- 07 Aug, 2014 40 commits
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Waiman Long authored
In __split_huge_page_map(), the check for page_mapcount(page) is invariant within the for loop. Because of the fact that the macro is implemented using atomic_read(), the redundant check cannot be optimized away by the compiler leading to unnecessary read to the page structure. This patch moves the invariant bug check out of the loop so that it will be done only once. On a 3.16-rc1 based kernel, the execution time of a microbenchmark that broke up 1000 transparent huge pages using munmap() had an execution time of 38,245us and 38,548us with and without the patch respectively. The performance gain is about 1%. Signed-off-by:
Waiman Long <Waiman.Long@hp.com> Acked-by:
Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Scott J Norton <scott.norton@hp.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Joonsoo Kim authored
We don't need explicit 'CMA:' prefix, since we already define prefix 'cma:' in pr_fmt. So remove it. Signed-off-by:
Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by:
Michal Nazarewicz <mina86@mina86.com> Reviewed-by:
Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Alexander Graf <agraf@suse.de> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Gleb Natapov <gleb@kernel.org> Acked-by:
Marek Szyprowski <m.szyprowski@samsung.com> Tested-by:
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Joonsoo Kim authored
Conventionally, we put output param to the end of param list and put the 'base' ahead of 'size', but cma_declare_contiguous() doesn't look like that, so change it. Additionally, move down cma_areas reference code to the position where it is really needed. Signed-off-by:
Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Alexander Graf <agraf@suse.de> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Gleb Natapov <gleb@kernel.org> Acked-by:
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Joonsoo Kim authored
We can remove one call sites for clear_cma_bitmap() if we first call it before checking error number. Signed-off-by:
Minchan Kim <minchan@kernel.org> Reviewed-by:
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Joonsoo Kim authored
Now, we have general CMA reserved area management framework, so use it for future maintainabilty. There is no functional change. Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com> Tested-by:
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Joonsoo Kim authored
Currently, there are two users on CMA functionality, one is the DMA subsystem and the other is the KVM on powerpc. They have their own code to manage CMA reserved area even if they looks really similar. From my guess, it is caused by some needs on bitmap management. KVM side wants to maintain bitmap not for 1 page, but for more size. Eventually it use bitmap where one bit represents 64 pages. When I implement CMA related patches, I should change those two places to apply my change and it seem to be painful to me. I want to change this situation and reduce future code management overhead through this patch. This change could also help developer who want to use CMA in their new feature development, since they can use CMA easily without copying & pasting this reserved area management code. In previous patches, we have prepared some features to generalize CMA reserved area management and now it's time to do it. This patch moves core functions to mm/cma.c and change DMA APIs to use these functions. There is no functional change in DMA APIs. Signed-off-by:
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Joonsoo Kim authored
PPC KVM's CMA area management requires arbitrary bitmap granularity, since they want to reserve very large memory and manage this region with bitmap that one bit for several pages to reduce management overheads. So support arbitrary bitmap granularity for following generalization. [akpm@linux-foundation.org: s/1/1UL/] Signed-off-by:
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Joonsoo Kim authored
PPC KVM's CMA area management needs alignment constraint on CMA region. So support it to prepare generalization of CMA area management functionality. Additionally, add some comments which tell us why alignment constraint is needed on CMA region. Signed-off-by:
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Joonsoo Kim authored
To prepare future generalization work on CMA area management code, we need to separate core CMA management codes from DMA APIs. We will extend these core functions to cover requirements of PPC KVM's CMA area management functionality in following patches. This separation helps us not to touch DMA APIs while extending core functions. Signed-off-by:
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Fabian Frederick authored
Use nth_page instead of pfn_to_page(page_to_pfn Signed-off-by:
Fabian Frederick <fabf@skynet.be> Cc: Rik van Riel <riel@redhat.com> Signed-off-by:
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Michal Nazarewicz authored
Instead of open-coding getting minimal value of two, just use min macro. That is why it is there for. While changing the function also change type of batch local variable to match type of per_cpu_pages::batch (which is int). Signed-off-by:
David Rientjes <rientjes@google.com> Signed-off-by:
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Tang Chen authored
In store_mem_state(), we have: ... 334 else if (!strncmp(buf, "offline", min_t(int, count, 7))) 335 online_type = -1; ... 355 case -1: 356 ret = device_offline(&mem->dev); 357 break; ... Here, "offline" is hard coded as -1. This patch does the following renaming: ONLINE_KEEP -> MMOP_ONLINE_KEEP ONLINE_KERNEL -> MMOP_ONLINE_KERNEL ONLINE_MOVABLE -> MMOP_ONLINE_MOVABLE and introduces MMOP_OFFLINE = -1 to avoid hard coding. Signed-off-by:
Tang Chen <tangchen@cn.fujitsu.com> Cc: Hu Tao <hutao@cn.fujitsu.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Gu Zheng <guz.fnst@cn.fujitsu.com> Signed-off-by:
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Tang Chen authored
We use the following command to online a memory_block: echo online|online_kernel|online_movable > /sys/devices/system/memory/memoryXXX/state But, if we do the following: echo online_fhsjkghfkd > /sys/devices/system/memory/memoryXXX/state the block will also be onlined. This is because the following code in store_mem_state() does not compare the whole string, but only the prefix of the string. store_mem_state() { ...... 328 if (!strncmp(buf, "online_kernel", min_t(int, count, 13))) Here, only compare the first 13 letters of the string. If we give "online_kernelXXXXXX", it will be recognized as online_kernel, which is incorrect. 329 online_type = ONLINE_KERNEL; 330 else if (!strncmp(buf, "online_movable", min_t(int, count, 14))) We have the same problem here, 331 online_type = ONLINE_MOVABLE; 332 else if (!strncmp(buf, "online", min_t(int, count, 6))) here, (Here is more problematic. If we give online_movalbe, which is a typo of online_movable, it will be recognized as online without noticing the author.) 333 online_type = ONLINE_KEEP; 334 else if (!strncmp(buf, "offline", min_t(int, count, 7))) and here. 335 online_type = -1; 336 else { 337 ret = -EINVAL; 338 goto err; 339 } ...... } This patch fixes this problem by using sysfs_streq() to compare the whole string. Signed-off-by:Hu Tao <hutao@cn.fujitsu.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Gu Zheng <guz.fnst@cn.fujitsu.com> Acked-by:
Toshi Kani <toshi.kani@hp.com> Signed-off-by:
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Hugh Dickins authored
Use ACCESS_ONCE() in handle_pte_fault() when getting the entry or orig_pte upon which all subsequent decisions and pte_same() tests will be made. I have no evidence that its lack is responsible for the mm/filemap.c:202 BUG_ON(page_mapped(page)) in __delete_from_page_cache() found by trinity, and I am not optimistic that it will fix it. But I have found no other explanation, and ACCESS_ONCE() here will surely not hurt. If gcc does re-access the pte before passing it down, then that would be disastrous for correct page fault handling, and certainly could explain the page_mapped() BUGs seen (concurrent fault causing page to be mapped in a second time on top of itself: mapcount 2 for a single pte). Signed-off-by:
Hugh Dickins <hughd@google.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Signed-off-by:
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Joonsoo Kim authored
Richard Yao reported a month ago that his system have a trouble with vmap_area_lock contention during performance analysis by /proc/meminfo. Andrew asked why his analysis checks /proc/meminfo stressfully, but he didn't answer it. https://lkml.org/lkml/2014/4/10/416 Although I'm not sure that this is right usage or not, there is a solution reducing vmap_area_lock contention with no side-effect. That is just to use rcu list iterator in get_vmalloc_info(). rcu can be used in this function because all RCU protocol is already respected by writers, since Nick Piggin commit db64fe02 ("mm: rewrite vmap layer") back in linux-2.6.28 Specifically : insertions use list_add_rcu(), deletions use list_del_rcu() and kfree_rcu(). Note the rb tree is not used from rcu reader (it would not be safe), only the vmap_area_list has full RCU protection. Note that __purge_vmap_area_lazy() already uses this rcu protection. rcu_read_lock(); list_for_each_entry_rcu(va, &vmap_area_list, list) { if (va->flags & VM_LAZY_FREE) { if (va->va_start < *start) *start = va->va_start; if (va->va_end > *end) *end = va->va_end; nr += (va->va_end - va->va_start) >> PAGE_SHIFT; list_add_tail(&va->purge_list, &valist); va->flags |= VM_LAZY_FREEING; va->flags &= ~VM_LAZY_FREE; } } rcu_read_unlock(); Peter: : While rcu list traversal over the vmap_area_list is safe, this may : arrive at different results than the spinlocked version. The rcu list : traversal version will not be a 'snapshot' of a single, valid instant : of the entire vmap_area_list, but rather a potential amalgam of : different list states. Joonsoo: : Yes, you are right, but I don't think that we should be strict here. : Meminfo is already not a 'snapshot' at specific time. While we try to get : certain stats, the other stats can change. And, although we may arrive at : different results than the spinlocked version, the difference would not be : large and would not make serious side-effect. [edumazet@google.com: add more commit description] Signed-off-by:
Richard Yao <ryao@gentoo.org> Acked-by:
Eric Dumazet <edumazet@google.com> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: Zhang Yanfei <zhangyanfei.yes@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Andi Kleen <andi@firstfloor.org> Signed-off-by:
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Fabian Frederick authored
memblock_set_bottom_up() is only called by __init cmdline_parse_movable_node() and __init numa_init(). Signed-off-by:
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Andrew Morton authored
It is only called by mm/page_cgroup.c whcih cannot be modular. Reported-by:
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Fabian Frederick authored
alloc_pages_exact_nid() is only called by __meminit alloc_page_cgroup() Signed-off-by:
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Fabian Frederick authored
grow_zone_span and grow_pgdat_span are only called by __meminit __add_zone Signed-off-by:
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Fabian Frederick authored
count_history_pages does only call page_cache_prev_hole in rcu_lock context using address_space mapping. There's no need to have file_ra_state here. Signed-off-by:
Fengguang Wu <fengguang.wu@intel.com> Acked-by:
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Joe Perches authored
Just about all of these have been converted to __func__, so convert the last use. Signed-off-by:
Joe Perches <joe@perches.com> Signed-off-by:
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Gu Zheng authored
We mark some slab caches (e.g. kmem_cache_node) as unmergeable by setting refcount to -1, and their alias should be 0, not refcount-1, so correct it here. Signed-off-by:
Gu Zheng <guz.fnst@cn.fujitsu.com> Acked-by:
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Dan Carpenter authored
The return statement goes with the cmpxchg_double() condition so it needs to be indented another tab. Also these days the fashion is to line function parameters up, and it looks nicer that way because then the "freelist_new" is not at the same indent level as the "return 1;". Signed-off-by:
Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by:
Pekka Enberg <penberg@kernel.org> Signed-off-by:
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Wang Sheng-Hui authored
Current struct kmem_cache has no 'lock' field, and slab page is managed by struct kmem_cache_node, which has 'list_lock' field. Clean up the related comment. Signed-off-by:
Wang Sheng-Hui <shhuiw@gmail.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by:
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Andrey Ryabinin authored
Functions krealloc(), __krealloc(), kzfree() belongs to slab API, so should be placed in slab_common.c Also move slab allocator's tracepoints defenitions to slab_common.c No functional changes here. Signed-off-by:
Andrey Ryabinin <a.ryabinin@samsung.com> Acked-by:
Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by:
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Wei Yang authored
When a kmem_cache is created with ctor, each object in the kmem_cache will be initialized before ready to use. While in slub implementation, the first object will be initialized twice. This patch reduces the duplication of initialization of the first object. Fix commit 7656c72b ("SLUB: add macros for scanning objects in a slab"). Signed-off-by:
Wei Yang <weiyang@linux.vnet.ibm.com> Acked-by:
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Joonsoo Kim authored
It is better to represent allocation size in size_t rather than int. So change it. Signed-off-by:
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Joonsoo Kim authored
BAD_ALIEN_MAGIC value isn't used anymore. So remove it. Signed-off-by:
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Joonsoo Kim authored
Now, there is no code to hold two lock simultaneously, since we don't call slab_destroy() with holding any lock. So, lockdep annotation is useless now. Remove it. v2: don't remove BAD_ALIEN_MAGIC in this patch. It will be removed in the following patch. Signed-off-by: -
Joonsoo Kim authored
I haven't heard that this alien cache lock is contended, but to reduce chance of contention would be better generally. And with this change, we can simplify complex lockdep annotation in slab code. In the following patch, it will be implemented. Signed-off-by:
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Joonsoo Kim authored
Now, we have separate alien_cache structure, so it'd be better to hold the lock on alien_cache while manipulating alien_cache. After that, we don't need the lock on array_cache, so remove it. Signed-off-by:
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Joonsoo Kim authored
Currently, we use array_cache for alien_cache. Although they are mostly similar, there is one difference, that is, need for spinlock. We don't need spinlock for array_cache itself, but to use array_cache for alien_cache, array_cache structure should have spinlock. This is needless overhead, so removing it would be better. This patch prepare it by introducing alien_cache and using it. In the following patch, we remove spinlock in array_cache. Signed-off-by:
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Joonsoo Kim authored
Factor out initialization of array cache to use it in following patch. Signed-off-by:
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Joonsoo Kim authored
In free_block(), if freeing object makes new free slab and number of free_objects exceeds free_limit, we start to destroy this new free slab with holding the kmem_cache node lock. Holding the lock is useless and, generally, holding a lock as least as possible is good thing. I never measure performance effect of this, but we'd be better not to hold the lock as much as possible. Commented by Christoph: This is also good because kmem_cache_free is no longer called while holding the node lock. So we avoid one case of recursion. Signed-off-by:
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Joonsoo Kim authored
node isn't changed, so we don't need to retreive this structure everytime we move the object. Maybe compiler do this optimization, but making it explicitly is better. Signed-off-by:
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Joonsoo Kim authored
This patchset does some cleanup and tries to remove lockdep annotation. Patches 1~2 are just for really really minor improvement. Patches 3~9 are for clean-up and removing lockdep annotation. There are two cases that lockdep annotation is needed in SLAB. 1) holding two node locks 2) holding two array cache(alien cache) locks I looked at the code and found that we can avoid these cases without any negative effect. 1) occurs if freeing object makes new free slab and we decide to destroy it. Although we don't need to hold the lock during destroying a slab, current code do that. Destroying a slab without holding the lock would help the reduction of the lock contention. To do it, I change the implementation that new free slab is destroyed after releasing the lock. 2) occurs on similar situation. When we free object from non-local node, we put this object to alien cache with holding the alien cache lock. If alien cache is full, we try to flush alien cache to proper node cache, and, in this time, new free slab could be made. Destroying it would be started and we will free metadata object which comes from another node. In this case, we need another node's alien cache lock to free object. This forces us to hold two array cache locks and then we need lockdep annotation although they are always different locks and deadlock cannot be possible. To prevent this situation, I use same way as 1). In this way, we can avoid 1) and 2) cases, and then, can remove lockdep annotation. As short stat noted, this makes SLAB code much simpler. This patch (of 9): slab_should_failslab() is called on every allocation, so to optimize it is reasonable. We normally don't allocate from kmem_cache. It is just used when new kmem_cache is created, so it's very rare case. Therefore, add unlikely macro to help compiler optimization. Signed-off-by:
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Andrey Ryabinin authored
There are two versions of alloc/free hooks now - one for CONFIG_SLUB_DEBUG=y and another one for CONFIG_SLUB_DEBUG=n. I see no reason why calls to other debugging subsystems (LOCKDEP, DEBUG_ATOMIC_SLEEP, KMEMCHECK and FAILSLAB) are hidden under SLUB_DEBUG. All this features should work regardless of SLUB_DEBUG config, as all of them already have own Kconfig options. This also fixes failslab for CONFIG_SLUB_DEBUG=n configuration. It simply has not worked before because should_failslab() call was in a hook hidden under "#ifdef CONFIG_SLUB_DEBUG #else". Note: There is one concealed change in allocation path for SLUB_DEBUG=n and all other debugging features disabled. The might_sleep_if() call can generate some code even if DEBUG_ATOMIC_SLEEP=n. For PREEMPT_VOLUNTARY=y might_sleep() inserts _cond_resched() call, but I think it should be ok. Signed-off-by:
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David Rientjes authored
resiliency_test() is only called for bootstrap, so it may be moved to init.text and freed after boot. Signed-off-by:
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Andrey Ryabinin authored
Guarding section: #ifndef MM_SLAB_H #define MM_SLAB_H ... #endif currently doesn't cover the whole mm/slab.h. It seems like it was done unintentionally. Wrap the whole file by moving closing #endif to the end of it. Signed-off-by:
Vladimir Davydov <vdavydov@parallels.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by:
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Christoph Lameter authored
Use the two functions to simplify the code avoiding numerous explicit checks coded checking for a certain node to be online. Get rid of various repeated calculations of kmem_cache_node structures. [akpm@linux-foundation.org: fix build] Signed-off-by:
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