summaryrefslogtreecommitdiffstats
Commit message (Collapse)AuthorAgeFilesLines
...
* Quicklists for page table pagesChristoph Lameter2007-05-074-0/+189
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On x86_64 this cuts allocation overhead for page table pages down to a fraction (kernel compile / editing load. TSC based measurement of times spend in each function): no quicklist pte_alloc 1569048 4.3s(401ns/2.7us/179.7us) pmd_alloc 780988 2.1s(337ns/2.7us/86.1us) pud_alloc 780072 2.2s(424ns/2.8us/300.6us) pgd_alloc 260022 1s(920ns/4us/263.1us) quicklist: pte_alloc 452436 573.4ms(8ns/1.3us/121.1us) pmd_alloc 196204 174.5ms(7ns/889ns/46.1us) pud_alloc 195688 172.4ms(7ns/881ns/151.3us) pgd_alloc 65228 9.8ms(8ns/150ns/6.1us) pgd allocations are the most complex and there we see the most dramatic improvement (may be we can cut down the amount of pgds cached somewhat?). But even the pte allocations still see a doubling of performance. 1. Proven code from the IA64 arch. The method used here has been fine tuned for years and is NUMA aware. It is based on the knowledge that accesses to page table pages are sparse in nature. Taking a page off the freelists instead of allocating a zeroed pages allows a reduction of number of cachelines touched in addition to getting rid of the slab overhead. So performance improves. This is particularly useful if pgds contain standard mappings. We can save on the teardown and setup of such a page if we have some on the quicklists. This includes avoiding lists operations that are otherwise necessary on alloc and free to track pgds. 2. Light weight alternative to use slab to manage page size pages Slab overhead is significant and even page allocator use is pretty heavy weight. The use of a per cpu quicklist means that we touch only two cachelines for an allocation. There is no need to access the page_struct (unless arch code needs to fiddle around with it). So the fast past just means bringing in one cacheline at the beginning of the page. That same cacheline may then be used to store the page table entry. Or a second cacheline may be used if the page table entry is not in the first cacheline of the page. The current code will zero the page which means touching 32 cachelines (assuming 128 byte). We get down from 32 to 2 cachelines in the fast path. 3. x86_64 gets lightweight page table page management. This will allow x86_64 arch code to faster repopulate pgds and other page table entries. The list operations for pgds are reduced in the same way as for i386 to the point where a pgd is allocated from the page allocator and when it is freed back to the page allocator. A pgd can pass through the quicklists without having to be reinitialized. 64 Consolidation of code from multiple arches So far arches have their own implementation of quicklist management. This patch moves that feature into the core allowing an easier maintenance and consistent management of quicklists. Page table pages have the characteristics that they are typically zero or in a known state when they are freed. This is usually the exactly same state as needed after allocation. So it makes sense to build a list of freed page table pages and then consume the pages already in use first. Those pages have already been initialized correctly (thus no need to zero them) and are likely already cached in such a way that the MMU can use them most effectively. Page table pages are used in a sparse way so zeroing them on allocation is not too useful. Such an implementation already exits for ia64. Howver, that implementation did not support constructors and destructors as needed by i386 / x86_64. It also only supported a single quicklist. The implementation here has constructor and destructor support as well as the ability for an arch to specify how many quicklists are needed. Quicklists are defined by an arch defining CONFIG_QUICKLIST. If more than one quicklist is necessary then we can define NR_QUICK for additional lists. F.e. i386 needs two and thus has config NR_QUICK int default 2 If an arch has requested quicklist support then pages can be allocated from the quicklist (or from the page allocator if the quicklist is empty) via: quicklist_alloc(<quicklist-nr>, <gfpflags>, <constructor>) Page table pages can be freed using: quicklist_free(<quicklist-nr>, <destructor>, <page>) Pages must have a definite state after allocation and before they are freed. If no constructor is specified then pages will be zeroed on allocation and must be zeroed before they are freed. If a constructor is used then the constructor will establish a definite page state. F.e. the i386 and x86_64 pgd constructors establish certain mappings. Constructors and destructors can also be used to track the pages. i386 and x86_64 use a list of pgds in order to be able to dynamically update standard mappings. Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Andi Kleen <ak@suse.de> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: William Lee Irwin III <wli@holomorphy.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* slub: add slabinfo toolChristoph Lameter2007-05-071-0/+943
| | | | | | | | Add the tool which gets reports about slabs to the VM documentation directory. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* slub: user documentationChristoph Lameter2007-05-071-0/+113
| | | | | | Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* slub: remove object activities out of checking functionsChristoph Lameter2007-05-071-61/+47
| | | | | | | | | | Make sure that the check function really only check things and do not perform activities. Extract the tracing and object seeding out of the two check functions and place them into slab_alloc and slab_free Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* SLUB: Free slabs and sort partial slab lists in kmem_cache_shrinkChristoph Lameter2007-05-071-13/+112
| | | | | | | | | | | | | | | | | | | | | | | | | | At kmem_cache_shrink check if we have any empty slabs on the partial if so then remove them. Also--as an anti-fragmentation measure--sort the partial slabs so that the most fully allocated ones come first and the least allocated last. The next allocations may fill up the nearly full slabs. Having the least allocated slabs last gives them the maximum chance that their remaining objects may be freed. Thus we can hopefully minimize the partial slabs. I think this is the best one can do in terms antifragmentation measures. Real defragmentation (meaning moving objects out of slabs with the least free objects to those that are almost full) can be implemted by reverse scanning through the list produced here but that would mean that we need to provide a callback at slab cache creation that allows the deletion or moving of an object. This will involve slab API changes, so defer for now. Cc: Mel Gorman <mel@skynet.ie> Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* slub: add ability to list alloc / free callers per slabChristoph Lameter2007-05-071-3/+181
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch enables listing the callers who allocated or freed objects in a cache. For example to list the allocators for kmalloc-128 do cat /sys/slab/kmalloc-128/alloc_calls 7 sn_io_slot_fixup+0x40/0x700 7 sn_io_slot_fixup+0x80/0x700 9 sn_bus_fixup+0xe0/0x380 6 param_sysfs_setup+0xf0/0x280 276 percpu_populate+0xf0/0x1a0 19 __register_chrdev_region+0x30/0x360 8 expand_files+0x2e0/0x6e0 1 sys_epoll_create+0x60/0x200 1 __mounts_open+0x140/0x2c0 65 kmem_alloc+0x110/0x280 3 alloc_disk_node+0xe0/0x200 33 as_get_io_context+0x90/0x280 74 kobject_kset_add_dir+0x40/0x140 12 pci_create_bus+0x2a0/0x5c0 1 acpi_ev_create_gpe_block+0x120/0x9e0 41 con_insert_unipair+0x100/0x1c0 1 uart_open+0x1c0/0xba0 1 dma_pool_create+0xe0/0x340 2 neigh_table_init_no_netlink+0x260/0x4c0 6 neigh_parms_alloc+0x30/0x200 1 netlink_kernel_create+0x130/0x320 5 fz_hash_alloc+0x50/0xe0 2 sn_common_hubdev_init+0xd0/0x6e0 28 kernel_param_sysfs_setup+0x30/0x180 72 process_zones+0x70/0x2e0 cat /sys/slab/kmalloc-128/free_calls 558 <not-available> 3 sn_io_slot_fixup+0x600/0x700 84 free_fdtable_rcu+0x120/0x260 2 seq_release+0x40/0x60 6 kmem_free+0x70/0xc0 24 free_as_io_context+0x20/0x200 1 acpi_get_object_info+0x3a0/0x3e0 1 acpi_add_single_object+0xcf0/0x1e40 2 con_release_unimap+0x80/0x140 1 free+0x20/0x40 SLAB_STORE_USER must be enabled for a slab cache by either booting with "slab_debug" or enabling user tracking specifically for the slab of interest. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* SLUB: Add MIN_PARTIALChristoph Lameter2007-05-071-19/+36
| | | | | | | | | | | | | | | | | | | | We leave a mininum of partial slabs on nodes when we search for partial slabs on other node. Define a constant for that value. Then modify slub to keep MIN_PARTIAL slabs around. This avoids bad situations where a function frees the last object in a slab (which results in the page being returned to the page allocator) only to then allocate one again (which requires getting a page back from the page allocator if the partial list was empty). Keeping a couple of slabs on the partial list reduces overhead. Empty slabs are added to the end of the partial list to insure that partially allocated slabs are consumed first (defragmentation). Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* slub: validation of slabs (metadata and guard zones)Christoph Lameter2007-05-071-3/+110
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This enables validation of slab. Validation means that all objects are checked to see if there are redzone violations, if padding has been overwritten or any pointers have been corrupted. Also checks the consistency of slab counters. Validation enables the detection of metadata corruption without the kernel having to execute code that actually uses (allocs/frees) and object. It allows one to make sure that the slab metainformation and the guard values around an object have not been compromised. A single slabcache can be checked by writing a 1 to the "validate" file. i.e. echo 1 >/sys/slab/kmalloc-128/validate or use the slabinfo tool to check all slabs slabinfo -v Error messages will show up in the syslog. Note that validation can only reach slabs that are on a list. This means that we are usually restricted to partial slabs and active slabs unless SLAB_STORE_USER is active which will build a full slab list and allows validation of slabs that are fully in use. Booting with "slub_debug" set will enable SLAB_STORE_USER and then full diagnostic are available. Note that we attempt to push cpu slabs back to the lists when we start the check. If the cpu slab is reactivated before we get to it (another processor grabs it before we get to it) then it cannot be checked. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* slub: enable tracking of full slabsChristoph Lameter2007-05-072-1/+41
| | | | | | | | | | If slab tracking is on then build a list of full slabs so that we can verify the integrity of all slabs and are also able to built list of alloc/free callers. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* slub: fix object trackingChristoph Lameter2007-05-071-37/+20
| | | | | | | | | | Object tracking did not work the right way for several call chains. Fix this up by adding a new parameter to slub_alloc and slub_free that specifies the caller address explicitly. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Add virt_to_head_page and consolidate code in slab and slubChristoph Lameter2007-05-073-11/+14
| | | | | | Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: optimize compound_head() by avoiding a shared page flagChristoph Lameter2007-05-073-26/+32
| | | | | | | | | | The patch adds PageTail(page) and PageHead(page) to check if a page is the head or the tail of a compound page. This is done by masking the two bits describing the state of a compound page and then comparing them. So one comparision and a branch instead of two bit checks and two branches. Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Make page->private usable in compound pagesChristoph Lameter2007-05-079-37/+72
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If we add a new flag so that we can distinguish between the first page and the tail pages then we can avoid to use page->private in the first page. page->private == page for the first page, so there is no real information in there. Freeing up page->private makes the use of compound pages more transparent. They become more usable like real pages. Right now we have to be careful f.e. if we are going beyond PAGE_SIZE allocations in the slab on i386 because we can then no longer use the private field. This is one of the issues that cause us not to support debugging for page size slabs in SLAB. Having page->private available for SLUB would allow more meta information in the page struct. I can probably avoid the 16 bit ints that I have in there right now. Also if page->private is available then a compound page may be equipped with buffer heads. This may free up the way for filesystems to support larger blocks than page size. We add PageTail as an alias of PageReclaim. Compound pages cannot currently be reclaimed. Because of the alias one needs to check PageCompound first. The RFC for the this approach was discussed at http://marc.info/?t=117574302800001&r=1&w=2 [nacc@us.ibm.com: fix hugetlbfs] Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* PowerPC: Disable SLUB for configurations in which slab page structs are modifiedChristoph Lameter2007-05-071-0/+13
| | | | | | | | | | | | | PowerPC uses the slab allocator to manage the lowest level of the page table. In high cpu configurations we also use the page struct to split the page table lock. Disallow the selection of SLUB for that case. Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Paul Mackerras <paulus@samba.org> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* SLUB: allocate smallest object size if the user asks for 0 bytesChristoph Lameter2007-05-072-3/+7
| | | | | | | | | | | | | | Makes SLUB behave like SLAB in this area to avoid issues.... Throw a stack dump to alert people. At some point the behavior should be switched back. NULL is no memory as far as I can tell and if the use asked for 0 bytes then he need to get no memory. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* SLUB: change default alignmentsChristoph Lameter2007-05-071-2/+2
| | | | | | | | | | | | | | | | | | | | | Structures may contain u64 items on 32 bit platforms that are only able to address 64 bit items on 64 bit boundaries. Change the mininum alignment of slabs to conform to those expectations. ARCH_KMALLOC_MINALIGN must be changed for good since a variety of structure are mixed in the general slabs. ARCH_SLAB_MINALIGN is changed because currently there is no consistent specification of object alignment. We may have that in the future when the KMEM_CACHE and related macros are used to generate slabs. These pass the alignment of the structure generated by the compiler to the slab. With KMEM_CACHE etc we could align structures that do not contain 64 bit values to 32 bit boundaries potentially saving some memory. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* SLUB coreChristoph Lameter2007-05-079-19/+3422
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is a new slab allocator which was motivated by the complexity of the existing code in mm/slab.c. It attempts to address a variety of concerns with the existing implementation. A. Management of object queues A particular concern was the complex management of the numerous object queues in SLAB. SLUB has no such queues. Instead we dedicate a slab for each allocating CPU and use objects from a slab directly instead of queueing them up. B. Storage overhead of object queues SLAB Object queues exist per node, per CPU. The alien cache queue even has a queue array that contain a queue for each processor on each node. For very large systems the number of queues and the number of objects that may be caught in those queues grows exponentially. On our systems with 1k nodes / processors we have several gigabytes just tied up for storing references to objects for those queues This does not include the objects that could be on those queues. One fears that the whole memory of the machine could one day be consumed by those queues. C. SLAB meta data overhead SLAB has overhead at the beginning of each slab. This means that data cannot be naturally aligned at the beginning of a slab block. SLUB keeps all meta data in the corresponding page_struct. Objects can be naturally aligned in the slab. F.e. a 128 byte object will be aligned at 128 byte boundaries and can fit tightly into a 4k page with no bytes left over. SLAB cannot do this. D. SLAB has a complex cache reaper SLUB does not need a cache reaper for UP systems. On SMP systems the per CPU slab may be pushed back into partial list but that operation is simple and does not require an iteration over a list of objects. SLAB expires per CPU, shared and alien object queues during cache reaping which may cause strange hold offs. E. SLAB has complex NUMA policy layer support SLUB pushes NUMA policy handling into the page allocator. This means that allocation is coarser (SLUB does interleave on a page level) but that situation was also present before 2.6.13. SLABs application of policies to individual slab objects allocated in SLAB is certainly a performance concern due to the frequent references to memory policies which may lead a sequence of objects to come from one node after another. SLUB will get a slab full of objects from one node and then will switch to the next. F. Reduction of the size of partial slab lists SLAB has per node partial lists. This means that over time a large number of partial slabs may accumulate on those lists. These can only be reused if allocator occur on specific nodes. SLUB has a global pool of partial slabs and will consume slabs from that pool to decrease fragmentation. G. Tunables SLAB has sophisticated tuning abilities for each slab cache. One can manipulate the queue sizes in detail. However, filling the queues still requires the uses of the spin lock to check out slabs. SLUB has a global parameter (min_slab_order) for tuning. Increasing the minimum slab order can decrease the locking overhead. The bigger the slab order the less motions of pages between per CPU and partial lists occur and the better SLUB will be scaling. G. Slab merging We often have slab caches with similar parameters. SLUB detects those on boot up and merges them into the corresponding general caches. This leads to more effective memory use. About 50% of all caches can be eliminated through slab merging. This will also decrease slab fragmentation because partial allocated slabs can be filled up again. Slab merging can be switched off by specifying slub_nomerge on boot up. Note that merging can expose heretofore unknown bugs in the kernel because corrupted objects may now be placed differently and corrupt differing neighboring objects. Enable sanity checks to find those. H. Diagnostics The current slab diagnostics are difficult to use and require a recompilation of the kernel. SLUB contains debugging code that is always available (but is kept out of the hot code paths). SLUB diagnostics can be enabled via the "slab_debug" option. Parameters can be specified to select a single or a group of slab caches for diagnostics. This means that the system is running with the usual performance and it is much more likely that race conditions can be reproduced. I. Resiliency If basic sanity checks are on then SLUB is capable of detecting common error conditions and recover as best as possible to allow the system to continue. J. Tracing Tracing can be enabled via the slab_debug=T,<slabcache> option during boot. SLUB will then protocol all actions on that slabcache and dump the object contents on free. K. On demand DMA cache creation. Generally DMA caches are not needed. If a kmalloc is used with __GFP_DMA then just create this single slabcache that is needed. For systems that have no ZONE_DMA requirement the support is completely eliminated. L. Performance increase Some benchmarks have shown speed improvements on kernbench in the range of 5-10%. The locking overhead of slub is based on the underlying base allocation size. If we can reliably allocate larger order pages then it is possible to increase slub performance much further. The anti-fragmentation patches may enable further performance increases. Tested on: i386 UP + SMP, x86_64 UP + SMP + NUMA emulation, IA64 NUMA + Simulator SLUB Boot options slub_nomerge Disable merging of slabs slub_min_order=x Require a minimum order for slab caches. This increases the managed chunk size and therefore reduces meta data and locking overhead. slub_min_objects=x Mininum objects per slab. Default is 8. slub_max_order=x Avoid generating slabs larger than order specified. slub_debug Enable all diagnostics for all caches slub_debug=<options> Enable selective options for all caches slub_debug=<o>,<cache> Enable selective options for a certain set of caches Available Debug options F Double Free checking, sanity and resiliency R Red zoning P Object / padding poisoning U Track last free / alloc T Trace all allocs / frees (only use for individual slabs). To use SLUB: Apply this patch and then select SLUB as the default slab allocator. [hugh@veritas.com: fix an oops-causing locking error] [akpm@linux-foundation.org: various stupid cleanups and small fixes] Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tty_register_driver: only allocate tty instances when definedAndy Whitcroft2007-05-071-3/+2
| | | | | | | | | | | | If device->num is zero we attempt to kmalloc() zero bytes. When SLUB is enabled this returns a null pointer and take that as an allocation failure and fail the device register. Check for no devices and avoid the allocation. [akpm: opportunistic kzalloc() conversion] Signed-off-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* i386: use page allocator to allocate thread_info structureChristoph Lameter2007-05-071-3/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | i386 uses kmalloc to allocate the threadinfo structure assuming that the allocations result in a page sized aligned allocation. That has worked so far because SLAB exempts page sized slabs from debugging and aligns them in special ways that goes beyond the restrictions imposed by KMALLOC_ARCH_MINALIGN valid for other slabs in the kmalloc array. SLUB also works fine without debugging since page sized allocations neatly align at page boundaries. However, if debugging is switched on then SLUB will extend the slab with debug information. The resulting slab is not longer of page size. It will only be aligned following the requirements imposed by KMALLOC_ARCH_MINALIGN. As a result the threadinfo structure may not be page aligned which makes i386 fail to boot with SLUB debug on. Replace the calls to kmalloc with calls into the page allocator. An alternate solution may be to create a custom slab cache where the alignment is set to PAGE_SIZE. That would allow slub debugging to be applied to the threadinfo structure. Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpusets: allow TIF_MEMDIE threads to allocate anywhereDavid Rientjes2007-05-071-2/+20
| | | | | | | | | | | | | | | | | | OOM killed tasks have access to memory reserves as specified by the TIF_MEMDIE flag in the hopes that it will quickly exit. If such a task has memory allocations constrained by cpusets, we may encounter a deadlock if a blocking task cannot exit because it cannot allocate the necessary memory. We allow tasks that have the TIF_MEMDIE flag to allocate memory anywhere, including outside its cpuset restriction, so that it can quickly die regardless of whether it is __GFP_HARDWALL. Cc: Andi Kleen <ak@suse.de> Cc: Paul Jackson <pj@sgi.com> Cc: Christoph Lameter <clameter@engr.sgi.com> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* slab: mark set_up_list3s() __initAndrew Morton2007-05-071-1/+1
| | | | | | | | | | | | | It is only ever used prior to free_initmem(). (It will cause a warning when we run the section checking, but that's a false-positive and it simply changes the source of an existing warning, which is also a false-positive) Cc: Christoph Lameter <clameter@engr.sgi.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Do not disable interrupts when reading min_free_kbytesMel Gorman2007-05-071-1/+2
| | | | | | | | | | | | | | | | | The sysctl handler for min_free_kbytes calls setup_per_zone_pages_min() on read or write. This function iterates through every zone and calls spin_lock_irqsave() on the zone LRU lock. When reading min_free_kbytes, this is a total waste of time that disables interrupts on the local processor. It might even be noticable machines with large numbers of zones if a process started constantly reading min_free_kbytes. This patch only calls setup_per_zone_pages_min() only on write. Tested on an x86 laptop and it did the right thing. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Christoph Lameter <clameter@engr.sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* slab: NUMA kmem_cache dietEric Dumazet2007-05-071-4/+20
| | | | | | | | | | | | | | | | | | | | | | | | Some NUMA machines have a big MAX_NUMNODES (possibly 1024), but fewer possible nodes. This patch dynamically sizes the 'struct kmem_cache' to allocate only needed space. I moved nodelists[] field at the end of struct kmem_cache, and use the following computation in kmem_cache_init() cache_cache.buffer_size = offsetof(struct kmem_cache, nodelists) + nr_node_ids * sizeof(struct kmem_list3 *); On my two nodes x86_64 machine, kmem_cache.obj_size is now 192 instead of 704 (This is because on x86_64, MAX_NUMNODES is 64) On bigger NUMA setups, this might reduce the gfporder of "cache_cache" Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Andy Whitcroft <apw@shadowen.org> Cc: Christoph Lameter <clameter@engr.sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* SLAB: don't allocate empty shared cachesEric Dumazet2007-05-071-11/+15
| | | | | | | | | | | | | | | We can avoid allocating empty shared caches and avoid unecessary check of cache->limit. We save some memory. We avoid bringing into CPU cache unecessary cache lines. All accesses to l3->shared are already checking NULL pointers so this patch is safe. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Christoph Lameter <clameter@engr.sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* SLAB: use num_possible_cpus() in enable_cpucache()Eric Dumazet2007-05-071-3/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | The existing comment in mm/slab.c is *perfect*, so I reproduce it : /* * CPU bound tasks (e.g. network routing) can exhibit cpu bound * allocation behaviour: Most allocs on one cpu, most free operations * on another cpu. For these cases, an efficient object passing between * cpus is necessary. This is provided by a shared array. The array * replaces Bonwick's magazine layer. * On uniprocessor, it's functionally equivalent (but less efficient) * to a larger limit. Thus disabled by default. */ As most shiped linux kernels are now compiled with CONFIG_SMP, there is no way a preprocessor #if can detect if the machine is UP or SMP. Better to use num_possible_cpus(). This means on UP we allocate a 'size=0 shared array', to be more efficient. Another patch can later avoid the allocations of 'empty shared arrays', to save some memory. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Acked-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* readahead: code cleanupJan Kara2007-05-073-20/+21
| | | | | | | | | | | | | | Rename file_ra_state.prev_page to prev_index and file_ra_state.offset to prev_offset. Also update of prev_index in do_generic_mapping_read() is now moved close to the update of prev_offset. [wfg@mail.ustc.edu.cn: fix it] Signed-off-by: Jan Kara <jack@suse.cz> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: WU Fengguang <wfg@mail.ustc.edu.cn> Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* readahead: improve heuristic detecting sequential readsJan Kara2007-05-073-3/+10
| | | | | | | | | | | | | | Introduce ra.offset and store in it an offset where the previous read ended. This way we can detect whether reads are really sequential (and thus we should not mark the page as accessed repeatedly) or whether they are random and just happen to be in the same page (and the page should really be marked accessed again). Signed-off-by: Jan Kara <jack@suse.cz> Acked-by: Nick Piggin <nickpiggin@yahoo.com.au> Cc: WU Fengguang <wfg@mail.ustc.edu.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* smaps: add clear_refs file to clear referenceDavid Rientjes2007-05-074-31/+116
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Adds /proc/pid/clear_refs. When any non-zero number is written to this file, pte_mkold() and ClearPageReferenced() is called for each pte and its corresponding page, respectively, in that task's VMAs. This file is only writable by the user who owns the task. It is now possible to measure _approximately_ how much memory a task is using by clearing the reference bits with echo 1 > /proc/pid/clear_refs and checking the reference count for each VMA from the /proc/pid/smaps output at a measured time interval. For example, to observe the approximate change in memory footprint for a task, write a script that clears the references (echo 1 > /proc/pid/clear_refs), sleeps, and then greps for Pgs_Referenced and extracts the size in kB. Add the sizes for each VMA together for the total referenced footprint. Moments later, repeat the process and observe the difference. For example, using an efficient Mozilla: accumulated time referenced memory ---------------- ----------------- 0 s 408 kB 1 s 408 kB 2 s 556 kB 3 s 1028 kB 4 s 872 kB 5 s 1956 kB 6 s 416 kB 7 s 1560 kB 8 s 2336 kB 9 s 1044 kB 10 s 416 kB This is a valuable tool to get an approximate measurement of the memory footprint for a task. Cc: Hugh Dickins <hugh@veritas.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by: David Rientjes <rientjes@google.com> [akpm@linux-foundation.org: build fixes] [mpm@selenic.com: rename for_each_pmd] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* smaps: add pages referenced count to smapsDavid Rientjes2007-05-071-7/+13
| | | | | | | | | | | | | | | | | Adds an additional unsigned long field to struct mem_size_stats called 'referenced'. For each pte walked in the smaps code, this field is incremented by PAGE_SIZE if it has pte-reference bits. An additional line was added to the /proc/pid/smaps output for each VMA to indicate how many pages within it are currently marked as referenced or accessed. Cc: Hugh Dickins <hugh@veritas.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* smaps: extract pmd walker from smaps codeDavid Rientjes2007-05-071-27/+42
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Extracts the pmd walker from smaps-specific code in fs/proc/task_mmu.c. The new struct pmd_walker includes the struct vm_area_struct of the memory to walk over. Iteration begins at the vma->vm_start and completes at vma->vm_end. A pointer to another data structure may be stored in the private field such as struct mem_size_stats, which acts as the smaps accumulator. For each pmd in the VMA, the action function is called with a pointer to its struct vm_area_struct, a pointer to the pmd_t, its start and end addresses, and the private field. The interface for walking pmd's in a VMA for fs/proc/task_mmu.c is now: void for_each_pmd(struct vm_area_struct *vma, void (*action)(struct vm_area_struct *vma, pmd_t *pmd, unsigned long addr, unsigned long end, void *private), void *private); Since the pmd walker is now extracted from the smaps code, smaps_one_pmd() is invoked for each pmd in the VMA. Its behavior and efficiency is identical to the existing implementation. Cc: Hugh Dickins <hugh@veritas.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* i386: use pte_update_defer in ptep_test_and_clear_{dirty,young}Zachary Amsden2007-05-071-20/+18
| | | | | | | | | | | | | | | | | | If you actually clear the bit, you need to: + pte_update_defer(vma->vm_mm, addr, ptep); The reason is, when updating PTEs, the hypervisor must be notified. Using atomic operations to do this is fine for all hypervisors I am aware of. However, for hypervisors which shadow page tables, if these PTE modifications are not trapped, you need a post-modification call to fulfill the update of the shadow page table. Acked-by: Zachary Amsden <zach@vmware.com> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* i386: add ptep_test_and_clear_{dirty,young}David Rientjes2007-05-071-8/+17
| | | | | | | | | | | | | | | | | | Add ptep_test_and_clear_{dirty,young} to i386. They advertise that they have it and there is at least one place where it needs to be called without the page table lock: to clear the accessed bit on write to /proc/pid/clear_refs. ptep_clear_flush_{dirty,young} are updated to use the new functions. The overall net effect to current users of ptep_clear_flush_{dirty,young} is that we introduce an additional branch. Cc: Hugh Dickins <hugh@veritas.com> Cc: Ingo Molnar <mingo@redhat.com> Signed-off-by: David Rientjes <rientjes@google.com> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Add unitialized_var() macro for suppressing gcc warningsBorislav Petkov2007-05-074-1/+15
| | | | | | | | | | | | | | | | | | | | | | | | | Introduce a macro for suppressing gcc from generating a warning about a probable uninitialized state of a variable. Example: - spinlock_t *ptl; + spinlock_t *uninitialized_var(ptl); Not a happy solution, but those warnings are obnoxious. - Using the usual pointlessly-set-it-to-zero approach wastes several bytes of text. - Using a macro means we can (hopefully) do something else if gcc changes cause the `x = x' hack to stop working - Using a macro means that people who are worried about hiding true bugs can easily turn it off. Signed-off-by: Borislav Petkov <bbpetkov@yahoo.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: simplify filemap_nopageNick Piggin2007-05-071-24/+0
| | | | | | | | | | | | Identical block is duplicated twice: contrary to the comment, we have been re-reading the page *twice* in filemap_nopage rather than once. If any retry logic or anything is needed, it belongs in lower levels anyway. Only retry once. Linus agrees. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* add pfn_valid_within helper for sub-MAX_ORDER hole detectionAndy Whitcroft2007-05-072-6/+14
| | | | | | | | | | | | | | | | | | | Generally we work under the assumption that memory the mem_map array is contigious and valid out to MAX_ORDER_NR_PAGES block of pages, ie. that if we have validated any page within this MAX_ORDER_NR_PAGES block we need not check any other. This is not true when CONFIG_HOLES_IN_ZONE is set and we must check each and every reference we make from a pfn. Add a pfn_valid_within() helper which should be used when scanning pages within a MAX_ORDER_NR_PAGES block when we have already checked the validility of the block normally with pfn_valid(). This can then be optimised away when we do not have holes within a MAX_ORDER_NR_PAGES block of pages. Signed-off-by: Andy Whitcroft <apw@shadowen.org> Acked-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Bob Picco <bob.picco@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/slab.c: proper prototypesAdrian Bunk2007-05-072-2/+3
| | | | | | | | Add proper prototypes in include/linux/slab.h. Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Introduce CONFIG_HAS_DMAHeiko Carstens2007-05-074-4/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | Architectures that don't support DMA can say so by adding a config NO_DMA to their Kconfig file. This will prevent compilation of some dma specific driver code. Also dma-mapping-broken.h isn't needed anymore on at least s390. This avoids compilation and linking of otherwise dead/broken code. Other architectures that include dma-mapping-broken.h are arm26, h8300, m68k, m68knommu and v850. If these could be converted as well we could get rid of the header file. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> "John W. Linville" <linville@tuxdriver.com> Cc: Kyle McMartin <kyle@parisc-linux.org> Cc: <James.Bottomley@SteelEye.com> Cc: Tejun Heo <htejun@gmail.com> Cc: Jeff Garzik <jeff@garzik.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: <geert@linux-m68k.org> Cc: <zippel@linux-m68k.org> Cc: <spyro@f2s.com> Cc: <uclinux-v850@lsi.nec.co.jp> Cc: <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* allow oom_adj of saintly processesJoshua N Pritikin2007-05-071-2/+4
| | | | | | | | | | | If the badness of a process is zero then oom_adj>0 has no effect. This patch makes sure that the oom_adj shift actually increases badness points appropriately. Signed-off-by: Joshua N. Pritikin <jpritikin@pobox.com> Cc: Andrea Arcangeli <andrea@novell.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs: buffer don't PageUptodate without page lockedNick Piggin2007-05-071-10/+1
| | | | | | | | | | | | | | | | __block_write_full_page is calling SetPageUptodate without the page locked. This is unusual, but not incorrect, as PG_writeback is still set. However the next patch will require that SetPageUptodate always be called with the page locked. Simply don't bother setting the page uptodate in this case (it is unusual that the write path does such a thing anyway). Instead just leave it to the read side to bring the page uptodate when it notices that all buffers are uptodate. Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: make read_cache_page synchronousNick Piggin2007-05-0724-146/+71
| | | | | | | | | | | | | | | | Ensure pages are uptodate after returning from read_cache_page, which allows us to cut out most of the filesystem-internal PageUptodate calls. I didn't have a great look down the call chains, but this appears to fixes 7 possible use-before uptodate in hfs, 2 in hfsplus, 1 in jfs, a few in ecryptfs, 1 in jffs2, and a possible cleared data overwritten with readpage in block2mtd. All depending on whether the filler is async and/or can return with a !uptodate page. Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* slab: ensure cache_alloc_refill terminatesPekka Enberg2007-05-071-0/+8
| | | | | | | | | | | | | If slab->inuse is corrupted, cache_alloc_refill can enter an infinite loop as detailed by Michael Richardson in the following post: <http://lkml.org/lkml/2007/2/16/292>. This adds a BUG_ON to catch those cases. Cc: Michael Richardson <mcr@sandelman.ca> Acked-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: remove gcc workaroundNick Piggin2007-05-072-12/+18
| | | | | | | | | | | | Minimum gcc version is 3.2 now. However, with likely profiling, even modern gcc versions cannot always eliminate the call. Replace the placeholder functions with the more conventional empty static inlines, which should be optimal for everyone. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* proper prototype for hugetlb_get_unmapped_area()Adrian Bunk2007-05-072-4/+7
| | | | | | | | | | Add a proper prototype for hugetlb_get_unmapped_area() in include/linux/hugetlb.h. Signed-off-by: Adrian Bunk <bunk@stusta.de> Acked-by: William Irwin <wli@holomorphy.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Use ZVC counters to establish exact size of dirtyable pagesChristoph Lameter2007-05-071-10/+40
| | | | | | | | | | | | | | | | | | | | | | | | | | | We can use the global ZVC counters to establish the exact size of the LRU and the free pages. This allows a more accurate determination of the dirty ratio. This patch will fix the broken ratio calculations if large amounts of memory are allocated to huge pags or other consumers that do not put the pages on to the LRU. Notes: - I did not add NR_SLAB_RECLAIMABLE to the calculation of the dirtyable pages. Those may be reclaimable but they are at this point not dirtyable. If NR_SLAB_RECLAIMABLE would be considered then a huge number of reclaimable pages would stop writeback from occurring. - This patch used to be in mm as the last one in a series of patches. It was removed when Linus updated the treatment of highmem because there was a conflict. I updated the patch to follow Linus' approach. This patch is neede to fulfill the claims made in the beginning of the patchset that is now in Linus' tree. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Safer nr_node_ids and nr_node_ids determination and initial valuesChristoph Lameter2007-05-074-9/+9
| | | | | | | | | | | | | | | | | | The nr_cpu_ids value is currently only calculated in smp_init. However, it may be needed before (SLUB needs it on kmem_cache_init!) and other kernel components may also want to allocate dynamically sized per cpu array before smp_init. So move the determination of possible cpus into sched_init() where we already loop over all possible cpus early in boot. Also initialize both nr_node_ids and nr_cpu_ids with the highest value they could take. If we have accidental users before these values are determined then the current valud of 0 may cause too small per cpu and per node arrays to be allocated. If it is set to the maximum possible then we only waste some memory for early boot users. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Add apply_to_page_range() which applies a function to a pte rangeJeremy Fitzhardinge2007-05-072-0/+99
| | | | | | | | | | | | | | | | | | | | | | | | Add a new mm function apply_to_page_range() which applies a given function to every pte in a given virtual address range in a given mm structure. This is a generic alternative to cut-and-pasting the Linux idiomatic pagetable walking code in every place that a sequence of PTEs must be accessed. Although this interface is intended to be useful in a wide range of situations, it is currently used specifically by several Xen subsystems, for example: to ensure that pagetables have been allocated for a virtual address range, and to construct batched special pagetable update requests to map I/O memory (in ioremap()). [akpm@linux-foundation.org: fix warning, unpleasantly] Signed-off-by: Ian Pratt <ian.pratt@xensource.com> Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk> Signed-off-by: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Christoph Lameter <clameter@sgi.com> Cc: Matt Mackall <mpm@waste.org> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Serial: serial_core, use pr_debugJiri Slaby2007-05-071-12/+5
| | | | | | | | | serial_core, use pr_debug Signed-off-by: Jiri Slaby <jirislaby@gmail.com> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* MPSC serial driver tx lockingDave Jiang2007-05-071-1/+24
| | | | | | | | | | | | | | | | | | | | The MPSC serial driver assumes that interrupt is always on to pick up the DMA transmit ops that aren't submitted while the DMA engine is active. However when irqs are off for a period of time such as operations under kernel crash dump console messages do not show up due to additional DMA ops are being dropped. This makes console writes to process through all the tx DMAs queued up before submitting a new request. Also, the current locking mechanism does not protect the hardware registers and ring buffer when a printk is done during the serial write operations. The additional per port transmit lock provides a finer granular locking and protects registers being clobbered while printks are nested within UART writes. Signed-off-by: Dave Jiang <djiang@mvista.com> Signed-off-by: Mark A. Greer <mgreer@mvista.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* serial: define FIXED_PORT flag for serial_coreDavid Gibson2007-05-074-11/+18
| | | | | | | | | | | | | | | | | | | | | | | | At present, the serial core always allows setserial in userspace to change the port address, irq and base clock of any serial port. That makes sense for legacy ISA ports, but not for (say) embedded ns16550 compatible serial ports at peculiar addresses. In these cases, the kernel code configuring the ports must know exactly where they are, and their clocking arrangements (which can be unusual on embedded boards). It doesn't make sense for userspace to change these settings. Therefore, this patch defines a UPF_FIXED_PORT flag for the uart_port structure. If this flag is set when the serial port is configured, any attempts to alter the port's type, io address, irq or base clock with setserial are ignored. In addition this patch uses the new flag for on-chip serial ports probed in arch/powerpc/kernel/legacy_serial.c, and for other hard-wired serial ports probed by drivers/serial/of_serial.c. Signed-off-by: David Gibson <dwg@au1.ibm.com> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* RM9000 serial driverThomas Koeller2007-05-074-13/+95
| | | | | | | | | | | | | | Add support for the integrated serial ports of the MIPS RM9122 processor and its relatives. The patch also does some whitespace cleanup. [akpm@linux-foundation.org: cleanups] Signed-off-by: Thomas Koeller <thomas.koeller@baslerweb.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
generated by cgit (git 2.34.1) at 2024-09-21 11:40:06 +0000