/* * 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(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 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; 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");