On Sat, May 24, 2014 at 03:06:06PM -0400, Dan Streetman wrote: > Add zpool api. > > zpool provides an interface for memory storage, typically of compressed > memory. Users can select what backend to use; currently the only > implementations are zbud, a low density implementation with up to > two compressed pages per storage page, and zsmalloc, a higher density > implementation with multiple compressed pages per storage page. > > Signed-off-by: Dan Streetman <ddstreet@xxxxxxxx> > Cc: Seth Jennings <sjennings@xxxxxxxxxxxxxx> > Cc: Minchan Kim <minchan@xxxxxxxxxx> > Cc: Nitin Gupta <ngupta@xxxxxxxxxx> > Cc: Weijie Yang <weijie.yang@xxxxxxxxxxx> > --- > > Note this patch set is against the mmotm tree at > git://git.cmpxchg.org/linux-mmotm.git > This patch may need context changes to the -next or other trees. > > Changes since v2 : https://lkml.org/lkml/2014/5/7/733 > -Remove hardcoded zbud/zsmalloc implementations > -Add driver (un)register functions > > Changes since v1 https://lkml.org/lkml/2014/4/19/101 > -add some pr_info() during creation and pr_err() on errors > -remove zpool code to call zs_shrink(), since zsmalloc shrinking > was removed from this patchset > -remove fallback; only specified pool type will be tried > -pr_fmt() is defined in zpool to prefix zpool: in any pr_XXX() calls > > > include/linux/zpool.h | 214 ++++++++++++++++++++++++++++++++++++++++++++++++++ > mm/Kconfig | 41 ++++++---- > mm/Makefile | 1 + > mm/zpool.c | 197 ++++++++++++++++++++++++++++++++++++++++++++++ > 4 files changed, 436 insertions(+), 17 deletions(-) > create mode 100644 include/linux/zpool.h > create mode 100644 mm/zpool.c > > diff --git a/include/linux/zpool.h b/include/linux/zpool.h > new file mode 100644 > index 0000000..699ac9b > --- /dev/null > +++ b/include/linux/zpool.h > @@ -0,0 +1,214 @@ > +/* > + * 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 > +}; > + > +/** > + * zpool_create_pool() - Create a new zpool > + * @type The type of the zpool to create (e.g. zbud, zsmalloc) > + * @flags What GFP flags should be used when the zpool allocates memory. > + * @ops The optional ops callback. > + * > + * This creates a new zpool of the specified type. The zpool will use the > + * given flags when allocating any memory. If the ops param is NULL, then > + * the created zpool will not be shrinkable. > + * > + * Returns: New zpool on success, NULL on failure. > + */ > +struct zpool *zpool_create_pool(char *type, gfp_t flags, > + struct zpool_ops *ops); > + > +/** > + * zpool_get_type() - Get the type of the zpool > + * @pool The zpool to check > + * > + * This returns the type of the pool. > + * > + * Returns: The type of zpool. > + */ > +char *zpool_get_type(struct zpool *pool); > + > +/** > + * zpool_destroy_pool() - Destroy a zpool > + * @pool The zpool to destroy. > + * > + * This destroys an existing zpool. The zpool should not be in use. > + */ > +void zpool_destroy_pool(struct zpool *pool); > + > +/** > + * zpool_malloc() - Allocate memory > + * @pool The zpool to allocate from. > + * @size The amount of memory to allocate. > + * @handle Pointer to the handle to set > + * > + * This allocates the requested amount of memory from the pool. > + * The provided @handle will be set to the allocated object handle. > + * > + * Returns: 0 on success, negative value on error. > + */ > +int zpool_malloc(struct zpool *pool, size_t size, unsigned long *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. > + */ > +void zpool_free(struct zpool *pool, unsigned long handle); > + > +/** > + * zpool_shrink() - Shrink the pool size > + * @pool The zpool to shrink. > + * @size The minimum amount to shrink the pool. > + * > + * 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. > + * > + * Returns: 0 on success, negative value on error/failure. > + */ > +int zpool_shrink(struct zpool *pool, size_t size); This should take a number of pages to be reclaimed, not a size. The user can evict their own object to reclaim a certain number of bytes from the pool. What the user can't do is reclaim a page since it is not aware of the arrangement of the stored objects in the memory pages. Also in patch 5/6 of six I see: - if (zbud_reclaim_page(zswap_pool, 8)) { + if (zpool_shrink(zswap_pool, PAGE_SIZE)) { but then in 4/6 I see: +int zbud_zpool_shrink(void *pool, size_t size) +{ + return zbud_reclaim_page(pool, 8); +} That is why it didn't completely explode on you since the zbud logic is still reclaiming pages. > + > +/** > + * 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 implemenation 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. Multiple handles should not be mapped > + * concurrently on a cpu. > + * > + * Returns: A pointer to the handle's mapped memory area. > + */ > +void *zpool_map_handle(struct zpool *pool, unsigned long handle, > + enum zpool_mapmode mm); > + > +/** > + * 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 implemenation 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 *pool, unsigned long 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 *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 list_head list; > + > + void *(*create)(gfp_t gfp, struct zpool_ops *ops); > + void (*destroy)(void *pool); > + > + int (*malloc)(void *pool, size_t size, unsigned long *handle); > + void (*free)(void *pool, unsigned long handle); > + > + int (*shrink)(void *pool, size_t size); > + > + void *(*map)(void *pool, unsigned long handle, > + enum zpool_mapmode mm); > + void (*unmap)(void *pool, unsigned long handle); > + > + u64 (*total_size)(void *pool); > +}; > + > +/** > + * zpool_register_driver() - register a zpool implementation. > + * @driver: driver to register > + */ > +void zpool_register_driver(struct zpool_driver *driver); > + > +/** > + * zpool_unregister_driver() - unregister a zpool implementation. > + * @driver: driver to unregister. > + */ > +void zpool_unregister_driver(struct zpool_driver *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); > + > +#endif > diff --git a/mm/Kconfig b/mm/Kconfig > index 7511b4a..00f7720 100644 > --- a/mm/Kconfig > +++ b/mm/Kconfig > @@ -515,15 +515,17 @@ config CMA_DEBUG > processing calls such as dma_alloc_from_contiguous(). > This option does not affect warning and error messages. > > -config ZBUD > - tristate > - default n > +config MEM_SOFT_DIRTY > + bool "Track memory changes" > + depends on CHECKPOINT_RESTORE && HAVE_ARCH_SOFT_DIRTY && PROC_FS > + select PROC_PAGE_MONITOR > 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. > + This option enables memory changes tracking by introducing a > + soft-dirty bit on pte-s. This bit it set when someone writes > + 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 ZSWAP > bool "Compressed cache for swap pages (EXPERIMENTAL)" > @@ -545,17 +547,22 @@ config ZSWAP > they have not be fully explored on the large set of potential > configurations and workloads that exist. > > -config MEM_SOFT_DIRTY > - bool "Track memory changes" > - depends on CHECKPOINT_RESTORE && HAVE_ARCH_SOFT_DIRTY && PROC_FS > - select PROC_PAGE_MONITOR > +config ZPOOL > + tristate "Common API for compressed memory storage" > + default n > help > - This option enables memory changes tracking by introducing a > - soft-dirty bit on pte-s. This bit it set when someone writes > - into a page just as regular dirty bit, but unlike the latter > - it can be cleared by hands. > + Compressed memory storage API. This allows using either zbud or > + zsmalloc. > > - 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 > tristate "Memory allocator for compressed pages" > diff --git a/mm/Makefile b/mm/Makefile > index 2b6fff2..759db04 100644 > --- a/mm/Makefile > +++ b/mm/Makefile > @@ -61,6 +61,7 @@ obj-$(CONFIG_DEBUG_KMEMLEAK_TEST) += kmemleak-test.o > obj-$(CONFIG_CLEANCACHE) += cleancache.o > obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o > obj-$(CONFIG_PAGE_OWNER) += pageowner.o > +obj-$(CONFIG_ZPOOL) += zpool.o > obj-$(CONFIG_ZBUD) += zbud.o > obj-$(CONFIG_ZSMALLOC) += zsmalloc.o > obj-$(CONFIG_GENERIC_EARLY_IOREMAP) += early_ioremap.o > diff --git a/mm/zpool.c b/mm/zpool.c > new file mode 100644 > index 0000000..89ed71f > --- /dev/null > +++ b/mm/zpool.c > @@ -0,0 +1,197 @@ > +/* > + * 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); > + > +void zpool_register_driver(struct zpool_driver *driver) > +{ > + spin_lock(&drivers_lock); > + list_add(&driver->list, &drivers_head); > + spin_unlock(&drivers_lock); > +} > +EXPORT_SYMBOL(zpool_register_driver); > + > +void zpool_unregister_driver(struct zpool_driver *driver) > +{ > + spin_lock(&drivers_lock); > + list_del(&driver->list); > + spin_unlock(&drivers_lock); > +} > +EXPORT_SYMBOL(zpool_unregister_driver); > + > +int zpool_evict(void *pool, unsigned long handle) > +{ > + struct zpool *zpool; > + > + spin_lock(&pools_lock); > + list_for_each_entry(zpool, &pools_head, list) { You can do a container_of() here: zpool = container_of(pool, struct zpool, pool); Seth > + 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; > + > + assert_spin_locked(&drivers_lock); > + list_for_each_entry(driver, &drivers_head, list) { > + if (!strcmp(driver->type, type)) > + return driver; > + } > + > + return NULL; > +} > + > +struct zpool *zpool_create_pool(char *type, gfp_t flags, > + struct zpool_ops *ops) > +{ > + struct zpool_driver *driver; > + struct zpool *zpool; > + > + pr_info("creating pool type %s\n", type); > + > + spin_lock(&drivers_lock); > + driver = zpool_get_driver(type); > + spin_unlock(&drivers_lock); > + > + if (!driver) { > + request_module(type); > + spin_lock(&drivers_lock); > + driver = zpool_get_driver(type); > + spin_unlock(&drivers_lock); > + } > + > + if (!driver) { > + pr_err("no driver for type %s\n", type); > + return NULL; > + } > + > + zpool = kmalloc(sizeof(*zpool), GFP_KERNEL); > + if (!zpool) { > + pr_err("couldn't create zpool - out of memory\n"); > + return NULL; > + } > + > + zpool->type = driver->type; > + zpool->driver = driver; > + zpool->pool = driver->create(flags, ops); > + zpool->ops = ops; > + > + if (!zpool->pool) { > + pr_err("couldn't create %s pool\n", type); > + 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; > +} > + > +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); > + kfree(zpool); > +} > + > +char *zpool_get_type(struct zpool *zpool) > +{ > + return zpool->type; > +} > + > +int zpool_malloc(struct zpool *zpool, size_t size, unsigned long *handle) > +{ > + return zpool->driver->malloc(zpool->pool, size, handle); > +} > + > +void zpool_free(struct zpool *zpool, unsigned long handle) > +{ > + zpool->driver->free(zpool->pool, handle); > +} > + > +int zpool_shrink(struct zpool *zpool, size_t size) > +{ > + return zpool->driver->shrink(zpool->pool, size); > +} > + > +void *zpool_map_handle(struct zpool *zpool, unsigned long handle, > + enum zpool_mapmode mapmode) > +{ > + return zpool->driver->map(zpool->pool, handle, mapmode); > +} > + > +void zpool_unmap_handle(struct zpool *zpool, unsigned long handle) > +{ > + zpool->driver->unmap(zpool->pool, handle); > +} > + > +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@xxxxxxxx>"); > +MODULE_DESCRIPTION("Common API for compressed memory storage"); 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