staging: zcache: enable zcache to be built/loaded as a module

Allow zcache to be built/loaded as a module.  Note runtime dependency
disallows loading if cleancache/frontswap lazy initialization patches
are not present.  Zsmalloc support has not yet been merged into zcache
but, once merged, could now easily be selected via a module_param.

If built-in (not built as a module), the original mechanism of enabling
via a kernel boot parameter is retained, but this should be considered
deprecated.

Note that module unload is explicitly not yet supported.

Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
[v1: Rebased with different order of patches]
[v2: Removed [CLEANCACHE|FRONTSWAP]_HAS_LAZY_INIT ifdef]
[v3: Rebased on top of ramster->zcache move]
[v4: Redid the Makefile]
[v5: s/ZCACHE2/ZCACHE/]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Bob Liu <lliubbo@gmail.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Andor Daam <andor.daam@googlemail.com>
Cc: Florian Schmaus <fschmaus@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Stefan Hengelein <ilendir@googlemail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/staging/zcache/Kconfig b/drivers/staging/zcache/Kconfig
index 05e87a1e5d93ca8d76d3b8e6b3e637ece1bce21e..2d7b2da3b9e0a2e5d707f6db9a502882c5c3c650 100644 (file)
--- a/drivers/staging/zcache/Kconfig
+++ b/drivers/staging/zcache/Kconfig
@@ -1,5 +1,5 @@
 config ZCACHE
-       bool "Dynamic compression of swap pages and clean pagecache pages"
+       tristate "Dynamic compression of swap pages and clean pagecache pages"
        depends on CRYPTO=y && SWAP=y && CLEANCACHE && FRONTSWAP
        select CRYPTO_LZO
        default n
@@ -19,8 +19,8 @@ config ZCACHE_DEBUG
          how zcache is doing. You probably want to set this to 'N'.
 
 config RAMSTER
-       bool "Cross-machine RAM capacity sharing, aka peer-to-peer tmem"
-       depends on CONFIGFS_FS=y && SYSFS=y && !HIGHMEM && ZCACHE=y
+       tristate "Cross-machine RAM capacity sharing, aka peer-to-peer tmem"
+       depends on CONFIGFS_FS=y && SYSFS=y && !HIGHMEM && ZCACHE
        depends on NET
        # must ensure struct page is 8-byte aligned
        select HAVE_ALIGNED_STRUCT_PAGE if !64BIT

diff --git a/drivers/staging/zcache/tmem.c b/drivers/staging/zcache/tmem.c
index a2b7e03b606279b76fc7ea5f1d39ddcafe967433..d7e51e4152ebe45f9760b1fa05cf33c6042a9a87 100644 (file)
--- a/drivers/staging/zcache/tmem.c
+++ b/drivers/staging/zcache/tmem.c
@@ -35,7 +35,8 @@
 #include <linux/list.h>
 #include <linux/spinlock.h>
 #include <linux/atomic.h>
-#ifdef CONFIG_RAMSTER
+#include <linux/export.h>
+#if defined(CONFIG_RAMSTER) || defined(CONFIG_RAMSTER_MODULE)
 #include <linux/delay.h>
 #endif
 
@@ -641,6 +642,7 @@ void *tmem_localify_get_pampd(struct tmem_pool *pool, struct tmem_oid *oidp,
        /* note, hashbucket remains locked */
        return pampd;
 }
+EXPORT_SYMBOL_GPL(tmem_localify_get_pampd);
 
 void tmem_localify_finish(struct tmem_obj *obj, uint32_t index,
                          void *pampd, void *saved_hb, bool delete)
@@ -658,6 +660,7 @@ void tmem_localify_finish(struct tmem_obj *obj, uint32_t index,
        }
        spin_unlock(&hb->lock);
 }
+EXPORT_SYMBOL_GPL(tmem_localify_finish);
 
 /*
  * For ramster only.  Helper function to support asynchronous tmem_get.
@@ -719,6 +722,7 @@ out:
        spin_unlock(&hb->lock);
        return ret;
 }
+EXPORT_SYMBOL_GPL(tmem_replace);
 #endif
 
 /*

diff --git a/drivers/staging/zcache/tmem.h b/drivers/staging/zcache/tmem.h
index adbe5a8f28aa3caa1440cbe0c274c3c3bc73783d..d128ce290f1f8b808fc5d5e1ea8122dce6ac0da9 100644 (file)
--- a/drivers/staging/zcache/tmem.h
+++ b/drivers/staging/zcache/tmem.h
@@ -126,7 +126,7 @@ static inline unsigned tmem_oid_hash(struct tmem_oid *oidp)
                                TMEM_HASH_BUCKET_BITS);
 }
 
-#ifdef CONFIG_RAMSTER
+#if defined(CONFIG_RAMSTER) || defined(CONFIG_RAMSTER_MODULE)
 struct tmem_xhandle {
        uint8_t client_id;
        uint8_t xh_data_cksum;
@@ -171,7 +171,7 @@ struct tmem_obj {
        unsigned int objnode_tree_height;
        unsigned long objnode_count;
        long pampd_count;
-#ifdef CONFIG_RAMSTER
+#if defined(CONFIG_RAMSTER) || defined(CONFIG_RAMSTER_MODULE)
        /*
         * for current design of ramster, all pages belonging to
         * an object reside on the same remotenode and extra is
@@ -215,7 +215,7 @@ struct tmem_pamops {
                                uint32_t);
        void (*free)(void *, struct tmem_pool *,
                                struct tmem_oid *, uint32_t, bool);
-#ifdef CONFIG_RAMSTER
+#if defined(CONFIG_RAMSTER) || defined(CONFIG_RAMSTER_MODULE)
        void (*new_obj)(struct tmem_obj *);
        void (*free_obj)(struct tmem_pool *, struct tmem_obj *, bool);
        void *(*repatriate_preload)(void *, struct tmem_pool *,
@@ -247,7 +247,7 @@ extern int tmem_flush_page(struct tmem_pool *, struct tmem_oid *,
 extern int tmem_flush_object(struct tmem_pool *, struct tmem_oid *);
 extern int tmem_destroy_pool(struct tmem_pool *);
 extern void tmem_new_pool(struct tmem_pool *, uint32_t);
-#ifdef CONFIG_RAMSTER
+#if defined(CONFIG_RAMSTER) || defined(CONFIG_RAMSTER_MODULE)
 extern int tmem_replace(struct tmem_pool *, struct tmem_oid *, uint32_t index,
                        void *);
 extern void *tmem_localify_get_pampd(struct tmem_pool *, struct tmem_oid *,

diff --git a/drivers/staging/zcache/zcache-main.c b/drivers/staging/zcache/zcache-main.c
index 326c2ea17c38bd433f58a8e83e3fb44b04852233..522cb8e5514269b12eaee3a8875ba6f241c64dad 100644 (file)
--- a/drivers/staging/zcache/zcache-main.c
+++ b/drivers/staging/zcache/zcache-main.c
@@ -37,8 +37,10 @@
 #include "debug.h"
 #ifdef CONFIG_RAMSTER
 static bool ramster_enabled __read_mostly;
+static int disable_frontswap_selfshrink;
 #else
 #define ramster_enabled false
+#define disable_frontswap_selfshrink 0
 #endif
 
 #ifndef __PG_WAS_ACTIVE
@@ -81,8 +83,12 @@ static char *namestr __read_mostly = "zcache";
        (__GFP_FS | __GFP_NORETRY | __GFP_NOWARN | __GFP_NOMEMALLOC)
 
 /* crypto API for zcache  */
+#ifdef CONFIG_ZCACHE_MODULE
+static char *zcache_comp_name = "lzo";
+#else
 #define ZCACHE_COMP_NAME_SZ CRYPTO_MAX_ALG_NAME
 static char zcache_comp_name[ZCACHE_COMP_NAME_SZ] __read_mostly;
+#endif
 static struct crypto_comp * __percpu *zcache_comp_pcpu_tfms __read_mostly;
 
 enum comp_op {
@@ -1721,6 +1727,7 @@ struct frontswap_ops *zcache_frontswap_register_ops(void)
  * OR NOTHING HAPPENS!
  */
 
+#ifndef CONFIG_ZCACHE_MODULE
 static int __init enable_zcache(char *s)
 {
        zcache_enabled = true;
@@ -1787,18 +1794,27 @@ static int __init enable_zcache_compressor(char *s)
        return 1;
 }
 __setup("zcache=", enable_zcache_compressor);
+#endif
 
 
-static int __init zcache_comp_init(void)
+static int zcache_comp_init(void)
 {
        int ret = 0;
 
        /* check crypto algorithm */
+#ifdef CONFIG_ZCACHE_MODULE
+       ret = crypto_has_comp(zcache_comp_name, 0, 0);
+       if (!ret) {
+               ret = -1;
+               goto out;
+       }
+#else
        if (*zcache_comp_name != '\0') {
                ret = crypto_has_comp(zcache_comp_name, 0, 0);
                if (!ret)
                        pr_info("zcache: %s not supported\n",
                                        zcache_comp_name);
+               goto out;
        }
        if (!ret)
                strcpy(zcache_comp_name, "lzo");
@@ -1807,6 +1823,7 @@ static int __init zcache_comp_init(void)
                ret = 1;
                goto out;
        }
+#endif
        pr_info("zcache: using %s compressor\n", zcache_comp_name);
 
        /* alloc percpu transforms */
@@ -1818,10 +1835,13 @@ out:
        return ret;
 }
 
-static int __init zcache_init(void)
+static int zcache_init(void)
 {
        int ret = 0;
 
+#ifdef CONFIG_ZCACHE_MODULE
+       zcache_enabled = 1;
+#endif
        if (ramster_enabled) {
                namestr = "ramster";
                ramster_register_pamops(&zcache_pamops);
@@ -1894,9 +1914,28 @@ static int __init zcache_init(void)
        }
        if (ramster_enabled)
                ramster_init(!disable_cleancache, !disable_frontswap,
-                               frontswap_has_exclusive_gets, false);
+                               frontswap_has_exclusive_gets,
+                               !disable_frontswap_selfshrink);
 out:
        return ret;
 }
 
+#ifdef CONFIG_ZCACHE_MODULE
+#ifdef CONFIG_RAMSTER
+module_param(ramster_enabled, int, S_IRUGO);
+module_param(disable_frontswap_selfshrink, int, S_IRUGO);
+#endif
+module_param(disable_cleancache, int, S_IRUGO);
+module_param(disable_frontswap, int, S_IRUGO);
+#ifdef FRONTSWAP_HAS_EXCLUSIVE_GETS
+module_param(frontswap_has_exclusive_gets, bool, S_IRUGO);
+#endif
+module_param(disable_frontswap_ignore_nonactive, int, S_IRUGO);
+module_param(zcache_comp_name, charp, S_IRUGO);
+module_init(zcache_init);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Dan Magenheimer <dan.magenheimer@oracle.com>");
+MODULE_DESCRIPTION("In-kernel compression of cleancache/frontswap pages");
+#else
 late_initcall(zcache_init);
+#endif

diff --git a/drivers/staging/zcache/zcache.h b/drivers/staging/zcache/zcache.h
index 81722b33b0872ac8a165f983af2cc1dd6494d8e8..849120095e7987de954d35d3eeebfc4aa6674d45 100644 (file)
--- a/drivers/staging/zcache/zcache.h
+++ b/drivers/staging/zcache/zcache.h
@@ -39,7 +39,7 @@ extern int zcache_flush_page(int, int, struct tmem_oid *, uint32_t);
 extern int zcache_flush_object(int, int, struct tmem_oid *);
 extern void zcache_decompress_to_page(char *, unsigned int, struct page *);
 
-#ifdef CONFIG_RAMSTER
+#if defined(CONFIG_RAMSTER) || defined(CONFIG_RAMSTER_MODULE)
 extern void *zcache_pampd_create(char *, unsigned int, bool, int,
                                struct tmem_handle *);
 int zcache_autocreate_pool(unsigned int cli_id, unsigned int pool_id, bool eph);