mm/zpool: implement common zpool api to zbud/zsmalloc (af8d417a) · Commits · e / devices / android_kernel_teracube_emerald

include/linux/zpool.h

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			/*
			* zpool memory storage api
			*
			* Copyright (C) 2014 Dan Streetman
			*
			* This is a common frontend for the zbud and zsmalloc memory
			* storage pool implementations. Typically, this is used to
			* store compressed memory.
			*/

			#ifndef _ZPOOL_H_
			#define _ZPOOL_H_

			struct zpool;

			struct zpool_ops {
			int (evict)(struct zpool pool, unsigned long handle);
			};

			/*
			* Control how a handle is mapped. It will be ignored if the
			* implementation does not support it. Its use is optional.
			* Note that this does not refer to memory protection, it
			* refers to how the memory will be copied in/out if copying
			* is necessary during mapping; read-write is the safest as
			* it copies the existing memory in on map, and copies the
			* changed memory back out on unmap. Write-only does not copy
			* in the memory and should only be used for initialization.
			* If in doubt, use ZPOOL_MM_DEFAULT which is read-write.
			*/
			enum zpool_mapmode {
			ZPOOL_MM_RW, /* normal read-write mapping */
			ZPOOL_MM_RO, /* read-only (no copy-out at unmap time) */
			ZPOOL_MM_WO, /* write-only (no copy-in at map time) */

			ZPOOL_MM_DEFAULT = ZPOOL_MM_RW
			};

			struct zpool zpool_create_pool(char type, gfp_t gfp, struct zpool_ops *ops);

			char zpool_get_type(struct zpool pool);

			void zpool_destroy_pool(struct zpool *pool);

			int zpool_malloc(struct zpool *pool, size_t size, gfp_t gfp,
			unsigned long *handle);

			void zpool_free(struct zpool *pool, unsigned long handle);

			int zpool_shrink(struct zpool *pool, unsigned int pages,
			unsigned int *reclaimed);

			void zpool_map_handle(struct zpool pool, unsigned long handle,
			enum zpool_mapmode mm);

			void zpool_unmap_handle(struct zpool *pool, unsigned long handle);

			u64 zpool_get_total_size(struct zpool *pool);


			/**
			* struct zpool_driver - driver implementation for zpool
			* @type: name of the driver.
			* @list: entry in the list of zpool drivers.
			* @create: create a new pool.
			* @destroy: destroy a pool.
			* @malloc: allocate mem from a pool.
			* @free: free mem from a pool.
			* @shrink: shrink the pool.
			* @map: map a handle.
			* @unmap: unmap a handle.
			* @total_size: get total size of a pool.
			*
			* This is created by a zpool implementation and registered
			* with zpool.
			*/
			struct zpool_driver {
			char *type;
			struct module *owner;
			atomic_t refcount;
			struct list_head list;

			void (create)(gfp_t gfp, struct zpool_ops *ops);
			void (destroy)(void pool);

			int (malloc)(void pool, size_t size, gfp_t gfp,
			unsigned long *handle);
			void (free)(void pool, unsigned long handle);

			int (shrink)(void pool, unsigned int pages,
			unsigned int *reclaimed);

			void (map)(void *pool, unsigned long handle,
			enum zpool_mapmode mm);
			void (unmap)(void pool, unsigned long handle);

			u64 (total_size)(void pool);
			};

			void zpool_register_driver(struct zpool_driver *driver);

			int zpool_unregister_driver(struct zpool_driver *driver);

			int zpool_evict(void *pool, unsigned long handle);

			#endif

mm/Kconfig

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	@@ -519,15 +519,17 @@ config CMA_AREAS

	If unsure, leave the default value "7".		If unsure, leave the default value "7".

	config ZBUD		config MEM_SOFT_DIRTY
	tristate		bool "Track memory changes"
	default n		depends on CHECKPOINT_RESTORE && HAVE_ARCH_SOFT_DIRTY && PROC_FS
			select PROC_PAGE_MONITOR
	help		help
	A special purpose allocator for storing compressed pages.		This option enables memory changes tracking by introducing a
	It is designed to store up to two compressed pages per physical		soft-dirty bit on pte-s. This bit it set when someone writes
	page. While this design limits storage density, it has simple and		into a page just as regular dirty bit, but unlike the latter
	deterministic reclaim properties that make it preferable to a higher		it can be cleared by hands.
	density approach when reclaim will be used.
			See Documentation/vm/soft-dirty.txt for more details.

	config ZSWAP		config ZSWAP
	bool "Compressed cache for swap pages (EXPERIMENTAL)"		bool "Compressed cache for swap pages (EXPERIMENTAL)"
	@@ -549,17 +551,22 @@ config ZSWAP
	they have not be fully explored on the large set of potential		they have not be fully explored on the large set of potential
	configurations and workloads that exist.		configurations and workloads that exist.

	config MEM_SOFT_DIRTY		config ZPOOL
	bool "Track memory changes"		tristate "Common API for compressed memory storage"
	depends on CHECKPOINT_RESTORE && HAVE_ARCH_SOFT_DIRTY && PROC_FS		default n
	select PROC_PAGE_MONITOR
	help		help
	This option enables memory changes tracking by introducing a		Compressed memory storage API. This allows using either zbud or
	soft-dirty bit on pte-s. This bit it set when someone writes		zsmalloc.
	into a page just as regular dirty bit, but unlike the latter
	it can be cleared by hands.

	See Documentation/vm/soft-dirty.txt for more details.		config ZBUD
			tristate "Low density storage for compressed pages"
			default n
			help
			A special purpose allocator for storing compressed pages.
			It is designed to store up to two compressed pages per physical
			page. While this design limits storage density, it has simple and
			deterministic reclaim properties that make it preferable to a higher
			density approach when reclaim will be used.

	config ZSMALLOC		config ZSMALLOC
	tristate "Memory allocator for compressed pages"		tristate "Memory allocator for compressed pages"

mm/Makefile

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	@@ -59,6 +59,7 @@ obj-$(CONFIG_DEBUG_KMEMLEAK) += kmemleak.o
	obj-$(CONFIG_DEBUG_KMEMLEAK_TEST) += kmemleak-test.o		obj-$(CONFIG_DEBUG_KMEMLEAK_TEST) += kmemleak-test.o
	obj-$(CONFIG_CLEANCACHE) += cleancache.o		obj-$(CONFIG_CLEANCACHE) += cleancache.o
	obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o		obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o
			obj-$(CONFIG_ZPOOL) += zpool.o
	obj-$(CONFIG_ZBUD) += zbud.o		obj-$(CONFIG_ZBUD) += zbud.o
	obj-$(CONFIG_ZSMALLOC) += zsmalloc.o		obj-$(CONFIG_ZSMALLOC) += zsmalloc.o
	obj-$(CONFIG_GENERIC_EARLY_IOREMAP) += early_ioremap.o		obj-$(CONFIG_GENERIC_EARLY_IOREMAP) += early_ioremap.o

mm/zpool.c

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			/*
			* zpool memory storage api
			*
			* Copyright (C) 2014 Dan Streetman
			*
			* This is a common frontend for memory storage pool implementations.
			* Typically, this is used to store compressed memory.
			*/

			#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

			#include <linux/list.h>
			#include <linux/types.h>
			#include <linux/mm.h>
			#include <linux/slab.h>
			#include <linux/spinlock.h>
			#include <linux/module.h>
			#include <linux/zpool.h>

			struct zpool {
			char *type;

			struct zpool_driver *driver;
			void *pool;
			struct zpool_ops *ops;

			struct list_head list;
			};

			static LIST_HEAD(drivers_head);
			static DEFINE_SPINLOCK(drivers_lock);

			static LIST_HEAD(pools_head);
			static DEFINE_SPINLOCK(pools_lock);

			/**
			* zpool_register_driver() - register a zpool implementation.
			* @driver: driver to register
			*/
			void zpool_register_driver(struct zpool_driver *driver)
			{
			spin_lock(&drivers_lock);
			atomic_set(&driver->refcount, 0);
			list_add(&driver->list, &drivers_head);
			spin_unlock(&drivers_lock);
			}
			EXPORT_SYMBOL(zpool_register_driver);

			/**
			* zpool_unregister_driver() - unregister a zpool implementation.
			* @driver: driver to unregister.
			*
			* Module usage counting is used to prevent using a driver
			* while/after unloading, so if this is called from module
			* exit function, this should never fail; if called from
			* other than the module exit function, and this returns
			* failure, the driver is in use and must remain available.
			*/
			int zpool_unregister_driver(struct zpool_driver *driver)
			{
			int ret = 0, refcount;

			spin_lock(&drivers_lock);
			refcount = atomic_read(&driver->refcount);
			WARN_ON(refcount < 0);
			if (refcount > 0)
			ret = -EBUSY;
			else
			list_del(&driver->list);
			spin_unlock(&drivers_lock);

			return ret;
			}
			EXPORT_SYMBOL(zpool_unregister_driver);

			/**
			* zpool_evict() - evict callback from a zpool implementation.
			* @pool: pool to evict from.
			* @handle: handle to evict.
			*
			* This can be used by zpool implementations to call the
			* user's evict zpool_ops struct evict callback.
			*/
			int zpool_evict(void *pool, unsigned long handle)
			{
			struct zpool *zpool;

			spin_lock(&pools_lock);
			list_for_each_entry(zpool, &pools_head, list) {
			if (zpool->pool == pool) {
			spin_unlock(&pools_lock);
			if (!zpool->ops \|\| !zpool->ops->evict)
			return -EINVAL;
			return zpool->ops->evict(zpool, handle);
			}
			}
			spin_unlock(&pools_lock);

			return -ENOENT;
			}
			EXPORT_SYMBOL(zpool_evict);

			static struct zpool_driver zpool_get_driver(char type)
			{
			struct zpool_driver *driver;

			spin_lock(&drivers_lock);
			list_for_each_entry(driver, &drivers_head, list) {
			if (!strcmp(driver->type, type)) {
			bool got = try_module_get(driver->owner);

			if (got)
			atomic_inc(&driver->refcount);
			spin_unlock(&drivers_lock);
			return got ? driver : NULL;
			}
			}

			spin_unlock(&drivers_lock);
			return NULL;
			}

			static void zpool_put_driver(struct zpool_driver *driver)
			{
			atomic_dec(&driver->refcount);
			module_put(driver->owner);
			}

			/**
			* zpool_create_pool() - Create a new zpool
			* @type The type of the zpool to create (e.g. zbud, zsmalloc)
			* @gfp The GFP flags to use when allocating the pool.
			* @ops The optional ops callback.
			*
			* This creates a new zpool of the specified type. The gfp flags will be
			* used when allocating memory, if the implementation supports it. If the
			* ops param is NULL, then the created zpool will not be shrinkable.
			*
			* Implementations must guarantee this to be thread-safe.
			*
			* Returns: New zpool on success, NULL on failure.
			*/
			struct zpool zpool_create_pool(char type, gfp_t gfp, struct zpool_ops *ops)
			{
			struct zpool_driver *driver;
			struct zpool *zpool;

			pr_info("creating pool type %s\n", type);

			driver = zpool_get_driver(type);

			if (!driver) {
			request_module(type);
			driver = zpool_get_driver(type);
			}

			if (!driver) {
			pr_err("no driver for type %s\n", type);
			return NULL;
			}

			zpool = kmalloc(sizeof(*zpool), gfp);
			if (!zpool) {
			pr_err("couldn't create zpool - out of memory\n");
			zpool_put_driver(driver);
			return NULL;
			}

			zpool->type = driver->type;
			zpool->driver = driver;
			zpool->pool = driver->create(gfp, ops);
			zpool->ops = ops;

			if (!zpool->pool) {
			pr_err("couldn't create %s pool\n", type);
			zpool_put_driver(driver);
			kfree(zpool);
			return NULL;
			}

			pr_info("created %s pool\n", type);

			spin_lock(&pools_lock);
			list_add(&zpool->list, &pools_head);
			spin_unlock(&pools_lock);

			return zpool;
			}

			/**
			* zpool_destroy_pool() - Destroy a zpool
			* @pool The zpool to destroy.
			*
			* Implementations must guarantee this to be thread-safe,
			* however only when destroying different pools. The same
			* pool should only be destroyed once, and should not be used
			* after it is destroyed.
			*
			* This destroys an existing zpool. The zpool should not be in use.
			*/
			void zpool_destroy_pool(struct zpool *zpool)
			{
			pr_info("destroying pool type %s\n", zpool->type);

			spin_lock(&pools_lock);
			list_del(&zpool->list);
			spin_unlock(&pools_lock);
			zpool->driver->destroy(zpool->pool);
			zpool_put_driver(zpool->driver);
			kfree(zpool);
			}

			/**
			* zpool_get_type() - Get the type of the zpool
			* @pool The zpool to check
			*
			* This returns the type of the pool.
			*
			* Implementations must guarantee this to be thread-safe.
			*
			* Returns: The type of zpool.
			*/
			char zpool_get_type(struct zpool zpool)
			{
			return zpool->type;
			}

			/**
			* zpool_malloc() - Allocate memory
			* @pool The zpool to allocate from.
			* @size The amount of memory to allocate.
			* @gfp The GFP flags to use when allocating memory.
			* @handle Pointer to the handle to set
			*
			* This allocates the requested amount of memory from the pool.
			* The gfp flags will be used when allocating memory, if the
			* implementation supports it. The provided @handle will be
			* set to the allocated object handle.
			*
			* Implementations must guarantee this to be thread-safe.
			*
			* Returns: 0 on success, negative value on error.
			*/
			int zpool_malloc(struct zpool *zpool, size_t size, gfp_t gfp,
			unsigned long *handle)
			{
			return zpool->driver->malloc(zpool->pool, size, gfp, handle);
			}

			/**
			* zpool_free() - Free previously allocated memory
			* @pool The zpool that allocated the memory.
			* @handle The handle to the memory to free.
			*
			* This frees previously allocated memory. This does not guarantee
			* that the pool will actually free memory, only that the memory
			* in the pool will become available for use by the pool.
			*
			* Implementations must guarantee this to be thread-safe,
			* however only when freeing different handles. The same
			* handle should only be freed once, and should not be used
			* after freeing.
			*/
			void zpool_free(struct zpool *zpool, unsigned long handle)
			{
			zpool->driver->free(zpool->pool, handle);
			}

			/**
			* zpool_shrink() - Shrink the pool size
			* @pool The zpool to shrink.
			* @pages The number of pages to shrink the pool.
			* @reclaimed The number of pages successfully evicted.
			*
			* This attempts to shrink the actual memory size of the pool
			* by evicting currently used handle(s). If the pool was
			* created with no zpool_ops, or the evict call fails for any
			* of the handles, this will fail. If non-NULL, the @reclaimed
			* parameter will be set to the number of pages reclaimed,
			* which may be more than the number of pages requested.
			*
			* Implementations must guarantee this to be thread-safe.
			*
			* Returns: 0 on success, negative value on error/failure.
			*/
			int zpool_shrink(struct zpool *zpool, unsigned int pages,
			unsigned int *reclaimed)
			{
			return zpool->driver->shrink(zpool->pool, pages, reclaimed);
			}

			/**
			* zpool_map_handle() - Map a previously allocated handle into memory
			* @pool The zpool that the handle was allocated from
			* @handle The handle to map
			* @mm How the memory should be mapped
			*
			* This maps a previously allocated handle into memory. The @mm
			* param indicates to the implementation how the memory will be
			* used, i.e. read-only, write-only, read-write. If the
			* implementation does not support it, the memory will be treated
			* as read-write.
			*
			* This may hold locks, disable interrupts, and/or preemption,
			* and the zpool_unmap_handle() must be called to undo those
			* actions. The code that uses the mapped handle should complete
			* its operatons on the mapped handle memory quickly and unmap
			* as soon as possible. As the implementation may use per-cpu
			* data, multiple handles should not be mapped concurrently on
			* any cpu.
			*
			* Returns: A pointer to the handle's mapped memory area.
			*/
			void zpool_map_handle(struct zpool zpool, unsigned long handle,
			enum zpool_mapmode mapmode)
			{
			return zpool->driver->map(zpool->pool, handle, mapmode);
			}

			/**
			* zpool_unmap_handle() - Unmap a previously mapped handle
			* @pool The zpool that the handle was allocated from
			* @handle The handle to unmap
			*
			* This unmaps a previously mapped handle. Any locks or other
			* actions that the implementation took in zpool_map_handle()
			* will be undone here. The memory area returned from
			* zpool_map_handle() should no longer be used after this.
			*/
			void zpool_unmap_handle(struct zpool *zpool, unsigned long handle)
			{
			zpool->driver->unmap(zpool->pool, handle);
			}

			/**
			* zpool_get_total_size() - The total size of the pool
			* @pool The zpool to check
			*
			* This returns the total size in bytes of the pool.
			*
			* Returns: Total size of the zpool in bytes.
			*/
			u64 zpool_get_total_size(struct zpool *zpool)
			{
			return zpool->driver->total_size(zpool->pool);
			}

			static int __init init_zpool(void)
			{
			pr_info("loaded\n");
			return 0;
			}

			static void __exit exit_zpool(void)
			{
			pr_info("unloaded\n");
			}

			module_init(init_zpool);
			module_exit(exit_zpool);

			MODULE_LICENSE("GPL");
			MODULE_AUTHOR("Dan Streetman <ddstreet@ieee.org>");
			MODULE_DESCRIPTION("Common API for compressed memory storage");

mm/zsmalloc.c

+0 −1

Original line number	Original line	Diff line number	Diff line
	@@ -240,7 +240,6 @@ struct mapping_area {
	enum zs_mapmode vm_mm; /* mapping mode */		enum zs_mapmode vm_mm; /* mapping mode */
	};		};


	/* per-cpu VM mapping areas for zspage accesses that cross page boundaries */		/* per-cpu VM mapping areas for zspage accesses that cross page boundaries */
	static DEFINE_PER_CPU(struct mapping_area, zs_map_area);		static DEFINE_PER_CPU(struct mapping_area, zs_map_area);