MOVABLE-dedicated node should not appear in
node_stats[N_HIGH_MEMORY] nor node_stats[N_NORMAL_MEMORY],
because MOVABLE-dedicated node has no high or normal memory.
In x86_64, N_HIGH_MEMORY=N_NORMAL_MEMORY, if a MOVABLE-dedicated node
is in node_stats[N_HIGH_MEMORY], it is also means it is in
node_stats[N_NORMAL_MEMORY], it causes SLUB wrong.
The slub uses
for_each_node_state(nid, N_NORMAL_MEMORY)
and creates kmem_cache_node for MOVABLE-dedicated node and cause problem.
In one word, we need a N_MEMORY. We just intrude it as an alias to
N_HIGH_MEMORY and fix all im-proper usages of N_HIGH_MEMORY in late
patches.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: Hillf Danton <dhillf@gmail.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Cc: Lin Feng <linfeng@cn.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
__alloc_contig_migrate_range() should use all possible ways to get all the
pages migrated from the given memory range, so pruning per-cpu lru lists
for all CPUs is required, regadless the cost of such operation. Otherwise
some pages which got stuck at per-cpu lru list might get missed by
migration procedure causing the contiguous allocation to fail.
Reported-by: SeongHwan Yoon <sunghwan.yun@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
hzp_alloc is incremented every time a huge zero page is successfully
allocated. It includes allocations which where dropped due
race with other allocation. Note, it doesn't count every map
of the huge zero page, only its allocation.
hzp_alloc_failed is incremented if kernel fails to allocate huge zero
page and falls back to using small pages.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@linux.intel.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
H. Peter Anvin doesn't like huge zero page which sticks in memory forever
after the first allocation. Here's implementation of lockless refcounting
for huge zero page.
We have two basic primitives: {get,put}_huge_zero_page(). They
manipulate reference counter.
If counter is 0, get_huge_zero_page() allocates a new huge page and takes
two references: one for caller and one for shrinker. We free the page
only in shrinker callback if counter is 1 (only shrinker has the
reference).
put_huge_zero_page() only decrements counter. Counter is never zero in
put_huge_zero_page() since shrinker holds on reference.
Freeing huge zero page in shrinker callback helps to avoid frequent
allocate-free.
Refcounting has cost. On 4 socket machine I observe ~1% slowdown on
parallel (40 processes) read page faulting comparing to lazy huge page
allocation. I think it's pretty reasonable for synthetic benchmark.
[lliubbo@gmail.com: fix mismerge]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@linux.intel.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Bob Liu <lliubbo@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We can't split huge zero page itself (and it's bug if we try), but we
can split the pmd which points to it.
On splitting the pmd we create a table with all ptes set to normal zero
page.
[akpm@linux-foundation.org: fix build error]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@linux.intel.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Lai Jiangshan
Marek Szyprowski
Thierry Reding
Kirill A. Shutemov