| Commit message (Collapse) | Author | Age | Files | Lines |
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Add a working sysctl to enable/disable automatic numa memory balancing
at runtime.
This allows us to track down performance problems with this feature and
is generally a good idea.
This was possible earlier through debugfs, but only with special
debugging options set. Also fix the boot message.
[akpm@linux-foundation.org: s/sched_numa_balancing/sysctl_numa_balancing/]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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When calling free_all_bootmem() the free areas under memblock's control
are released to the buddy allocator. Additionally the reserved list is
freed if it was reallocated by memblock. The same should apply for the
memory list.
Signed-off-by: Philipp Hachtmann <phacht@linux.vnet.ibm.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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When memblock_reserve() fails because memblock.reserved.regions cannot
be resized, the caller (e.g. alloc_bootmem()) is not informed of the
failed allocation. Therefore alloc_bootmem() silently returns the same
pointer again and again.
This patch adds a check for the return value of memblock_reserve() in
__alloc_memory_core().
Signed-off-by: Philipp Hachtmann <phacht@linux.vnet.ibm.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tang Chen <tangchen@cn.fujitsu.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>
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Currently we take both the memcg_create_mutex and the set_limit_mutex
when we enable kmem accounting for a memory cgroup, which makes kmem
activation events serialize with both memcg creations and other memcg
limit updates (memory.limit, memory.memsw.limit). However, there is no
point in such strict synchronization rules there.
First, the set_limit_mutex was introduced to keep the memory.limit and
memory.memsw.limit values in sync. Since memory.kmem.limit can be set
independently of them, it is better to introduce a separate mutex to
synchronize against concurrent kmem limit updates.
Second, we take the memcg_create_mutex in order to make sure all
children of this memcg will be kmem-active as well. For achieving that,
it is enough to hold this mutex only while checking if
memcg_has_children() though. This guarantees that if a child is added
after we checked that the memcg has no children, the newly added cgroup
will see its parent kmem-active (of course if the latter succeeded), and
call kmem activation for itself.
This patch simplifies the locking rules of memcg_update_kmem_limit()
according to these considerations.
[vdavydov@parallels.com: fix unintialized var warning]
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Glauber Costa <glommer@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Currently we have two state bits in mem_cgroup::kmem_account_flags
regarding kmem accounting activation, ACTIVATED and ACTIVE. We start
kmem accounting only if both flags are set (memcg_can_account_kmem()),
plus throughout the code there are several places where we check only
the ACTIVE flag, but we never check the ACTIVATED flag alone. These
flags are both set from memcg_update_kmem_limit() under the
set_limit_mutex, the ACTIVE flag always being set after ACTIVATED, and
they never get cleared. That said checking if both flags are set is
equivalent to checking only for the ACTIVE flag, and since there is no
ACTIVATED flag checks, we can safely remove the ACTIVATED flag, and
nothing will change.
Let's try to understand what was the reason for introducing these flags.
The purpose of the ACTIVE flag is clear - it states that kmem should be
accounting to the cgroup. The only requirement for it is that it should
be set after we have fully initialized kmem accounting bits for the
cgroup and patched all static branches relating to kmem accounting.
Since we always check if static branch is enabled before actually
considering if we should account (otherwise we wouldn't benefit from
static branching), this guarantees us that we won't skip a commit or
uncharge after a charge due to an unpatched static branch.
Now let's move on to the ACTIVATED bit. As I proved in the beginning of
this message, it is absolutely useless, and removing it will change
nothing. So what was the reason introducing it?
The ACTIVATED flag was introduced by commit a8964b9b84f9 ("memcg: use
static branches when code not in use") in order to guarantee that
static_key_slow_inc(&memcg_kmem_enabled_key) would be called only once
for each memory cgroup when its kmem accounting was activated. The
point was that at that time the memcg_update_kmem_limit() function's
work-flow looked like this:
bool must_inc_static_branch = false;
cgroup_lock();
mutex_lock(&set_limit_mutex);
if (!memcg->kmem_account_flags && val != RESOURCE_MAX) {
/* The kmem limit is set for the first time */
ret = res_counter_set_limit(&memcg->kmem, val);
memcg_kmem_set_activated(memcg);
must_inc_static_branch = true;
} else
ret = res_counter_set_limit(&memcg->kmem, val);
mutex_unlock(&set_limit_mutex);
cgroup_unlock();
if (must_inc_static_branch) {
/* We can't do this under cgroup_lock */
static_key_slow_inc(&memcg_kmem_enabled_key);
memcg_kmem_set_active(memcg);
}
So that without the ACTIVATED flag we could race with other threads
trying to set the limit and increment the static branching ref-counter
more than once. Today we call the whole memcg_update_kmem_limit()
function under the set_limit_mutex and this race is impossible.
As now we understand why the ACTIVATED bit was introduced and why we
don't need it now, and know that removing it will change nothing anyway,
let's get rid of it.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Glauber Costa <glommer@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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We relocate root cache's memcg_params whenever we need to grow the
memcg_caches array to accommodate all kmem-active memory cgroups.
Currently on relocation we free the old version immediately, which can
lead to use-after-free, because the memcg_caches array is accessed
lock-free (see cache_from_memcg_idx()). This patch fixes this by making
memcg_params RCU-protected for root caches.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Glauber Costa <glommer@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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There is no point in flooding logs with warnings or especially crashing
the system if we fail to create a cache for a memcg. In this case we
will be accounting the memcg allocation to the root cgroup until we
succeed to create its own cache, but it isn't that critical.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Glauber Costa <glommer@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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kmem_cache_dup() is only called from memcg_create_kmem_cache(). The
latter, in fact, does nothing besides this, so let's fold
kmem_cache_dup() into memcg_create_kmem_cache().
This patch also makes the memcg_cache_mutex private to
memcg_create_kmem_cache(), because it is not used anywhere else.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Glauber Costa <glommer@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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We obtain a per-memcg cache from a root kmem_cache by dereferencing an
entry of the root cache's memcg_params::memcg_caches array. If we find
no cache for a memcg there on allocation, we initiate the memcg cache
creation (see memcg_kmem_get_cache()). The cache creation proceeds
asynchronously in memcg_create_kmem_cache() in order to avoid lock
clashes, so there can be several threads trying to create the same
kmem_cache concurrently, but only one of them may succeed. However, due
to a race in the code, it is not always true. The point is that the
memcg_caches array can be relocated when we activate kmem accounting for
a memcg (see memcg_update_all_caches(), memcg_update_cache_size()). If
memcg_update_cache_size() and memcg_create_kmem_cache() proceed
concurrently as described below, we can leak a kmem_cache.
Asume two threads schedule creation of the same kmem_cache. One of them
successfully creates it. Another one should fail then, but if
memcg_create_kmem_cache() interleaves with memcg_update_cache_size() as
follows, it won't:
memcg_create_kmem_cache() memcg_update_cache_size()
(called w/o mutexes held) (called with slab_mutex,
set_limit_mutex held)
------------------------- -------------------------
mutex_lock(&memcg_cache_mutex)
s->memcg_params=kzalloc(...)
new_cachep=cache_from_memcg_idx(cachep,idx)
// new_cachep==NULL => proceed to creation
s->memcg_params->memcg_caches[i]
=cur_params->memcg_caches[i]
// kmem_cache_create_memcg takes slab_mutex
// so we will hang around until
// memcg_update_cache_size finishes, but
// nothing will prevent it from succeeding so
// memcg_caches[idx] will be overwritten in
// memcg_register_cache!
new_cachep = kmem_cache_create_memcg(...)
mutex_unlock(&memcg_cache_mutex)
Let's fix this by moving the check for existence of the memcg cache to
kmem_cache_create_memcg() to be called under the slab_mutex and make it
return NULL if so.
A similar race is possible when destroying a memcg cache (see
kmem_cache_destroy()). Since memcg_unregister_cache(), which clears the
pointer in the memcg_caches array, is called w/o protection, we can race
with memcg_update_cache_size() and omit clearing the pointer. Therefore
memcg_unregister_cache() should be moved before we release the
slab_mutex.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Glauber Costa <glommer@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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All caches of the same memory cgroup are linked in the memcg_slab_caches
list via kmem_cache::memcg_params::list. This list is traversed, for
example, when we read memory.kmem.slabinfo.
Since the list actually consists of memcg_cache_params objects, we have
to convert an element of the list to a kmem_cache object using
memcg_params_to_cache(), which obtains the pointer to the cache from the
memcg_params::memcg_caches array of the corresponding root cache. That
said the pointer to a kmem_cache in its parent's memcg_params must be
initialized before adding the cache to the list, and cleared only after
it has been unlinked. Currently it is vice-versa, which can result in a
NULL ptr dereference while traversing the memcg_slab_caches list. This
patch restores the correct order.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Glauber Costa <glommer@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Each root kmem_cache has pointers to per-memcg caches stored in its
memcg_params::memcg_caches array. Whenever we want to allocate a slab
for a memcg, we access this array to get per-memcg cache to allocate
from (see memcg_kmem_get_cache()). The access must be lock-free for
performance reasons, so we should use barriers to assert the kmem_cache
is up-to-date.
First, we should place a write barrier immediately before setting the
pointer to it in the memcg_caches array in order to make sure nobody
will see a partially initialized object. Second, we should issue a read
barrier before dereferencing the pointer to conform to the write
barrier.
However, currently the barrier usage looks rather strange. We have a
write barrier *after* setting the pointer and a read barrier *before*
reading the pointer, which is incorrect. This patch fixes this.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Glauber Costa <glommer@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Currently, we have rather a messy function set relating to per-memcg
kmem cache initialization/destruction.
Per-memcg caches are created in memcg_create_kmem_cache(). This
function calls kmem_cache_create_memcg() to allocate and initialize a
kmem cache and then "registers" the new cache in the
memcg_params::memcg_caches array of the parent cache.
During its work-flow, kmem_cache_create_memcg() executes the following
memcg-related functions:
- memcg_alloc_cache_params(), to initialize memcg_params of the newly
created cache;
- memcg_cache_list_add(), to add the new cache to the memcg_slab_caches
list.
On the other hand, kmem_cache_destroy() called on a cache destruction
only calls memcg_release_cache(), which does all the work: it cleans the
reference to the cache in its parent's memcg_params::memcg_caches,
removes the cache from the memcg_slab_caches list, and frees
memcg_params.
Such an inconsistency between destruction and initialization paths make
the code difficult to read, so let's clean this up a bit.
This patch moves all the code relating to registration of per-memcg
caches (adding to memcg list, setting the pointer to a cache from its
parent) to the newly created memcg_register_cache() and
memcg_unregister_cache() functions making the initialization and
destruction paths look symmetrical.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Glauber Costa <glommer@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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We do not free the cache's memcg_params if __kmem_cache_create fails.
Fix this.
Plus, rename memcg_register_cache() to memcg_alloc_cache_params(),
because it actually does not register the cache anywhere, but simply
initialize kmem_cache::memcg_params.
[akpm@linux-foundation.org: fix build]
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Glauber Costa <glommer@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Currently kmem_cache_create_memcg() backoffs on failure inside
conditionals, without using gotos. This results in the rollback code
duplication, which makes the function look cumbersome even though on
error we should only free the allocated cache. Since in the next patch
I am going to add yet another rollback function call on error path
there, let's employ labels instead of conditionals for undoing any
changes on failure to keep things clean.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Glauber Costa <glommer@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Most of the VM_BUG_ON assertions are performed on a page. Usually, when
one of these assertions fails we'll get a BUG_ON with a call stack and
the registers.
I've recently noticed based on the requests to add a small piece of code
that dumps the page to various VM_BUG_ON sites that the page dump is
quite useful to people debugging issues in mm.
This patch adds a VM_BUG_ON_PAGE(cond, page) which beyond doing what
VM_BUG_ON() does, also dumps the page before executing the actual
BUG_ON.
[akpm@linux-foundation.org: fix up includes]
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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stable_page_flags() checks !PageHuge && PageTransCompound && PageLRU to
know that a specified page is thp or not. But sometimes it's not enough
and we fail to detect thp when the thp is on pagevec. This happens only
for a few seconds after LRU list operations, but it makes it difficult
to control our applications depending on this flag.
So this patch adds another check PageAnon to detect thps on pagevec. It
might not give the future extensibility for thp pagecache, but it's OK
at least for now.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: David Rientjes <rientjes@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The vmalloc was introduced by 33327948782b ("memcgroup: use vmalloc for
mem_cgroup allocation"), because at that time MAX_NUMNODES was used for
defining the per-node array in the mem_cgroup structure so that the
structure could be huge even if the system had the only NUMA node.
The situation was significantly improved by commit 45cf7ebd5a03 ("memcg:
reduce the size of struct memcg 244-fold"), which made the size of the
mem_cgroup structure calculated dynamically depending on the real number
of NUMA nodes installed on the system (nr_node_ids), so now there is no
point in using vmalloc here: the structure is allocated rarely and on
most systems its size is about 1K.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Glauber Costa <glommer@openvz.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Since commit ff6a6da60b89 ("mm: accelerate munlock() treatment of THP
pages") munlock skips tail pages of a munlocked THP page. There is some
attempt to prevent bad consequences of racing with a THP page split, but
code inspection indicates that there are two problems that may lead to a
non-fatal, yet wrong outcome.
First, __split_huge_page_refcount() copies flags including PageMlocked
from the head page to the tail pages. Clearing PageMlocked by
munlock_vma_page() in the middle of this operation might result in part
of tail pages left with PageMlocked flag. As the head page still
appears to be a THP page until all tail pages are processed,
munlock_vma_page() might think it munlocked the whole THP page and skip
all the former tail pages. Before ff6a6da60, those pages would be
cleared in further iterations of munlock_vma_pages_range(), but NR_MLOCK
would still become undercounted (related the next point).
Second, NR_MLOCK accounting is based on call to hpage_nr_pages() after
the PageMlocked is cleared. The accounting might also become
inconsistent due to race with __split_huge_page_refcount()
- undercount when HUGE_PMD_NR is subtracted, but some tail pages are
left with PageMlocked set and counted again (only possible before
ff6a6da60)
- overcount when hpage_nr_pages() sees a normal page (split has already
finished), but the parallel split has meanwhile cleared PageMlocked from
additional tail pages
This patch prevents both problems via extending the scope of lru_lock in
munlock_vma_page(). This is convenient because:
- __split_huge_page_refcount() takes lru_lock for its whole operation
- munlock_vma_page() typically takes lru_lock anyway for page isolation
As this becomes a second function where page isolation is done with
lru_lock already held, factor this out to a new
__munlock_isolate_lru_page() function and clean up the code around.
[akpm@linux-foundation.org: avoid a coding-style ugly]
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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bad_page() is cool in that it prints out a bunch of data about the page.
But, I can never remember which page flags are good and which are bad,
or whether ->index or ->mapping is required to be NULL.
This patch allows bad/dump_page() callers to specify a string about why
they are dumping the page and adds explanation strings to a number of
places. It also adds a 'bad_flags' argument to bad_page(), which it
then dumps out separately from the flags which are actually set.
This way, the messages will show specifically why the page was bad,
*specifically* which flags it is complaining about, if it was a page
flag combination which was the problem.
[akpm@linux-foundation.org: switch to pr_alert]
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The "compressor" and "enabled" params are currently hidden, this changes
them to read-only, so userspace can tell if zswap is enabled or not and
see what compressor is in use.
Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Cc: Vladimir Murzin <murzin.v@gmail.com>
Cc: Bob Liu <bob.liu@oracle.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Weijie Yang <weijie.yang@samsung.com>
Acked-by: Seth Jennings <sjennings@variantweb.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Documentation/vm/locking is a blast from the past. In the entire git
history, it has had precisely Three modifications. Two of those look to
be pure renames, and the third was from 2005.
The doc contains such gems as:
> The page_table_lock is grabbed while holding the
> kernel_lock spinning monitor.
> Page stealers hold kernel_lock to protect against a bunch of
> races.
Or this which talks about mmap_sem:
> 4. The exception to this rule is expand_stack, which just
> takes the read lock and the page_table_lock, this is ok
> because it doesn't really modify fields anybody relies on.
expand_stack() doesn't take any locks any more directly, and the
mmap_sem acquisition was long ago moved up in to the page fault code
itself.
It could be argued that we need to rewrite this, but it is dangerous to
leave it as-is. It will confuse more people than it helps.
Signed-off-by: Dave Hansen <dave.hansen@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Sort the exception table at build-time rather than during boot.
Microblaze is the same case as AARCH64 that's why EM_MICROBLAZE
conditional check was added to allow cross-compilation on machines which
are not running the latest libc-dev.
Inspired by AARCH64 commit adace89562c7 ("arm64: extable: sort the
exception table at build time").
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Acked-by: David Daney <david.daney@cavium.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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drivers/staging/comedi/drivers/das6402.c: In function 'intr_handler':
drivers/staging/comedi/drivers/das6402.c:164:3: error: implicit declaration of function 'outw_p' [-Werror=implicit-function-declaration]
drivers/staging/speakup/speakup_dtlk.c: In function 'synth_probe':
drivers/staging/speakup/speakup_dtlk.c:362:2: error: implicit declaration of function 'inw_p' [-Werror=implicit-function-declaration]
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
Pull UDF & jbd fixes from Jan Kara:
"A cleanup of JBD log messages and UDF fix of a lockdep warning"
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
udf: Fix lockdep warning from udf_symlink()
jbd: Revise KERN_EMERG error messages
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Lockdep is complaining about UDF:
=============================================
[ INFO: possible recursive locking detected ]
3.12.0+ #16 Not tainted
---------------------------------------------
ln/7386 is trying to acquire lock:
(&ei->i_data_sem){+.+...}, at: [<ffffffff8142f06d>] udf_get_block+0x8d/0x130
but task is already holding lock:
(&ei->i_data_sem){+.+...}, at: [<ffffffff81431a8d>] udf_symlink+0x8d/0x690
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&ei->i_data_sem);
lock(&ei->i_data_sem);
*** DEADLOCK ***
This is because we hold i_data_sem of the symlink inode while calling
udf_add_entry() for the directory. I don't think this can ever lead to
deadlocks since we never hold i_data_sem for two inodes in any other
place.
The fix is simple - move unlock of i_data_sem for symlink inode up. We
don't need it for anything when linking symlink inode to directory.
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jan Kara <jack@suse.cz>
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Some of KERN_EMERG printk messages do not really deserve this log level
and the one in log_wait_commit() is even rather useless (the journal has
been previously aborted and *that* is where we should have been
complaining). So make some messages just KERN_ERR and remove the useless
message.
Signed-off-by: Jan Kara <jack@suse.cz>
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The associative array code creates unnecessary and potentially
problematic global variable 'status'. Remove it since never used.
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse
Pull fuse update from Miklos Szeredi:
"This contains a fix for a potential use-after-module-unload bug
noticed by Al and caching improvements for read-only fuse filesystems
by Andrew Gallagher"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
fuse: support clients that don't implement 'open'
fuse: don't invalidate attrs when not using atime
fuse: fix SetPageUptodate() condition in STORE
fuse: fix pipe_buf_operations
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open/release operations require userspace transitions to keep track
of the open count and to perform any FS-specific setup. However,
for some purely read-only FSs which don't need to perform any setup
at open/release time, we can avoid the performance overhead of
calling into userspace for open/release calls.
This patch adds the necessary support to the fuse kernel modules to prevent
open/release operations from hitting in userspace. When the client returns
ENOSYS, we avoid sending the subsequent release to userspace, and also
remember this so that future opens also don't trigger a userspace
operation.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
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Various read operations (e.g. readlink, readdir) invalidate the cached
attrs for atime changes. This patch adds a new function
'fuse_invalidate_atime', which checks for a read-only super block and
avoids the attr invalidation in that case.
Signed-off-by: Andrew Gallagher <andrewjcg@fb.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
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As noticed by Coverity the "num != 0" condition never triggers. Instead it
should check for a complete page.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
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Having this struct in module memory could Oops when if the module is
unloaded while the buffer still persists in a pipe.
Since sock_pipe_buf_ops is essentially the same as fuse_dev_pipe_buf_steal
merge them into nosteal_pipe_buf_ops (this is the same as
default_pipe_buf_ops except stealing the page from the buffer is not
allowed).
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: stable@vger.kernel.org
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git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs
Pull f2fs updates from Jaegeuk Kim:
"In this round, a couple of sysfs entries were introduced to tune the
f2fs at runtime.
In addition, f2fs starts to support inline_data and improves the
read/write performance in some workloads by refactoring bio-related
flows.
This patch-set includes the following major enhancement patches.
- support inline_data
- refactor bio operations such as merge operations and rw type
assignment
- enhance the direct IO path
- enhance bio operations
- truncate a node page when it becomes obsolete
- add sysfs entries: small_discards, max_victim_search, and
in-place-update
- add a sysfs entry to control max_victim_search
The other bug fixes are as follows.
- fix a bug in truncate_partial_nodes
- avoid warnings during sparse and build process
- fix error handling flows
- fix potential bit overflows
And, there are a bunch of cleanups"
* tag 'for-f2fs-3.14' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (95 commits)
f2fs: drop obsolete node page when it is truncated
f2fs: introduce NODE_MAPPING for code consistency
f2fs: remove the orphan block page array
f2fs: add help function META_MAPPING
f2fs: move a branch for code redability
f2fs: call mark_inode_dirty to flush dirty pages
f2fs: clean checkpatch warnings
f2fs: missing REQ_META and REQ_PRIO when sync_meta_pages(META_FLUSH)
f2fs: avoid f2fs_balance_fs call during pageout
f2fs: add delimiter to seperate name and value in debug phrase
f2fs: use spinlock rather than mutex for better speed
f2fs: move alloc new orphan node out of lock protection region
f2fs: move grabing orphan pages out of protection region
f2fs: remove the needless parameter of f2fs_wait_on_page_writeback
f2fs: update documents and a MAINTAINERS entry
f2fs: add a sysfs entry to control max_victim_search
f2fs: improve write performance under frequent fsync calls
f2fs: avoid to read inline data except first page
f2fs: avoid to left uninitialized data in page when read inline data
f2fs: fix truncate_partial_nodes bug
...
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If a node page is trucated, we'd better drop the page in the node_inode's page
cache for better memory footprint.
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
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This patch adds NODE_MAPPING which is similar as META_MAPPING introduced by
Gu Zheng.
Cc: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
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As the orphan_blocks may be max to 504, so it is not security
and rigorous to store such a large array in the kernel stack
as Dan Carpenter said.
In fact, grab_meta_page has locked the page in the page cache,
and we can use find_get_page() to fetch the page safely in the
downstream, so we can remove the page array directly.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
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Introduce help function META_MAPPING() to get the cache meta blocks'
address space.
Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
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This patch moves a function in f2fs_delete_entry for code readability.
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
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If a dentry page is updated, we should call mark_inode_dirty to add the inode
into the dirty list, so that its dentry pages are flushed to the disk.
Otherwise, the inode can be evicted without flush.
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
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Fixed a variety of trivial checkpatch warnings. The only delta should
be some minor formatting on log strings that were split / too long.
Signed-off-by: Chris Fries <cfries@motorola.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
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Doing sync_meta_pages with META_FLUSH when checkpoint, we overide rw
using WRITE_FLUSH_FUA. At this time, we also should set
REQ_META|REQ_PRIO.
Signed-off-by: Changman Lee <cm224.lee@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
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This patch should resolve the following bug.
=========================================================
[ INFO: possible irq lock inversion dependency detected ]
3.13.0-rc5.f2fs+ #6 Not tainted
---------------------------------------------------------
kswapd0/41 just changed the state of lock:
(&sbi->gc_mutex){+.+.-.}, at: [<ffffffffa030503e>] f2fs_balance_fs+0xae/0xd0 [f2fs]
but this lock took another, RECLAIM_FS-READ-unsafe lock in the past:
(&sbi->cp_rwsem){++++.?}
and interrupts could create inverse lock ordering between them.
other info that might help us debug this:
Chain exists of:
&sbi->gc_mutex --> &sbi->cp_mutex --> &sbi->cp_rwsem
Possible interrupt unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&sbi->cp_rwsem);
local_irq_disable();
lock(&sbi->gc_mutex);
lock(&sbi->cp_mutex);
<Interrupt>
lock(&sbi->gc_mutex);
*** DEADLOCK ***
This bug is due to the f2fs_balance_fs call in f2fs_write_data_page.
If f2fs_write_data_page is triggered by wbc->for_reclaim via kswapd, it should
not call f2fs_balance_fs which tries to get a mutex grabbed by original syscall
flow.
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
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Support for f2fs-tools/tools/f2stat to monitor
/sys/kernel/debug/f2fs/status
Signed-off-by: Changman Lee <cm224.lee@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
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With the 2 previous changes, all the long time operations are moved out
of the protection region, so here we can use spinlock rather than mutex
(orphan_inode_mutex) for lower overhead.
Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
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Move alloc new orphan node out of lock protection region.
Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
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Move grabing orphan block page out of protection region, and grab all
the orphan block pages ahead.
Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Reviewed-by: Chao Yu <chao2.yu@samsung.com>
[Jaegeuk Kim: remove unnecessary code pointed by Chao Yu]
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
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"boo sync" parameter is never referenced in f2fs_wait_on_page_writeback.
We should remove this parameter.
Signed-off-by: Yuan Zhong <yuan.mark.zhong@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
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This patch adds missing some description of sysfs entries in
- Documentation/ABI/testing/sysfs-fs-f2fs
- Documentation/filesystems/f2fs.txt.
And it adds a maintained document entry of F2FS in MAINTAINERS.
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
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Previously during SSR and GC, the maximum number of retrials to find a victim
segment was hard-coded by MAX_VICTIM_SEARCH, 4096 by default.
This number makes an effect on IO locality, when SSR mode is activated, which
results in performance fluctuation on some low-end devices.
If max_victim_search = 4, the victim will be searched like below.
("D" represents a dirty segment, and "*" indicates a selected victim segment.)
D1 D2 D3 D4 D5 D6 D7 D8 D9
[ * ]
[ * ]
[ * ]
[ ....]
This patch adds a sysfs entry to control the number dynamically through:
/sys/fs/f2fs/$dev/max_victim_search
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
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When considering a bunch of data writes with very frequent fsync calls, we
are able to think the following performance regression.
N: Node IO, D: Data IO, IO scheduler: cfq
Issue pending IOs
D1 D2 D3 D4
D1 D2 D3 D4 N1
D2 D3 D4 N1 N2
N1 D3 D4 N2 D1
--> N1 can be selected by cfq becase of the same priority of N and D.
Then D3 and D4 would be delayed, resuling in performance degradation.
So, when processing the fsync call, it'd better give higher priority to data IOs
than node IOs by assigning WRITE and WRITE_SYNC respectively.
This patch improves the random wirte performance with frequent fsync calls by up
to 10%.
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
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