diff options
Diffstat (limited to 'drivers/xen/tmem.c')
| -rw-r--r-- | drivers/xen/tmem.c | 418 |
1 files changed, 418 insertions, 0 deletions
diff --git a/drivers/xen/tmem.c b/drivers/xen/tmem.c new file mode 100644 index 000000000..04e7b3b29 --- /dev/null +++ b/drivers/xen/tmem.c @@ -0,0 +1,418 @@ +/* + * Xen implementation for transcendent memory (tmem) + * + * Copyright (C) 2009-2011 Oracle Corp. All rights reserved. + * Author: Dan Magenheimer + */ + +#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/types.h> +#include <linux/init.h> +#include <linux/pagemap.h> +#include <linux/cleancache.h> +#include <linux/frontswap.h> + +#include <xen/xen.h> +#include <xen/interface/xen.h> +#include <xen/page.h> +#include <asm/xen/hypercall.h> +#include <asm/xen/hypervisor.h> +#include <xen/tmem.h> + +#ifndef CONFIG_XEN_TMEM_MODULE +bool __read_mostly tmem_enabled = false; + +static int __init enable_tmem(char *s) +{ + tmem_enabled = true; + return 1; +} +__setup("tmem", enable_tmem); +#endif + +#ifdef CONFIG_CLEANCACHE +static bool cleancache __read_mostly = true; +module_param(cleancache, bool, S_IRUGO); +static bool selfballooning __read_mostly = true; +module_param(selfballooning, bool, S_IRUGO); +#endif /* CONFIG_CLEANCACHE */ + +#ifdef CONFIG_FRONTSWAP +static bool frontswap __read_mostly = true; +module_param(frontswap, bool, S_IRUGO); +#else /* CONFIG_FRONTSWAP */ +#define frontswap (0) +#endif /* CONFIG_FRONTSWAP */ + +#ifdef CONFIG_XEN_SELFBALLOONING +static bool selfshrinking __read_mostly = true; +module_param(selfshrinking, bool, S_IRUGO); +#endif /* CONFIG_XEN_SELFBALLOONING */ + +#define TMEM_CONTROL 0 +#define TMEM_NEW_POOL 1 +#define TMEM_DESTROY_POOL 2 +#define TMEM_NEW_PAGE 3 +#define TMEM_PUT_PAGE 4 +#define TMEM_GET_PAGE 5 +#define TMEM_FLUSH_PAGE 6 +#define TMEM_FLUSH_OBJECT 7 +#define TMEM_READ 8 +#define TMEM_WRITE 9 +#define TMEM_XCHG 10 + +/* Bits for HYPERVISOR_tmem_op(TMEM_NEW_POOL) */ +#define TMEM_POOL_PERSIST 1 +#define TMEM_POOL_SHARED 2 +#define TMEM_POOL_PAGESIZE_SHIFT 4 +#define TMEM_VERSION_SHIFT 24 + + +struct tmem_pool_uuid { + u64 uuid_lo; + u64 uuid_hi; +}; + +struct tmem_oid { + u64 oid[3]; +}; + +#define TMEM_POOL_PRIVATE_UUID { 0, 0 } + +/* flags for tmem_ops.new_pool */ +#define TMEM_POOL_PERSIST 1 +#define TMEM_POOL_SHARED 2 + +/* xen tmem foundation ops/hypercalls */ + +static inline int xen_tmem_op(u32 tmem_cmd, u32 tmem_pool, struct tmem_oid oid, + u32 index, unsigned long gmfn, u32 tmem_offset, u32 pfn_offset, u32 len) +{ + struct tmem_op op; + int rc = 0; + + op.cmd = tmem_cmd; + op.pool_id = tmem_pool; + op.u.gen.oid[0] = oid.oid[0]; + op.u.gen.oid[1] = oid.oid[1]; + op.u.gen.oid[2] = oid.oid[2]; + op.u.gen.index = index; + op.u.gen.tmem_offset = tmem_offset; + op.u.gen.pfn_offset = pfn_offset; + op.u.gen.len = len; + set_xen_guest_handle(op.u.gen.gmfn, (void *)gmfn); + rc = HYPERVISOR_tmem_op(&op); + return rc; +} + +static int xen_tmem_new_pool(struct tmem_pool_uuid uuid, + u32 flags, unsigned long pagesize) +{ + struct tmem_op op; + int rc = 0, pageshift; + + for (pageshift = 0; pagesize != 1; pageshift++) + pagesize >>= 1; + flags |= (pageshift - 12) << TMEM_POOL_PAGESIZE_SHIFT; + flags |= TMEM_SPEC_VERSION << TMEM_VERSION_SHIFT; + op.cmd = TMEM_NEW_POOL; + op.u.new.uuid[0] = uuid.uuid_lo; + op.u.new.uuid[1] = uuid.uuid_hi; + op.u.new.flags = flags; + rc = HYPERVISOR_tmem_op(&op); + return rc; +} + +/* xen generic tmem ops */ + +static int xen_tmem_put_page(u32 pool_id, struct tmem_oid oid, + u32 index, struct page *page) +{ + return xen_tmem_op(TMEM_PUT_PAGE, pool_id, oid, index, + xen_page_to_gfn(page), 0, 0, 0); +} + +static int xen_tmem_get_page(u32 pool_id, struct tmem_oid oid, + u32 index, struct page *page) +{ + return xen_tmem_op(TMEM_GET_PAGE, pool_id, oid, index, + xen_page_to_gfn(page), 0, 0, 0); +} + +static int xen_tmem_flush_page(u32 pool_id, struct tmem_oid oid, u32 index) +{ + return xen_tmem_op(TMEM_FLUSH_PAGE, pool_id, oid, index, + 0, 0, 0, 0); +} + +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); +} + + +#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, + pgoff_t index, struct page *page) +{ + u32 ind = (u32) index; + struct tmem_oid oid = *(struct tmem_oid *)&key; + + if (pool < 0) + return; + if (ind != index) + return; + mb(); /* ensure page is quiescent; tmem may address it with an alias */ + (void)xen_tmem_put_page((u32)pool, oid, ind, page); +} + +static int tmem_cleancache_get_page(int pool, struct cleancache_filekey key, + pgoff_t index, struct page *page) +{ + u32 ind = (u32) index; + struct tmem_oid oid = *(struct tmem_oid *)&key; + int ret; + + /* translate return values to linux semantics */ + if (pool < 0) + return -1; + if (ind != index) + return -1; + ret = xen_tmem_get_page((u32)pool, oid, ind, page); + if (ret == 1) + return 0; + else + return -1; +} + +static void tmem_cleancache_flush_page(int pool, struct cleancache_filekey key, + pgoff_t index) +{ + u32 ind = (u32) index; + struct tmem_oid oid = *(struct tmem_oid *)&key; + + if (pool < 0) + return; + if (ind != index) + return; + (void)xen_tmem_flush_page((u32)pool, oid, ind); +} + +static void tmem_cleancache_flush_inode(int pool, struct cleancache_filekey key) +{ + struct tmem_oid oid = *(struct tmem_oid *)&key; + + if (pool < 0) + return; + (void)xen_tmem_flush_object((u32)pool, oid); +} + +static void tmem_cleancache_flush_fs(int pool) +{ + if (pool < 0) + return; + (void)xen_tmem_destroy_pool((u32)pool); +} + +static int tmem_cleancache_init_fs(size_t pagesize) +{ + struct tmem_pool_uuid uuid_private = TMEM_POOL_PRIVATE_UUID; + + return xen_tmem_new_pool(uuid_private, 0, pagesize); +} + +static int tmem_cleancache_init_shared_fs(uuid_t *uuid, size_t pagesize) +{ + struct tmem_pool_uuid shared_uuid; + + shared_uuid.uuid_lo = *(u64 *)&uuid->b[0]; + shared_uuid.uuid_hi = *(u64 *)&uuid->b[8]; + return xen_tmem_new_pool(shared_uuid, TMEM_POOL_SHARED, pagesize); +} + +static const struct cleancache_ops tmem_cleancache_ops = { + .put_page = tmem_cleancache_put_page, + .get_page = tmem_cleancache_get_page, + .invalidate_page = tmem_cleancache_flush_page, + .invalidate_inode = tmem_cleancache_flush_inode, + .invalidate_fs = tmem_cleancache_flush_fs, + .init_shared_fs = tmem_cleancache_init_shared_fs, + .init_fs = tmem_cleancache_init_fs +}; +#endif + +#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_store(unsigned type, pgoff_t offset, + struct page *page) +{ + u64 ind64 = (u64)offset; + u32 ind = (u32)offset; + int pool = tmem_frontswap_poolid; + int ret; + + /* THP isn't supported */ + if (PageTransHuge(page)) + return -1; + + 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), page); + /* 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_load(unsigned type, pgoff_t offset, + struct page *page) +{ + u64 ind64 = (u64)offset; + u32 ind = (u32)offset; + 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), page); + /* 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 struct frontswap_ops tmem_frontswap_ops = { + .store = tmem_frontswap_store, + .load = tmem_frontswap_load, + .invalidate_page = tmem_frontswap_flush_page, + .invalidate_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 && frontswap) { + char *s = ""; + + tmem_frontswap_poolid = -1; + frontswap_register_ops(&tmem_frontswap_ops); + pr_info("frontswap enabled, RAM provided by Xen Transcendent Memory%s\n", + s); + } +#endif +#ifdef CONFIG_CLEANCACHE + BUILD_BUG_ON(sizeof(struct cleancache_filekey) != sizeof(struct tmem_oid)); + if (tmem_enabled && cleancache) { + int err; + + err = cleancache_register_ops(&tmem_cleancache_ops); + if (err) + pr_warn("xen-tmem: failed to enable cleancache: %d\n", + err); + else + pr_info("cleancache enabled, RAM provided by " + "Xen Transcendent Memory\n"); + } +#endif +#ifdef CONFIG_XEN_SELFBALLOONING + /* + * There is no point of driving pages to the swap system if they + * aren't going anywhere in tmem universe. + */ + if (!frontswap) { + selfshrinking = false; + selfballooning = false; + } + xen_selfballoon_init(selfballooning, selfshrinking); +#endif + return 0; +} + +module_init(xen_tmem_init) +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Dan Magenheimer <dan.magenheimer@oracle.com>"); +MODULE_DESCRIPTION("Shim to Xen transcendent memory"); |