- 18 7月, 2007 18 次提交
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由 Christoph Lameter 提交于
The objects per slab increase with the current patches in mm since we allow up to order 3 allocs by default. More patches in mm actually allow to use 2M or higher sized slabs. For slab validation we need per object bitmaps in order to check a slab. We end up with up to 64k objects per slab resulting in a potential requirement of 8K stack space. That does not look good. Allocate the bit arrays via kmalloc. Signed-off-by: NChristoph Lameter <clameter@sgi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Christoph Lameter 提交于
It becomes now easy to support the zeroing allocs with generic inline functions in slab.h. Provide inline definitions to allow the continued use of kzalloc, kmem_cache_zalloc etc but remove other definitions of zeroing functions from the slab allocators and util.c. Signed-off-by: NChristoph Lameter <clameter@sgi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Christoph Lameter 提交于
We can get to the length of the object through the kmem_cache_structure. The additional parameter does no good and causes the compiler to generate bad code. Signed-off-by: NChristoph Lameter <clameter@sgi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Christoph Lameter 提交于
Do proper spacing and we only need to do this in steps of 8. Signed-off-by: NChristoph Lameter <clameter@sgi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Adrian Bunk 提交于
Signed-off-by: NAdrian Bunk <bunk@stusta.de> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Christoph Lameter 提交于
There is no need to caculate the dma slab size ourselves. We can simply lookup the size of the corresponding non dma slab. Signed-off-by: NChristoph Lameter <clameter@sgi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Christoph Lameter 提交于
kmalloc_index is a long series of comparisons. The attempt to replace kmalloc_index with something more efficient like ilog2 failed due to compiler issues with constant folding on gcc 3.3 / powerpc. kmalloc_index()'es long list of comparisons works fine for constant folding since all the comparisons are optimized away. However, SLUB also uses kmalloc_index to determine the slab to use for the __kmalloc_xxx functions. This leads to a large set of comparisons in get_slab(). The patch here allows to get rid of that list of comparisons in get_slab(): 1. If the requested size is larger than 192 then we can simply use fls to determine the slab index since all larger slabs are of the power of two type. 2. If the requested size is smaller then we cannot use fls since there are non power of two caches to be considered. However, the sizes are in a managable range. So we divide the size by 8. Then we have only 24 possibilities left and then we simply look up the kmalloc index in a table. Code size of slub.o decreases by more than 200 bytes through this patch. Signed-off-by: NChristoph Lameter <clameter@sgi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Christoph Lameter 提交于
We modify the kmalloc_cache_dma[] array without proper locking. Do the proper locking and undo the dma cache creation if another processor has already created it. Signed-off-by: NChristoph Lameter <clameter@sgi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Christoph Lameter 提交于
The rarely used dma functionality in get_slab() makes the function too complex. The compiler begins to spill variables from the working set onto the stack. The created function is only used in extremely rare cases so make sure that the compiler does not decide on its own to merge it back into get_slab(). Signed-off-by: NChristoph Lameter <clameter@sgi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Christoph Lameter 提交于
Add #ifdefs around data structures only needed if debugging is compiled into SLUB. Add inlines to small functions to reduce code size. Signed-off-by: NChristoph Lameter <clameter@sgi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Christoph Lameter 提交于
A kernel convention for many allocators is that if __GFP_ZERO is passed to an allocator then the allocated memory should be zeroed. This is currently not supported by the slab allocators. The inconsistency makes it difficult to implement in derived allocators such as in the uncached allocator and the pool allocators. In addition the support zeroed allocations in the slab allocators does not have a consistent API. There are no zeroing allocator functions for NUMA node placement (kmalloc_node, kmem_cache_alloc_node). The zeroing allocations are only provided for default allocs (kzalloc, kmem_cache_zalloc_node). __GFP_ZERO will make zeroing universally available and does not require any addititional functions. So add the necessary logic to all slab allocators to support __GFP_ZERO. The code is added to the hot path. The gfp flags are on the stack and so the cacheline is readily available for checking if we want a zeroed object. Zeroing while allocating is now a frequent operation and we seem to be gradually approaching a 1-1 parity between zeroing and not zeroing allocs. The current tree has 3476 uses of kmalloc vs 2731 uses of kzalloc. Signed-off-by: NChristoph Lameter <clameter@sgi.com> Acked-by: NPekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Christoph Lameter 提交于
Define ZERO_OR_NULL_PTR macro to be able to remove the checks from the allocators. Move ZERO_SIZE_PTR related stuff into slab.h. Make ZERO_SIZE_PTR work for all slab allocators and get rid of the WARN_ON_ONCE(size == 0) that is still remaining in SLAB. Make slub return NULL like the other allocators if a too large memory segment is requested via __kmalloc. Signed-off-by: NChristoph Lameter <clameter@sgi.com> Acked-by: NPekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Christoph Lameter 提交于
The size of a kmalloc object is readily available via ksize(). ksize is provided by all allocators and thus we can implement krealloc in a generic way. Implement krealloc in mm/util.c and drop slab specific implementations of krealloc. Signed-off-by: NChristoph Lameter <clameter@sgi.com> Acked-by: NPekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Christoph Lameter 提交于
The function we are calling to initialize object debug state during early NUMA bootstrap sets up an inactive object giving it the wrong redzone signature. The bootstrap nodes are active objects and should have active redzone signatures. Currently slab validation complains and reverts the object to active state. Signed-off-by: NChristoph Lameter <clameter@sgi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Christoph Lameter 提交于
Currently SLUB has no provision to deal with too high page orders that may be specified on the kernel boot line. If an order higher than 6 (on a 4k platform) is generated then we will BUG() because slabs get more than 65535 objects. Add some logic that decreases order for slabs that have too many objects. This allow booting with slab sizes up to MAX_ORDER. For example slub_min_order=10 will boot with a default slab size of 4M and reduce slab sizes for small object sizes to lower orders if the number of objects becomes too big. Large slab sizes like that allow a concentration of objects of the same slab cache under as few as possible TLB entries and thus potentially reduces TLB pressure. Signed-off-by: NChristoph Lameter <clameter@sgi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Christoph Lameter 提交于
We currently have to do an GFP_ATOMIC allocation because the list_lock is already taken when we first allocate memory for tracking allocation information. It would be better if we could avoid atomic allocations. Allocate a size of the tracking table that is usually sufficient (one page) before we take the list lock. We will then only do the atomic allocation if we need to resize the table to become larger than a page (mostly only needed under large NUMA because of the tracking of cpus and nodes otherwise the table stays small). Signed-off-by: NChristoph Lameter <clameter@sgi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Christoph Lameter 提交于
Use list_for_each_entry() instead of list_for_each(). Get rid of for_all_slabs(). It had only one user. So fold it into the callback. This also gets rid of cpu_slab_flush. Signed-off-by: NChristoph Lameter <clameter@sgi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Christoph Lameter 提交于
Changes the error reporting format to loosely follow lockdep. If data corruption is detected then we generate the following lines: ============================================ BUG <slab-cache>: <problem> -------------------------------------------- INFO: <more information> [possibly multiple times] <object dump> FIX <slab-cache>: <remedial action> This also adds some more intelligence to the data corruption detection. Its now capable of figuring out the start and end. Add a comment on how to configure SLUB so that a production system may continue to operate even though occasional slab corruption occur through a misbehaving kernel component. See "Emergency operations" in Documentation/vm/slub.txt. [akpm@linux-foundation.org: build fix] Signed-off-by: NChristoph Lameter <clameter@sgi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 17 7月, 2007 1 次提交
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由 Christoph Lameter 提交于
Add a new configuration variable CONFIG_SLUB_DEBUG_ON If set then the kernel will be booted by default with slab debugging switched on. Similar to CONFIG_SLAB_DEBUG. By default slab debugging is available but must be enabled by specifying "slub_debug" as a kernel parameter. Also add support to switch off slab debugging for a kernel that was built with CONFIG_SLUB_DEBUG_ON. This works by specifying slub_debug=- as a kernel parameter. Dave Jones wanted this feature. http://marc.info/?l=linux-kernel&m=118072189913045&w=2 [akpm@linux-foundation.org: clean up switch statement] Signed-off-by: NChristoph Lameter <clameter@sgi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 07 7月, 2007 1 次提交
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由 Christoph Lameter 提交于
kmem_cache_open is static. EXPORT_SYMBOL was leftover from some earlier time period where kmem_cache_open was usable outside of slub. (Fixes powerpc build error) Signed-off-by: NChrsitoph Lameter <clameter@sgi.com> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 04 7月, 2007 1 次提交
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由 Christoph Lameter 提交于
If we move the local_irq_enable() to the end of the function then add_partial() in early_kmem_cache_node_alloc() will be called with interrupts disabled like during regular operations. This makes lockdep happy. Signed-off-by: NChristoph Lameter <clameter@sgi.com> Tested-by: NAndre Noll <maan@systemlinux.org> Acked-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 24 6月, 2007 1 次提交
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由 Christoph Lameter 提交于
If slabs are allocated or freed from a large set of call sites (typical for the kmalloc area) then we may create more output than fits into a single PAGE and sysfs only gives us one page. The output should be truncated. This patch fixes the checks to do the truncation properly. Signed-off-by: NChristoph Lameter <clameter@sgi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 17 6月, 2007 2 次提交
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由 Christoph Lameter 提交于
If ARCH_KMALLOC_MINALIGN is set to a value greater than 8 (SLUBs smallest kmalloc cache) then SLUB may generate duplicate slabs in sysfs (yes again) because the object size is padded to reach ARCH_KMALLOC_MINALIGN. Thus the size of the small slabs is all the same. No arch sets ARCH_KMALLOC_MINALIGN larger than 8 though except mips which for some reason wants a 128 byte alignment. This patch increases the size of the smallest cache if ARCH_KMALLOC_MINALIGN is greater than 8. In that case more and more of the smallest caches are disabled. If we do that then the count of the active general caches that is displayed on boot is not correct anymore since we may skip elements of the kmalloc array. So count them separately. This approach was tested by Havard yesterday. Signed-off-by: NChristoph Lameter <clameter@sgi.com> Cc: Haavard Skinnemoen <hskinnemoen@atmel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Christoph Lameter 提交于
The data structure to manage the information gathered about functions allocating and freeing objects is allocated when the list_lock has already been taken. We need to allocate with GFP_ATOMIC instead of GFP_KERNEL. Signed-off-by: NChristoph Lameter <clameter@sgi.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Andy Whitcroft <apw@shadowen.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 09 6月, 2007 1 次提交
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由 Christoph Lameter 提交于
Instead of returning the smallest available object return ZERO_SIZE_PTR. A ZERO_SIZE_PTR can be legitimately used as an object pointer as long as it is not deferenced. The dereference of ZERO_SIZE_PTR causes a distinctive fault. kfree can handle a ZERO_SIZE_PTR in the same way as NULL. This enables functions to use zero sized object. e.g. n = number of objects. objects = kmalloc(n * sizeof(object)); for (i = 0; i < n; i++) objects[i].x = y; kfree(objects); Signed-off-by: NChristoph Lameter <clameter@sgi.com> Acked-by: NPekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 01 6月, 2007 1 次提交
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由 Christoph Lameter 提交于
Hotplug callbacks are performed with interrupts enabled. Slub requires interrupts to be disabled for flushing caches. Signed-off-by: NChristoph Lameter <clameter@sgi.com> Cc: Michal Piotrowski <michal.k.k.piotrowski@gmail.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 31 5月, 2007 1 次提交
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由 Christoph Lameter 提交于
We need this patch in ASAP. Patch fixes the mysterious hang that remained on some particular configurations with lockdep on after the first fix that moved the #idef CONFIG_SLUB_DEBUG to the right location. See http://marc.info/?t=117963072300001&r=1&w=2 The kmem_cache_node cache is very special because it is needed for NUMA bootstrap. Under certain conditions (like for example if lockdep is enabled and significantly increases the size of spinlock_t) the structure may become exactly the size as one of the larger caches in the kmalloc array. That early during bootstrap we cannot perform merging properly. The unique id for the kmem_cache_node cache will match one of the kmalloc array. Sysfs will complain about a duplicate directory entry. All of this occurs while the console is not yet fully operational. Thus boot may appear to be silently failing. The kmem_cache_node cache is very special. During early boostrap the main allocation function is not operational yet and so we have to run our own small special alloc function during early boot. It is also special in that it is never freed. We really do not want any merging on that cache. Set the refcount -1 and forbid merging of slabs that have a negative refcount. Signed-off-by: NChristoph Lameter <clameter@sgi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 24 5月, 2007 2 次提交
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由 Christoph Lameter 提交于
The check for super sized slabs where we can no longer move the free pointer behind the object for debugging purposes etc is accessing a field that is not setup yet. We must use objsize here since the size of the slab has not been determined yet. The effect of this is that a global slab shrink via "slabinfo -s" will show errors about offsets being wrong if booted with slub_debug. Potentially there are other troubles with huge slabs under slub_debug because the calculated free pointer offset is truncated. Signed-off-by: NChristoph Lameter <clameter@sgi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Christoph Lameter 提交于
The object size calculation is wrong if !CONFIG_SLUB_DEBUG because the #ifdef CONFIG_SLUB_DEBUG is now switching off the size adjustments for DESTROY_BY_RCU and ctor. Signed-off-by: NChristoph Lameter <clameter@sgi.com> Acked-by: NHugh Dickins <hugh@veritas.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 17 5月, 2007 6 次提交
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由 Christoph Lameter 提交于
Consolidate functionality into the #ifdef section. Extract tracing into one subroutine. Move object debug processing into the #ifdef section so that the code in __slab_alloc and __slab_free becomes minimal. Reduce number of functions we need to provide stubs for in the !SLUB_DEBUG case. Signed-off-by: NChristoph Lameter <clameter@sgi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Christoph Lameter 提交于
SLAB_CTOR_CONSTRUCTOR is always specified. No point in checking it. Signed-off-by: NChristoph Lameter <clameter@sgi.com> Cc: David Howells <dhowells@redhat.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Steven French <sfrench@us.ibm.com> Cc: Michael Halcrow <mhalcrow@us.ibm.com> Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Cc: Miklos Szeredi <miklos@szeredi.hu> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Dave Kleikamp <shaggy@austin.ibm.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: "J. Bruce Fields" <bfields@fieldses.org> Cc: Anton Altaparmakov <aia21@cantab.net> Cc: Mark Fasheh <mark.fasheh@oracle.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Jan Kara <jack@ucw.cz> Cc: David Chinner <dgc@sgi.com> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Christoph Lameter 提交于
The atomicity when handling flags in SLUB is not necessary since both flags used by SLUB are not updated in a racy way. Flag updates are either done during slab creation or destruction or under slab_lock. Some of these flags do not have the non atomic variants that we need. So define our own. Signed-off-by: NChristoph Lameter <clameter@sgi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Christoph Lameter 提交于
Use inline functions to access the per cpu bit. Intoduce the notion of "freezing" a slab to make things more understandable. Signed-off-by: NChristoph Lameter <clameter@sgi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Christoph Lameter 提交于
There is no user of destructors left. There is no reason why we should keep checking for destructors calls in the slab allocators. The RFC for this patch was discussed at http://marc.info/?l=linux-kernel&m=117882364330705&w=2 Destructors were mainly used for list management which required them to take a spinlock. Taking a spinlock in a destructor is a bit risky since the slab allocators may run the destructors anytime they decide a slab is no longer needed. Patch drops destructor support. Any attempt to use a destructor will BUG(). Acked-by: NPekka Enberg <penberg@cs.helsinki.fi> Acked-by: NPaul Mundt <lethal@linux-sh.org> Signed-off-by: NChristoph Lameter <clameter@sgi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Hugh Dickins 提交于
kmem_cache_create() was swapping ctor and dtor in calling find_mergeable(): though it caused no bug, and probably never would, even if destructors are retained; but fix it so as not to generate anxiety ;) Signed-off-by: NHugh Dickins <hugh@veritas.com> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 11 5月, 2007 2 次提交
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由 Christoph Lameter 提交于
This was in SLUB in order to head off trouble while the nr_cpu_ids functionality was not merged. Its merged now so no need to still have this. Signed-off-by: NChristoph Lameter <clameter@sgi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Christoph Lameter 提交于
Avoid atomic overhead in slab_alloc and slab_free SLUB needs to use the slab_lock for the per cpu slabs to synchronize with potential kfree operations. This patch avoids that need by moving all free objects onto a lockless_freelist. The regular freelist continues to exist and will be used to free objects. So while we consume the lockless_freelist the regular freelist may build up objects. If we are out of objects on the lockless_freelist then we may check the regular freelist. If it has objects then we move those over to the lockless_freelist and do this again. There is a significant savings in terms of atomic operations that have to be performed. We can even free directly to the lockless_freelist if we know that we are running on the same processor. So this speeds up short lived objects. They may be allocated and freed without taking the slab_lock. This is particular good for netperf. In order to maximize the effect of the new faster hotpath we extract the hottest performance pieces into inlined functions. These are then inlined into kmem_cache_alloc and kmem_cache_free. So hotpath allocation and freeing no longer requires a subroutine call within SLUB. [I am not sure that it is worth doing this because it changes the easy to read structure of slub just to reduce atomic ops. However, there is someone out there with a benchmark on 4 way and 8 way processor systems that seems to show a 5% regression vs. Slab. Seems that the regression is due to increased atomic operations use vs. SLAB in SLUB). I wonder if this is applicable or discernable at all in a real workload?] Signed-off-by: NChristoph Lameter <clameter@sgi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 10 5月, 2007 3 次提交
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由 Christoph Lameter 提交于
Currently the slab allocators contain callbacks into the page allocator to perform the draining of pagesets on remote nodes. This requires SLUB to have a whole subsystem in order to be compatible with SLAB. Moving node draining out of the slab allocators avoids a section of code in SLUB. Move the node draining so that is is done when the vm statistics are updated. At that point we are already touching all the cachelines with the pagesets of a processor. Add a expire counter there. If we have to update per zone or global vm statistics then assume that the pageset will require subsequent draining. The expire counter will be decremented on each vm stats update pass until it reaches zero. Then we will drain one batch from the pageset. The draining will cause vm counter updates which will then cause another expiration until the pcp is empty. So we will drain a batch every 3 seconds. Note that remote node draining is a somewhat esoteric feature that is required on large NUMA systems because otherwise significant portions of system memory can become trapped in pcp queues. The number of pcp is determined by the number of processors and nodes in a system. A system with 4 processors and 2 nodes has 8 pcps which is okay. But a system with 1024 processors and 512 nodes has 512k pcps with a high potential for large amount of memory being caught in them. Signed-off-by: NChristoph Lameter <clameter@sgi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Christoph Lameter 提交于
vmstat is currently using the cache reaper to periodically bring the statistics up to date. The cache reaper does only exists in SLUB as a way to provide compatibility with SLAB. This patch removes the vmstat calls from the slab allocators and provides its own handling. The advantage is also that we can use a different frequency for the updates. Refreshing vm stats is a pretty fast job so we can run this every second and stagger this by only one tick. This will lead to some overlap in large systems. F.e a system running at 250 HZ with 1024 processors will have 4 vm updates occurring at once. However, the vm stats update only accesses per node information. It is only necessary to stagger the vm statistics updates per processor in each node. Vm counter updates occurring on distant nodes will not cause cacheline contention. We could implement an alternate approach that runs the first processor on each node at the second and then each of the other processor on a node on a subsequent tick. That may be useful to keep a large amount of the second free of timer activity. Maybe the timer folks will have some feedback on this one? [jirislaby@gmail.com: add missing break] Cc: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: NChristoph Lameter <clameter@sgi.com> Signed-off-by: NJiri Slaby <jirislaby@gmail.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Rafael J. Wysocki 提交于
Since nonboot CPUs are now disabled after tasks and devices have been frozen and the CPU hotplug infrastructure is used for this purpose, we need special CPU hotplug notifications that will help the CPU-hotplug-aware subsystems distinguish normal CPU hotplug events from CPU hotplug events related to a system-wide suspend or resume operation in progress. This patch introduces such notifications and causes them to be used during suspend and resume transitions. It also changes all of the CPU-hotplug-aware subsystems to take these notifications into consideration (for now they are handled in the same way as the corresponding "normal" ones). [oleg@tv-sign.ru: cleanups] Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl> Cc: Gautham R Shenoy <ego@in.ibm.com> Cc: Pavel Machek <pavel@ucw.cz> Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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