- 07 Aug, 2014 40 commits
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Johannes Weiner authored
Kmem page charging and uncharging is serialized by means of exclusive access to the page. Do not take the page_cgroup lock and don't set pc->flags atomically. Signed-off-by:
Johannes Weiner <hannes@cmpxchg.org> Acked-by:
Michal Hocko <mhocko@suse.cz> Acked-by:
Vladimir Davydov <vdavydov@parallels.com> Cc: Hugh Dickins <hughd@google.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Johannes Weiner authored
There is a write barrier between setting pc->mem_cgroup and PageCgroupUsed, which was added to allow LRU operations to lookup the memcg LRU list of a page without acquiring the page_cgroup lock. But ever since commit 38c5d72f ("memcg: simplify LRU handling by new rule"), pages are ensured to be off-LRU while charging, so nobody else is changing LRU state while pc->mem_cgroup is being written, and there are no read barriers anymore. Remove the unnecessary write barrier. Signed-off-by:
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Johannes Weiner authored
Due to an old optimization to keep expensive res_counter changes at a minimum, the root_mem_cgroup res_counter is never charged; there is no limit at that level anyway, and any statistics can be generated on demand by summing up the counters of all other cgroups. However, with per-cpu charge caches, res_counter operations do not even show up in profiles anymore, so this optimization is no longer necessary. Remove it to simplify the code. Signed-off-by:
Michal Hocko <mhocko@suse.com> Cc: Hugh Dickins <hughd@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vladimir Davydov <vdavydov@parallels.com> Signed-off-by:
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Johannes Weiner authored
When mem_cgroup_try_charge() returns -EINTR, it bypassed the charge to the root memcg. But move precharging does not catch this and treats this case as if no charge had happened, thus leaking a charge against root. Because of an old optimization, the root memcg's res_counter is not actually charged right now, but it's still an imbalance and subsequent patches will charge the root memcg again. Catch those bypasses to the root memcg and properly cancel them before giving up the move. Signed-off-by:
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Johannes Weiner authored
The move precharge function does some baroque things: it tries raw res_counter charging of the entire amount first, and then falls back to a loop of one-by-one charges, with checks for pending signals and cond_resched() batching. Just use mem_cgroup_try_charge() without __GFP_WAIT for the first bulk charge attempt. In the one-by-one loop, remove the signal check (this is already checked in try_charge), and simply call cond_resched() after every charge - it's not that expensive. Signed-off-by:
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Michal Hocko authored
For the page allocator, __GFP_NORETRY implies that no OOM should be triggered, whereas memcg has an explicit parameter to disable OOM. The only callsites that want OOM disabled are THP charges and charge moving. THP already uses __GFP_NORETRY and charge moving can use it as well - one full reclaim cycle should be plenty. Switch it over, then remove the OOM parameter. Signed-off-by:
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Johannes Weiner authored
There is no reason why oom-disabled and __GFP_NOFAIL charges should try to reclaim only once when every other charge tries several times before giving up. Make them all retry the same number of times. Signed-off-by:
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Johannes Weiner authored
Transparent huge page charges prefer falling back to regular pages rather than spending a lot of time in direct reclaim. Desired reclaim behavior is usually declared in the gfp mask, but THP charges use GFP_KERNEL and then rely on the fact that OOM is disabled for THP charges, and that OOM-disabled charges don't retry reclaim. Needless to say, this is anything but obvious and quite error prone. Convert THP charges to use GFP_TRANSHUGE instead, which implies __GFP_NORETRY, to indicate the low-latency requirement. Signed-off-by:
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Johannes Weiner authored
Currently, __GFP_NORETRY tries charging once and gives up before even trying to reclaim. Bring the behavior on par with the page allocator and reclaim at least once before giving up. Signed-off-by:
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Johannes Weiner authored
The charging path currently starts out with OOM condition checks when OOM is the rarest possible case. Rearrange this code to run OOM/task dying checks only after trying the percpu charge and the res_counter charge and bail out before entering reclaim. Attempting a charge does not hurt an (oom-)killed task as much as every charge attempt having to check OOM conditions. Also, only check __GFP_NOFAIL when the charge would actually fail. Signed-off-by:
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Johannes Weiner authored
These patches rework memcg charge lifetime to integrate more naturally with the lifetime of user pages. This drastically simplifies the code and reduces charging and uncharging overhead. The most expensive part of charging and uncharging is the page_cgroup bit spinlock, which is removed entirely after this series. Here are the top-10 profile entries of a stress test that reads a 128G sparse file on a freshly booted box, without even a dedicated cgroup (i.e. executing in the root memcg). Before: 15.36% cat [kernel.kallsyms] [k] copy_user_generic_string 13.31% cat [kernel.kallsyms] [k] memset 11.48% cat [kernel.kallsyms] [k] do_mpage_readpage 4.23% cat [kernel.kallsyms] [k] get_page_from_freelist 2.38% cat [kernel.kallsyms] [k] put_page 2.32% cat [kernel.kallsyms] [k] __mem_cgroup_commit_charge 2.18% kswapd0 [kernel.kallsyms] [k] __mem_cgroup_uncharge_common 1.92% kswapd0 [kernel.kallsyms] [k] shrink_page_list 1.86% cat [kernel.kallsyms] [k] __radix_tree_lookup 1.62% cat [kernel.kallsyms] [k] __pagevec_lru_add_fn After: 15.67% cat [kernel.kallsyms] [k] copy_user_generic_string 13.48% cat [kernel.kallsyms] [k] memset 11.42% cat [kernel.kallsyms] [k] do_mpage_readpage 3.98% cat [kernel.kallsyms] [k] get_page_from_freelist 2.46% cat [kernel.kallsyms] [k] put_page 2.13% kswapd0 [kernel.kallsyms] [k] shrink_page_list 1.88% cat [kernel.kallsyms] [k] __radix_tree_lookup 1.67% cat [kernel.kallsyms] [k] __pagevec_lru_add_fn 1.39% kswapd0 [kernel.kallsyms] [k] free_pcppages_bulk 1.30% cat [kernel.kallsyms] [k] kfree As you can see, the memcg footprint has shrunk quite a bit. text data bss dec hex filename 37970 9892 400 48262 bc86 mm/memcontrol.o.old 35239 9892 400 45531 b1db mm/memcontrol.o This patch (of 13): This function was split out because mem_cgroup_try_charge() got too big. But having essentially one sequence of operations arbitrarily split in half is not good for reworking the code. Fold it back in. Signed-off-by: -
Johannes Weiner authored
- PAGEFLAG_FALSE only defines TEST, make it define SET and CLEAR as well, analogous to PAGEFLAG. - Define TESTSETFLAG_FALSE, analogous to TESTSETFLAG. - Define TESTSCFLAG_FALSE, analogous to TESTSCFLAG - Make PG_mlocked accessors the same on both MMU and !MMU setups Signed-off-by:
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Waiman Long authored
In some architectures like x86, atomic_add() is a full memory barrier. In that case, an additional smp_mb() is just a waste of time. This patch replaces that smp_mb() by smp_mb__after_atomic() which will avoid the redundant memory barrier in some architectures. With a 3.16-rc1 based kernel, this patch reduced the execution time of breaking 1000 transparent huge pages from 38,245us to 30,964us. A reduction of 19% which is quite sizeable. It also reduces the %cpu time of the __split_huge_page_refcount function in the perf profile from 2.18% to 1.15%. 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:
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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:
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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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