diff options
Diffstat (limited to 'drivers/xen/tmem.c')
| -rw-r--r-- | drivers/xen/tmem.c | 170 |
1 files changed, 158 insertions, 12 deletions
diff --git a/drivers/xen/tmem.c b/drivers/xen/tmem.c index 816a44959ef..d369965e8f8 100644 --- a/drivers/xen/tmem.c +++ b/drivers/xen/tmem.c @@ -1,7 +1,7 @@ /* * Xen implementation for transcendent memory (tmem) * - * Copyright (C) 2009-2010 Oracle Corp. All rights reserved. + * Copyright (C) 2009-2011 Oracle Corp. All rights reserved. * Author: Dan Magenheimer */ @@ -9,8 +9,14 @@ #include <linux/types.h> #include <linux/init.h> #include <linux/pagemap.h> +#include <linux/module.h> #include <linux/cleancache.h> +/* temporary ifdef until include/linux/frontswap.h is upstream */ +#ifdef CONFIG_FRONTSWAP +#include <linux/frontswap.h> +#endif + #include <xen/xen.h> #include <xen/interface/xen.h> #include <asm/xen/hypercall.h> @@ -122,14 +128,8 @@ static int xen_tmem_flush_object(u32 pool_id, struct tmem_oid oid) return xen_tmem_op(TMEM_FLUSH_OBJECT, pool_id, oid, 0, 0, 0, 0, 0); } -static int xen_tmem_destroy_pool(u32 pool_id) -{ - struct tmem_oid oid = { { 0 } }; - - return xen_tmem_op(TMEM_DESTROY_POOL, pool_id, oid, 0, 0, 0, 0, 0); -} - -int tmem_enabled; +int tmem_enabled __read_mostly; +EXPORT_SYMBOL(tmem_enabled); static int __init enable_tmem(char *s) { @@ -139,6 +139,14 @@ static int __init enable_tmem(char *s) __setup("tmem", enable_tmem); +#ifdef CONFIG_CLEANCACHE +static int xen_tmem_destroy_pool(u32 pool_id) +{ + struct tmem_oid oid = { { 0 } }; + + return xen_tmem_op(TMEM_DESTROY_POOL, pool_id, oid, 0, 0, 0, 0, 0); +} + /* cleancache ops */ static void tmem_cleancache_put_page(int pool, struct cleancache_filekey key, @@ -240,18 +248,156 @@ static struct cleancache_ops tmem_cleancache_ops = { .init_shared_fs = tmem_cleancache_init_shared_fs, .init_fs = tmem_cleancache_init_fs }; +#endif -static int __init xen_tmem_init(void) +#ifdef CONFIG_FRONTSWAP +/* frontswap tmem operations */ + +/* a single tmem poolid is used for all frontswap "types" (swapfiles) */ +static int tmem_frontswap_poolid; + +/* + * Swizzling increases objects per swaptype, increasing tmem concurrency + * for heavy swaploads. Later, larger nr_cpus -> larger SWIZ_BITS + */ +#define SWIZ_BITS 4 +#define SWIZ_MASK ((1 << SWIZ_BITS) - 1) +#define _oswiz(_type, _ind) ((_type << SWIZ_BITS) | (_ind & SWIZ_MASK)) +#define iswiz(_ind) (_ind >> SWIZ_BITS) + +static inline struct tmem_oid oswiz(unsigned type, u32 ind) +{ + struct tmem_oid oid = { .oid = { 0 } }; + oid.oid[0] = _oswiz(type, ind); + return oid; +} + +/* returns 0 if the page was successfully put into frontswap, -1 if not */ +static int tmem_frontswap_put_page(unsigned type, pgoff_t offset, + struct page *page) +{ + u64 ind64 = (u64)offset; + u32 ind = (u32)offset; + unsigned long pfn = page_to_pfn(page); + int pool = tmem_frontswap_poolid; + int ret; + + if (pool < 0) + return -1; + if (ind64 != ind) + return -1; + mb(); /* ensure page is quiescent; tmem may address it with an alias */ + ret = xen_tmem_put_page(pool, oswiz(type, ind), iswiz(ind), pfn); + /* translate Xen tmem return values to linux semantics */ + if (ret == 1) + return 0; + else + return -1; +} + +/* + * returns 0 if the page was successfully gotten from frontswap, -1 if + * was not present (should never happen!) + */ +static int tmem_frontswap_get_page(unsigned type, pgoff_t offset, + struct page *page) { - struct cleancache_ops old_ops; + u64 ind64 = (u64)offset; + u32 ind = (u32)offset; + unsigned long pfn = page_to_pfn(page); + int pool = tmem_frontswap_poolid; + int ret; + + if (pool < 0) + return -1; + if (ind64 != ind) + return -1; + ret = xen_tmem_get_page(pool, oswiz(type, ind), iswiz(ind), pfn); + /* translate Xen tmem return values to linux semantics */ + if (ret == 1) + return 0; + else + return -1; +} +/* flush a single page from frontswap */ +static void tmem_frontswap_flush_page(unsigned type, pgoff_t offset) +{ + u64 ind64 = (u64)offset; + u32 ind = (u32)offset; + int pool = tmem_frontswap_poolid; + + if (pool < 0) + return; + if (ind64 != ind) + return; + (void) xen_tmem_flush_page(pool, oswiz(type, ind), iswiz(ind)); +} + +/* flush all pages from the passed swaptype */ +static void tmem_frontswap_flush_area(unsigned type) +{ + int pool = tmem_frontswap_poolid; + int ind; + + if (pool < 0) + return; + for (ind = SWIZ_MASK; ind >= 0; ind--) + (void)xen_tmem_flush_object(pool, oswiz(type, ind)); +} + +static void tmem_frontswap_init(unsigned ignored) +{ + struct tmem_pool_uuid private = TMEM_POOL_PRIVATE_UUID; + + /* a single tmem poolid is used for all frontswap "types" (swapfiles) */ + if (tmem_frontswap_poolid < 0) + tmem_frontswap_poolid = + xen_tmem_new_pool(private, TMEM_POOL_PERSIST, PAGE_SIZE); +} + +static int __initdata use_frontswap = 1; + +static int __init no_frontswap(char *s) +{ + use_frontswap = 0; + return 1; +} + +__setup("nofrontswap", no_frontswap); + +static struct frontswap_ops tmem_frontswap_ops = { + .put_page = tmem_frontswap_put_page, + .get_page = tmem_frontswap_get_page, + .flush_page = tmem_frontswap_flush_page, + .flush_area = tmem_frontswap_flush_area, + .init = tmem_frontswap_init +}; +#endif + +static int __init xen_tmem_init(void) +{ if (!xen_domain()) return 0; +#ifdef CONFIG_FRONTSWAP + if (tmem_enabled && use_frontswap) { + char *s = ""; + struct frontswap_ops old_ops = + frontswap_register_ops(&tmem_frontswap_ops); + + tmem_frontswap_poolid = -1; + if (old_ops.init != NULL) + s = " (WARNING: frontswap_ops overridden)"; + printk(KERN_INFO "frontswap enabled, RAM provided by " + "Xen Transcendent Memory\n"); + } +#endif #ifdef CONFIG_CLEANCACHE BUG_ON(sizeof(struct cleancache_filekey) != sizeof(struct tmem_oid)); if (tmem_enabled && use_cleancache) { char *s = ""; - old_ops = cleancache_register_ops(&tmem_cleancache_ops); + struct cleancache_ops old_ops = + cleancache_register_ops(&tmem_cleancache_ops); if (old_ops.init_fs != NULL) s = " (WARNING: cleancache_ops overridden)"; printk(KERN_INFO "cleancache enabled, RAM provided by " |