summaryrefslogtreecommitdiff
path: root/include/linux/genalloc.h
AgeCommit message (Collapse)Author
2013-04-30genalloc: add devres support, allow to find a managed pool by devicePhilipp Zabel
This patch adds three exported functions to lib/genalloc.c: devm_gen_pool_create, dev_get_gen_pool, and of_get_named_gen_pool. devm_gen_pool_create is a managed version of gen_pool_create that keeps track of the pool via devres and allows the management code to automatically destroy it after device removal. dev_get_gen_pool retrieves the gen_pool for a given device, if it was created with devm_gen_pool_create, using devres_find. of_get_named_gen_pool retrieves the gen_pool for a given device node and property name, where the property must contain a phandle pointing to a platform device node. The corresponding platform device is then fed into dev_get_gen_pool and the resulting gen_pool is returned. [akpm@linux-foundation.org: make the of_get_named_gen_pool() stub static, fixing a zillion link errors] [akpm@linux-foundation.org: squish "struct device declared inside parameter list" warning] Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de> Acked-by: Grant Likely <grant.likely@secretlab.ca> Tested-by: Michal Simek <monstr@monstr.eu> Cc: Fabio Estevam <fabio.estevam@freescale.com> Cc: Matt Porter <mporter@ti.com> Cc: Dong Aisheng <dong.aisheng@linaro.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Rob Herring <rob.herring@calxeda.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Javier Martin <javier.martin@vista-silicon.com> Cc: Huang Shijie <shijie8@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-05genalloc: make it possible to use a custom allocation algorithmBenjamin Gaignard
Premit use of another algorithm than the default first-fit one. For example a custom algorithm could be used to manage alignment requirements. As I can't predict all the possible requirements/needs for all allocation uses cases, I add a "free" field 'void *data' to pass any needed information to the allocation function. For example 'data' could be used to handle a structure where you store the alignment, the expected memory bank, the requester device, or any information that could influence the allocation algorithm. An usage example may look like this: struct my_pool_constraints { int align; int bank; ... }; unsigned long my_custom_algo(unsigned long *map, unsigned long size, unsigned long start, unsigned int nr, void *data) { struct my_pool_constraints *constraints = data; ... deal with allocation contraints ... return the index in bitmap where perform the allocation } void create_my_pool() { struct my_pool_constraints c; struct gen_pool *pool = gen_pool_create(...); gen_pool_add(pool, ...); gen_pool_set_algo(pool, my_custom_algo, &c); } Add of best-fit algorithm function: most of the time best-fit is slower then first-fit but memory fragmentation is lower. The random buffer allocation/free tests don't show any arithmetic relation between the allocation time and fragmentation but the best-fit algorithm is sometime able to perform the allocation when the first-fit can't. This new algorithm help to remove static allocations on ESRAM, a small but fast on-chip RAM of few KB, used for high-performance uses cases like DMA linked lists, graphic accelerators, encoders/decoders. On the Ux500 (in the ARM tree) we have define 5 ESRAM banks of 128 KB each and use of static allocations becomes unmaintainable: cd arch/arm/mach-ux500 && grep -r ESRAM . ./include/mach/db8500-regs.h:/* Base address and bank offsets for ESRAM */ ./include/mach/db8500-regs.h:#define U8500_ESRAM_BASE 0x40000000 ./include/mach/db8500-regs.h:#define U8500_ESRAM_BANK_SIZE 0x00020000 ./include/mach/db8500-regs.h:#define U8500_ESRAM_BANK0 U8500_ESRAM_BASE ./include/mach/db8500-regs.h:#define U8500_ESRAM_BANK1 (U8500_ESRAM_BASE + U8500_ESRAM_BANK_SIZE) ./include/mach/db8500-regs.h:#define U8500_ESRAM_BANK2 (U8500_ESRAM_BANK1 + U8500_ESRAM_BANK_SIZE) ./include/mach/db8500-regs.h:#define U8500_ESRAM_BANK3 (U8500_ESRAM_BANK2 + U8500_ESRAM_BANK_SIZE) ./include/mach/db8500-regs.h:#define U8500_ESRAM_BANK4 (U8500_ESRAM_BANK3 + U8500_ESRAM_BANK_SIZE) ./include/mach/db8500-regs.h:#define U8500_ESRAM_DMA_LCPA_OFFSET 0x10000 ./include/mach/db8500-regs.h:#define U8500_DMA_LCPA_BASE (U8500_ESRAM_BANK0 + U8500_ESRAM_DMA_LCPA_OFFSET) ./include/mach/db8500-regs.h:#define U8500_DMA_LCLA_BASE U8500_ESRAM_BANK4 I want to use genalloc to do dynamic allocations but I need to be able to fine tune the allocation algorithm. I my case best-fit algorithm give better results than first-fit, but it will not be true for every use case. Signed-off-by: Benjamin Gaignard <benjamin.gaignard@stericsson.com> Cc: Huang Ying <ying.huang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-08-03lib, Make gen_pool memory allocator locklessHuang Ying
This version of the gen_pool memory allocator supports lockless operation. This makes it safe to use in NMI handlers and other special unblockable contexts that could otherwise deadlock on locks. This is implemented by using atomic operations and retries on any conflicts. The disadvantage is that there may be livelocks in extreme cases. For better scalability, one gen_pool allocator can be used for each CPU. The lockless operation only works if there is enough memory available. If new memory is added to the pool a lock has to be still taken. So any user relying on locklessness has to ensure that sufficient memory is preallocated. The basic atomic operation of this allocator is cmpxchg on long. On architectures that don't have NMI-safe cmpxchg implementation, the allocator can NOT be used in NMI handler. So code uses the allocator in NMI handler should depend on CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG. Signed-off-by: Huang Ying <ying.huang@intel.com> Reviewed-by: Andi Kleen <ak@linux.intel.com> Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com>
2011-05-25lib/genalloc.c: add support for specifying the physical addressJean-Christophe PLAGNIOL-VILLARD
So we can specify the virtual address as the base of the pool chunk and then get physical addresses for hardware IP. For example on at91 we will use this on spi, uart or macb Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> Cc: Nicolas Ferre <nicolas.ferre@atmel.com> Cc: Patrice VILCHEZ <patrice.vilchez@atmel.com> Cc: Jes Sorensen <jes@wildopensource.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25include/linux/genalloc.h: add multiple-inclusion guardsJean-Christophe PLAGNIOL-VILLARD
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> Cc: Nicolas Ferre <nicolas.ferre@atmel.com> Cc: Patrice VILCHEZ <patrice.vilchez@atmel.com> Cc: Jes Sorensen <jes@wildopensource.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2006-10-02[PATCH] LIB: add gen_pool_destroy()Steve Wise
Modules using the genpool allocator need to be able to destroy the data structure when unloading. Signed-off-by: Steve Wise <swise@opengridcomputing.com> Cc: Randy Dunlap <rdunlap@xenotime.net> Cc: Dean Nelson <dcn@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23[PATCH] change gen_pool allocator to not touch managed memoryDean Nelson
Modify the gen_pool allocator (lib/genalloc.c) to utilize a bitmap scheme instead of the buddy scheme. The purpose of this change is to eliminate the touching of the actual memory being allocated. Since the change modifies the interface, a change to the uncached allocator (arch/ia64/kernel/uncached.c) is also required. Both Andrey Volkov and Jes Sorenson have expressed a desire that the gen_pool allocator not write to the memory being managed. See the following: http://marc.theaimsgroup.com/?l=linux-kernel&m=113518602713125&w=2 http://marc.theaimsgroup.com/?l=linux-kernel&m=113533568827916&w=2 Signed-off-by: Dean Nelson <dcn@sgi.com> Cc: Andrey Volkov <avolkov@varma-el.com> Acked-by: Jes Sorensen <jes@trained-monkey.org> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-22[PATCH] ia64 uncached allocJes Sorensen
This patch contains the ia64 uncached page allocator and the generic allocator (genalloc). The uncached allocator was formerly part of the SN2 mspec driver but there are several other users of it so it has been split off from the driver. The generic allocator can be used by device driver to manage special memory etc. The generic allocator is based on the allocator from the sym53c8xx_2 driver. Various users on ia64 needs uncached memory. The SGI SN architecture requires it for inter-partition communication between partitions within a large NUMA cluster. The specific user for this is the XPC code. Another application is large MPI style applications which use it for synchronization, on SN this can be done using special 'fetchop' operations but it also benefits non SN hardware which may use regular uncached memory for this purpose. Performance of doing this through uncached vs cached memory is pretty substantial. This is handled by the mspec driver which I will push out in a seperate patch. Rather than creating a specific allocator for just uncached memory I came up with genalloc which is a generic purpose allocator that can be used by device drivers and other subsystems as they please. For instance to handle onboard device memory. It was derived from the sym53c7xx_2 driver's allocator which is also an example of a potential user (I am refraining from modifying sym2 right now as it seems to have been under fairly heavy development recently). On ia64 memory has various properties within a granule, ie. it isn't safe to access memory as uncached within the same granule as currently has memory accessed in cached mode. The regular system therefore doesn't utilize memory in the lower granules which is mixed in with device PAL code etc. The uncached driver walks the EFI memmap and pulls out the spill uncached pages and sticks them into the uncached pool. Only after these chunks have been utilized, will it start converting regular cached memory into uncached memory. Hence the reason for the EFI related code additions. Signed-off-by: Jes Sorensen <jes@wildopensource.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>