- 17 Jul, 2007 40 commits
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Rafael J. Wysocki authored
Currently, the freezer treats all tasks as freezable, except for the kernel threads that explicitly set the PF_NOFREEZE flag for themselves. This approach is problematic, since it requires every kernel thread to either set PF_NOFREEZE explicitly, or call try_to_freeze(), even if it doesn't care for the freezing of tasks at all. It seems better to only require the kernel threads that want to or need to be frozen to use some freezer-related code and to remove any freezer-related code from the other (nonfreezable) kernel threads, which is done in this patch. The patch causes all kernel threads to be nonfreezable by default (ie. to have PF_NOFREEZE set by default) and introduces the set_freezable() function that should be called by the freezable kernel threads in order to unset PF_NOFREEZE. It also makes all of the currently freezable kernel threads call set_freezable(), so it shouldn't cause any (intentional) change of behaviour to appear. Additionally, it updates documentation to describe the freezing of tasks more accurately. [akpm@linux-foundation.org: build fixes] Signed-off-by:
Rafael J. Wysocki <rjw@sisk.pl> Acked-by:
Nigel Cunningham <nigel@nigel.suspend2.net> Cc: Pavel Machek <pavel@ucw.cz> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Nick Piggin authored
It is a bug to set a page dirty if it is not uptodate unless it has buffers. If the page has buffers, then the page may be dirty (some buffers dirty) but not uptodate (some buffers not uptodate). The exception to this rule is if the set_page_dirty caller is racing with truncate or invalidate. A buffer can not be set dirty if it is not uptodate. If either of these situations occurs, it indicates there could be some data loss problem. Some of these warnings could be a harmless one where the page or buffer is set uptodate immediately after it is dirtied, however we should fix those up, and enforce this ordering. Bring the order of operations for truncate into line with those of invalidate. This will prevent a page from being able to go !uptodate while we're holding the tree_lock, which is probably a good thing anyway. Signed-off-by:
Nick Piggin <npiggin@suse.de> Signed-off-by:
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Robert P. J. Day authored
Signed-off-by:
Robert P. J. Day <rpjday@mindspring.com> Signed-off-by:
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Christoph Lameter authored
Detect slab objects being passed to the page oriented functions of the VM. It is not sufficient to simply return NULL because the functions calling page_mapping may depend on other items of the page_struct also to be setup properly. Moreover slab object may not be properly aligned. The page oriented functions of the VM expect to operate on page aligned, page sized objects. Operations on object straddling page boundaries may only affect the objects partially which may lead to surprising results. It is better to detect eventually remaining uses and eliminate them. Signed-off-by:
Christoph Lameter <clameter@sgi.com> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by:
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Christoph Lameter authored
There are some reports that 2.6.22 has SLUB as the default. Not true! This will make SLUB the default for 2.6.23. Signed-off-by:
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Christoph Lameter authored
We currently cannot disable CONFIG_SLUB_DEBUG for CONFIG_NUMA. Now that embedded systems start to use NUMA we may need this. Put an #ifdef around places where NUMA only code uses fields only valid for CONFIG_SLUB_DEBUG. Signed-off-by:
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Christoph Lameter authored
Sysfs can do a gazillion things when called. Make sure that we do not call any sysfs functions while holding the slub_lock. Just protect the essentials: 1. The list of all slab caches 2. The kmalloc_dma array 3. The ref counters of the slabs. Signed-off-by:
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Christoph Lameter authored
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:
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Christoph Lameter authored
kmalloc_node() and kmem_cache_alloc_node() were not available in a zeroing variant in the past. But with __GFP_ZERO it is possible now to do zeroing while allocating. Use __GFP_ZERO to remove the explicit clearing of memory via memset whereever we can. Signed-off-by:
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Christoph Lameter authored
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:
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Christoph Lameter authored
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:
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Christoph Lameter authored
Do proper spacing and we only need to do this in steps of 8. Signed-off-by:
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Adrian Bunk authored
Signed-off-by:
Adrian Bunk <bunk@stusta.de> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by:
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Christoph Lameter authored
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:
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Christoph Lameter authored
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:
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Christoph Lameter authored
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:
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Christoph Lameter authored
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:
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Christoph Lameter authored
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:
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Christoph Lameter authored
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:
Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by:
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Christoph Lameter authored
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:
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Christoph Lameter authored
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:
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Christoph Lameter authored
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:
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Christoph Lameter authored
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:
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Christoph Lameter authored
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:
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Christoph Lameter authored
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:
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Christoph Lameter authored
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:
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Rusty Russell authored
I can never remember what the function to register to receive VM pressure is called. I have to trace down from __alloc_pages() to find it. It's called "set_shrinker()", and it needs Your Help. 1) Don't hide struct shrinker. It contains no magic. 2) Don't allocate "struct shrinker". It's not helpful. 3) Call them "register_shrinker" and "unregister_shrinker". 4) Call the function "shrink" not "shrinker". 5) Reduce the 17 lines of waffly comments to 13, but document it properly. Signed-off-by:
Rusty Russell <rusty@rustcorp.com.au> Cc: David Chinner <dgc@sgi.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by:
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Andy Whitcroft authored
When we are out of memory of a suitable size we enter reclaim. The current reclaim algorithm targets pages in LRU order, which is great for fairness at order-0 but highly unsuitable if you desire pages at higher orders. To get pages of higher order we must shoot down a very high proportion of memory; >95% in a lot of cases. This patch set adds a lumpy reclaim algorithm to the allocator. It targets groups of pages at the specified order anchored at the end of the active and inactive lists. This encourages groups of pages at the requested orders to move from active to inactive, and active to free lists. This behaviour is only triggered out of direct reclaim when higher order pages have been requested. This patch set is particularly effective when utilised with an anti-fragmentation scheme which groups pages of similar reclaimability together. This patch set is based on Peter Zijlstra's lumpy reclaim V2 patch which forms the foundation. Credit to Mel Gorman for sanitity checking. Mel said: The patches have an application with hugepage pool resizing. When lumpy-reclaim is used used with ZONE_MOVABLE, the hugepages pool can be resized with greater reliability. Testing on a desktop machine with 2GB of RAM showed that growing the hugepage pool with ZONE_MOVABLE on it's own was very slow as the success rate was quite low. Without lumpy-reclaim, each attempt to grow the pool by 100 pages would yield 1 or 2 hugepages. With lumpy-reclaim, getting 40 to 70 hugepages on each attempt was typical. [akpm@osdl.org: ia64 pfn_to_nid fixes and loop cleanup] [bunk@stusta.de: static declarations for internal functions] [a.p.zijlstra@chello.nl: initial lumpy V2 implementation] Signed-off-by:
Andy Whitcroft <apw@shadowen.org> Acked-by:
Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by:
Mel Gorman <mel@csn.ul.ie> Acked-by:
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Mel Gorman authored
This patch adds a new parameter for sizing ZONE_MOVABLE called movablecore=. While kernelcore= is used to specify the minimum amount of memory that must be available for all allocation types, movablecore= is used to specify the minimum amount of memory that is used for migratable allocations. The amount of memory used for migratable allocations determines how large the huge page pool could be dynamically resized to at runtime for example. How movablecore is actually handled is that the total number of pages in the system is calculated and a value is set for kernelcore that is kernelcore == totalpages - movablecore Both kernelcore= and movablecore= can be safely specified at the same time. Signed-off-by:
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Mel Gorman authored
This patch adds the kernelcore= parameter for x86. Once all patches are applied, a new command-line parameter exist and a new sysctl. This patch adds the necessary documentation. From: Yasunori Goto <y-goto@jp.fujitsu.com> When "kernelcore" boot option is specified, kernel can't boot up on ia64 because of an infinite loop. In addition, the parsing code can be handled in an architecture-independent manner. This patch uses common code to handle the kernelcore= parameter. It is only available to architectures that support arch-independent zone-sizing (i.e. define CONFIG_ARCH_POPULATES_NODE_MAP). Other architectures will ignore the boot parameter. [bunk@stusta.de: make cmdline_parse_kernelcore() static] Signed-off-by:
Yasunori Goto <y-goto@jp.fujitsu.com> Acked-by:
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Mel Gorman authored
Huge pages are not movable so are not allocated from ZONE_MOVABLE. However, as ZONE_MOVABLE will always have pages that can be migrated or reclaimed, it can be used to satisfy hugepage allocations even when the system has been running a long time. This allows an administrator to resize the hugepage pool at runtime depending on the size of ZONE_MOVABLE. This patch adds a new sysctl called hugepages_treat_as_movable. When a non-zero value is written to it, future allocations for the huge page pool will use ZONE_MOVABLE. Despite huge pages being non-movable, we do not introduce additional external fragmentation of note as huge pages are always the largest contiguous block we care about. [akpm@linux-foundation.org: various fixes] Signed-off-by:
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Mel Gorman authored
The following 8 patches against 2.6.20-mm2 create a zone called ZONE_MOVABLE that is only usable by allocations that specify both __GFP_HIGHMEM and __GFP_MOVABLE. This has the effect of keeping all non-movable pages within a single memory partition while allowing movable allocations to be satisfied from either partition. The patches may be applied with the list-based anti-fragmentation patches that groups pages together based on mobility. The size of the zone is determined by a kernelcore= parameter specified at boot-time. This specifies how much memory is usable by non-movable allocations and the remainder is used for ZONE_MOVABLE. Any range of pages within ZONE_MOVABLE can be released by migrating the pages or by reclaiming. When selecting a zone to take pages from for ZONE_MOVABLE, there are two things to consider. First, only memory from the highest populated zone is used for ZONE_MOVABLE. On the x86, this is probably going to be ZONE_HIGHMEM but it would be ZONE_DMA on ppc64 or possibly ZONE_DMA32 on x86_64. Second, the amount of memory usable by the kernel will be spread evenly throughout NUMA nodes where possible. If the nodes are not of equal size, the amount of memory usable by the kernel on some nodes may be greater than others. By default, the zone is not as useful for hugetlb allocations because they are pinned and non-migratable (currently at least). A sysctl is provided that allows huge pages to be allocated from that zone. This means that the huge page pool can be resized to the size of ZONE_MOVABLE during the lifetime of the system assuming that pages are not mlocked. Despite huge pages being non-movable, we do not introduce additional external fragmentation of note as huge pages are always the largest contiguous block we care about. Credit goes to Andy Whitcroft for catching a large variety of problems during review of the patches. This patch creates an additional zone, ZONE_MOVABLE. This zone is only usable by allocations which specify both __GFP_HIGHMEM and __GFP_MOVABLE. Hot-added memory continues to be placed in their existing destination as there is no mechanism to redirect them to a specific zone. [y-goto@jp.fujitsu.com: Fix section mismatch of memory hotplug related code] [akpm@linux-foundation.org: various fixes] Signed-off-by:
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Mel Gorman authored
It is often known at allocation time whether a page may be migrated or not. This patch adds a flag called __GFP_MOVABLE and a new mask called GFP_HIGH_MOVABLE. Allocations using the __GFP_MOVABLE can be either migrated using the page migration mechanism or reclaimed by syncing with backing storage and discarding. An API function very similar to alloc_zeroed_user_highpage() is added for __GFP_MOVABLE allocations called alloc_zeroed_user_highpage_movable(). The flags used by alloc_zeroed_user_highpage() are not changed because it would change the semantics of an existing API. After this patch is applied there are no in-kernel users of alloc_zeroed_user_highpage() so it probably should be marked deprecated if this patch is merged. Note that this patch includes a minor cleanup to the use of __GFP_ZERO in shmem.c to keep all flag modifications to inode->mapping in the shmem_dir_alloc() helper function. This clean-up suggestion is courtesy of Hugh Dickens. Additional credit goes to Christoph Lameter and Linus Torvalds for shaping the concept. Credit to Hugh Dickens for catching issues with shmem swap vector and ramfs allocations. [akpm@linux-foundation.org: build fix] [hugh@veritas.com: __GFP_ZERO cleanup] Signed-off-by:
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NeilBrown authored
do_generic_mapping_read currently samples the i_size at the start and doesn't do so again unless it needs to call ->readpage to load a page. After ->readpage it has to re-sample i_size as a truncate may have caused that page to be filled with zeros, and the read() call should not see these. However there are other activities that might cause ->readpage to be called on a page between the time that do_generic_mapping_read samples i_size and when it finds that it has an uptodate page. These include at least read-ahead and possibly another thread performing a read. So do_generic_mapping_read must sample i_size *after* it has an uptodate page. Thus the current sampling at the start and after a read can be replaced with a sampling before the copy-out. The same change applied to __generic_file_splice_read. Note that this fixes any race with truncate_complete_page, but does not fix a possible race with truncate_partial_page. If a partial truncate happens after do_generic_mapping_read samples i_size and before the copy_out, the nuls that truncate_partial_page place in the page could be copied out incorrectly. I think the best fix for that is to *not* zero out parts of the page in truncate_partial_page, but rather to zero out the tail of a page when increasing i_size. Signed-off-by:
Neil Brown <neilb@suse.de> Cc: Jens Axboe <jens.axboe@oracle.com> Acked-by:
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Martin Schwidefsky authored
Nobody is using ptep_test_and_clear_dirty and ptep_clear_flush_dirty. Remove the functions from all architectures. Signed-off-by:
Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by:
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Martin Schwidefsky authored
The last user of ptep_establish in mm/ is long gone. Remove the architecture primitive as well. Signed-off-by:
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Yoann Padioleau authored
Signed-off-by:
Yoann Padioleau <padator@wanadoo.fr> Cc: Jean Delvare <khali@linux-fr.org> Signed-off-by:
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ssh://master.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6Linus Torvalds authored
* 'drm-patches' of ssh://master.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6: drm: add idr_init to drm_stub.c drm: fix problem with SiS typedef with sisfb enabled.
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Dave Airlie authored
Brown paper bag for me this patch chunk didn't make it in the first application Signed-off-by:Dave Airlie <airlied@linux.ie>
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Dave Airlie authored
Reported by: Avuton Olrich <avuton@gmail.com> Signed-off-by:
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