| /* |
| * Xen implementation for transcendent memory (tmem) |
| * |
| * Copyright (C) 2009-2011 Oracle Corp. All rights reserved. |
| * Author: Dan Magenheimer |
| */ |
| |
| #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 <asm/xen/hypercall.h> |
| #include <asm/xen/page.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); |
| #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, unsigned long pfn) |
| { |
| unsigned long gmfn = xen_pv_domain() ? pfn_to_mfn(pfn) : pfn; |
| |
| return xen_tmem_op(TMEM_PUT_PAGE, pool_id, oid, index, |
| gmfn, 0, 0, 0); |
| } |
| |
| static int xen_tmem_get_page(u32 pool_id, struct tmem_oid oid, |
| u32 index, unsigned long pfn) |
| { |
| unsigned long gmfn = xen_pv_domain() ? pfn_to_mfn(pfn) : pfn; |
| |
| return xen_tmem_op(TMEM_GET_PAGE, pool_id, oid, index, |
| gmfn, 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; |
| unsigned long pfn = page_to_pfn(page); |
| |
| 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, pfn); |
| } |
| |
| 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; |
| unsigned long pfn = page_to_pfn(page); |
| 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, pfn); |
| 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(char *uuid, size_t pagesize) |
| { |
| struct tmem_pool_uuid shared_uuid; |
| |
| shared_uuid.uuid_lo = *(u64 *)uuid; |
| shared_uuid.uuid_hi = *(u64 *)(&uuid[8]); |
| return xen_tmem_new_pool(shared_uuid, TMEM_POOL_SHARED, pagesize); |
| } |
| |
| static 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; |
| 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_load(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; |
| 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 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 xen_tmem_init(void) |
| { |
| if (!xen_domain()) |
| return 0; |
| #ifdef CONFIG_FRONTSWAP |
| if (tmem_enabled && frontswap) { |
| char *s = ""; |
| struct frontswap_ops *old_ops = |
| frontswap_register_ops(&tmem_frontswap_ops); |
| |
| tmem_frontswap_poolid = -1; |
| if (IS_ERR(old_ops) || old_ops) { |
| if (IS_ERR(old_ops)) |
| return PTR_ERR(old_ops); |
| s = " (WARNING: frontswap_ops overridden)"; |
| } |
| printk(KERN_INFO "frontswap enabled, RAM provided by " |
| "Xen Transcendent Memory%s\n", s); |
| } |
| #endif |
| #ifdef CONFIG_CLEANCACHE |
| BUG_ON(sizeof(struct cleancache_filekey) != sizeof(struct tmem_oid)); |
| if (tmem_enabled && cleancache) { |
| char *s = ""; |
| struct cleancache_ops *old_ops = |
| cleancache_register_ops(&tmem_cleancache_ops); |
| if (old_ops) |
| s = " (WARNING: cleancache_ops overridden)"; |
| printk(KERN_INFO "cleancache enabled, RAM provided by " |
| "Xen Transcendent Memory%s\n", s); |
| } |
| #endif |
| #ifdef CONFIG_XEN_SELFBALLOONING |
| 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"); |