407 lines
9.9 KiB
C
407 lines
9.9 KiB
C
/*
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* Xen implementation for transcendent memory (tmem)
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*
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* Copyright (C) 2009-2011 Oracle Corp. All rights reserved.
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* Author: Dan Magenheimer
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*/
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#include <linux/kernel.h>
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#include <linux/types.h>
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#include <linux/init.h>
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#include <linux/pagemap.h>
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#include <linux/cleancache.h>
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/* temporary ifdef until include/linux/frontswap.h is upstream */
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#ifdef CONFIG_FRONTSWAP
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#include <linux/frontswap.h>
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#endif
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#include <xen/xen.h>
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#include <xen/interface/xen.h>
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#include <asm/xen/hypercall.h>
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#include <asm/xen/page.h>
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#include <asm/xen/hypervisor.h>
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#include <xen/tmem.h>
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#define TMEM_CONTROL 0
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#define TMEM_NEW_POOL 1
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#define TMEM_DESTROY_POOL 2
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#define TMEM_NEW_PAGE 3
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#define TMEM_PUT_PAGE 4
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#define TMEM_GET_PAGE 5
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#define TMEM_FLUSH_PAGE 6
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#define TMEM_FLUSH_OBJECT 7
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#define TMEM_READ 8
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#define TMEM_WRITE 9
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#define TMEM_XCHG 10
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/* Bits for HYPERVISOR_tmem_op(TMEM_NEW_POOL) */
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#define TMEM_POOL_PERSIST 1
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#define TMEM_POOL_SHARED 2
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#define TMEM_POOL_PAGESIZE_SHIFT 4
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#define TMEM_VERSION_SHIFT 24
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struct tmem_pool_uuid {
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u64 uuid_lo;
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u64 uuid_hi;
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};
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struct tmem_oid {
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u64 oid[3];
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};
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#define TMEM_POOL_PRIVATE_UUID { 0, 0 }
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/* flags for tmem_ops.new_pool */
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#define TMEM_POOL_PERSIST 1
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#define TMEM_POOL_SHARED 2
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/* xen tmem foundation ops/hypercalls */
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static inline int xen_tmem_op(u32 tmem_cmd, u32 tmem_pool, struct tmem_oid oid,
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u32 index, unsigned long gmfn, u32 tmem_offset, u32 pfn_offset, u32 len)
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{
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struct tmem_op op;
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int rc = 0;
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op.cmd = tmem_cmd;
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op.pool_id = tmem_pool;
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op.u.gen.oid[0] = oid.oid[0];
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op.u.gen.oid[1] = oid.oid[1];
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op.u.gen.oid[2] = oid.oid[2];
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op.u.gen.index = index;
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op.u.gen.tmem_offset = tmem_offset;
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op.u.gen.pfn_offset = pfn_offset;
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op.u.gen.len = len;
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set_xen_guest_handle(op.u.gen.gmfn, (void *)gmfn);
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rc = HYPERVISOR_tmem_op(&op);
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return rc;
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}
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static int xen_tmem_new_pool(struct tmem_pool_uuid uuid,
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u32 flags, unsigned long pagesize)
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{
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struct tmem_op op;
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int rc = 0, pageshift;
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for (pageshift = 0; pagesize != 1; pageshift++)
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pagesize >>= 1;
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flags |= (pageshift - 12) << TMEM_POOL_PAGESIZE_SHIFT;
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flags |= TMEM_SPEC_VERSION << TMEM_VERSION_SHIFT;
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op.cmd = TMEM_NEW_POOL;
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op.u.new.uuid[0] = uuid.uuid_lo;
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op.u.new.uuid[1] = uuid.uuid_hi;
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op.u.new.flags = flags;
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rc = HYPERVISOR_tmem_op(&op);
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return rc;
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}
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/* xen generic tmem ops */
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static int xen_tmem_put_page(u32 pool_id, struct tmem_oid oid,
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u32 index, unsigned long pfn)
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{
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unsigned long gmfn = xen_pv_domain() ? pfn_to_mfn(pfn) : pfn;
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return xen_tmem_op(TMEM_PUT_PAGE, pool_id, oid, index,
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gmfn, 0, 0, 0);
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}
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static int xen_tmem_get_page(u32 pool_id, struct tmem_oid oid,
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u32 index, unsigned long pfn)
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{
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unsigned long gmfn = xen_pv_domain() ? pfn_to_mfn(pfn) : pfn;
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return xen_tmem_op(TMEM_GET_PAGE, pool_id, oid, index,
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gmfn, 0, 0, 0);
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}
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static int xen_tmem_flush_page(u32 pool_id, struct tmem_oid oid, u32 index)
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{
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return xen_tmem_op(TMEM_FLUSH_PAGE, pool_id, oid, index,
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0, 0, 0, 0);
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}
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static int xen_tmem_flush_object(u32 pool_id, struct tmem_oid oid)
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{
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return xen_tmem_op(TMEM_FLUSH_OBJECT, pool_id, oid, 0, 0, 0, 0, 0);
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}
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bool __read_mostly tmem_enabled = false;
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static int __init enable_tmem(char *s)
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{
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tmem_enabled = true;
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return 1;
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}
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__setup("tmem", enable_tmem);
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#ifdef CONFIG_CLEANCACHE
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static int xen_tmem_destroy_pool(u32 pool_id)
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{
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struct tmem_oid oid = { { 0 } };
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return xen_tmem_op(TMEM_DESTROY_POOL, pool_id, oid, 0, 0, 0, 0, 0);
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}
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/* cleancache ops */
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static void tmem_cleancache_put_page(int pool, struct cleancache_filekey key,
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pgoff_t index, struct page *page)
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{
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u32 ind = (u32) index;
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struct tmem_oid oid = *(struct tmem_oid *)&key;
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unsigned long pfn = page_to_pfn(page);
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if (pool < 0)
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return;
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if (ind != index)
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return;
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mb(); /* ensure page is quiescent; tmem may address it with an alias */
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(void)xen_tmem_put_page((u32)pool, oid, ind, pfn);
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}
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static int tmem_cleancache_get_page(int pool, struct cleancache_filekey key,
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pgoff_t index, struct page *page)
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{
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u32 ind = (u32) index;
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struct tmem_oid oid = *(struct tmem_oid *)&key;
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unsigned long pfn = page_to_pfn(page);
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int ret;
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/* translate return values to linux semantics */
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if (pool < 0)
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return -1;
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if (ind != index)
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return -1;
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ret = xen_tmem_get_page((u32)pool, oid, ind, pfn);
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if (ret == 1)
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return 0;
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else
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return -1;
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}
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static void tmem_cleancache_flush_page(int pool, struct cleancache_filekey key,
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pgoff_t index)
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{
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u32 ind = (u32) index;
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struct tmem_oid oid = *(struct tmem_oid *)&key;
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if (pool < 0)
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return;
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if (ind != index)
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return;
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(void)xen_tmem_flush_page((u32)pool, oid, ind);
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}
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static void tmem_cleancache_flush_inode(int pool, struct cleancache_filekey key)
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{
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struct tmem_oid oid = *(struct tmem_oid *)&key;
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if (pool < 0)
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return;
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(void)xen_tmem_flush_object((u32)pool, oid);
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}
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static void tmem_cleancache_flush_fs(int pool)
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{
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if (pool < 0)
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return;
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(void)xen_tmem_destroy_pool((u32)pool);
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}
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static int tmem_cleancache_init_fs(size_t pagesize)
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{
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struct tmem_pool_uuid uuid_private = TMEM_POOL_PRIVATE_UUID;
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return xen_tmem_new_pool(uuid_private, 0, pagesize);
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}
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static int tmem_cleancache_init_shared_fs(char *uuid, size_t pagesize)
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{
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struct tmem_pool_uuid shared_uuid;
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shared_uuid.uuid_lo = *(u64 *)uuid;
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shared_uuid.uuid_hi = *(u64 *)(&uuid[8]);
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return xen_tmem_new_pool(shared_uuid, TMEM_POOL_SHARED, pagesize);
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}
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static bool __initdata use_cleancache = true;
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static int __init no_cleancache(char *s)
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{
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use_cleancache = false;
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return 1;
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}
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__setup("nocleancache", no_cleancache);
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static struct cleancache_ops __initdata tmem_cleancache_ops = {
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.put_page = tmem_cleancache_put_page,
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.get_page = tmem_cleancache_get_page,
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.invalidate_page = tmem_cleancache_flush_page,
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.invalidate_inode = tmem_cleancache_flush_inode,
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.invalidate_fs = tmem_cleancache_flush_fs,
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.init_shared_fs = tmem_cleancache_init_shared_fs,
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.init_fs = tmem_cleancache_init_fs
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};
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#endif
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#ifdef CONFIG_FRONTSWAP
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/* frontswap tmem operations */
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/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
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static int tmem_frontswap_poolid;
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/*
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* Swizzling increases objects per swaptype, increasing tmem concurrency
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* for heavy swaploads. Later, larger nr_cpus -> larger SWIZ_BITS
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*/
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#define SWIZ_BITS 4
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#define SWIZ_MASK ((1 << SWIZ_BITS) - 1)
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#define _oswiz(_type, _ind) ((_type << SWIZ_BITS) | (_ind & SWIZ_MASK))
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#define iswiz(_ind) (_ind >> SWIZ_BITS)
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static inline struct tmem_oid oswiz(unsigned type, u32 ind)
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{
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struct tmem_oid oid = { .oid = { 0 } };
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oid.oid[0] = _oswiz(type, ind);
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return oid;
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}
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/* returns 0 if the page was successfully put into frontswap, -1 if not */
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static int tmem_frontswap_store(unsigned type, pgoff_t offset,
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struct page *page)
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{
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u64 ind64 = (u64)offset;
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u32 ind = (u32)offset;
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unsigned long pfn = page_to_pfn(page);
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int pool = tmem_frontswap_poolid;
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int ret;
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if (pool < 0)
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return -1;
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if (ind64 != ind)
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return -1;
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mb(); /* ensure page is quiescent; tmem may address it with an alias */
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ret = xen_tmem_put_page(pool, oswiz(type, ind), iswiz(ind), pfn);
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/* translate Xen tmem return values to linux semantics */
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if (ret == 1)
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return 0;
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else
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return -1;
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}
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/*
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* returns 0 if the page was successfully gotten from frontswap, -1 if
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* was not present (should never happen!)
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*/
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static int tmem_frontswap_load(unsigned type, pgoff_t offset,
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struct page *page)
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{
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u64 ind64 = (u64)offset;
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u32 ind = (u32)offset;
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unsigned long pfn = page_to_pfn(page);
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int pool = tmem_frontswap_poolid;
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int ret;
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if (pool < 0)
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return -1;
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if (ind64 != ind)
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return -1;
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ret = xen_tmem_get_page(pool, oswiz(type, ind), iswiz(ind), pfn);
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/* translate Xen tmem return values to linux semantics */
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if (ret == 1)
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return 0;
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else
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return -1;
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}
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/* flush a single page from frontswap */
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static void tmem_frontswap_flush_page(unsigned type, pgoff_t offset)
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{
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u64 ind64 = (u64)offset;
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u32 ind = (u32)offset;
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int pool = tmem_frontswap_poolid;
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if (pool < 0)
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return;
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if (ind64 != ind)
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return;
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(void) xen_tmem_flush_page(pool, oswiz(type, ind), iswiz(ind));
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}
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/* flush all pages from the passed swaptype */
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static void tmem_frontswap_flush_area(unsigned type)
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{
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int pool = tmem_frontswap_poolid;
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int ind;
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if (pool < 0)
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return;
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for (ind = SWIZ_MASK; ind >= 0; ind--)
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(void)xen_tmem_flush_object(pool, oswiz(type, ind));
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}
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static void tmem_frontswap_init(unsigned ignored)
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{
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struct tmem_pool_uuid private = TMEM_POOL_PRIVATE_UUID;
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/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
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if (tmem_frontswap_poolid < 0)
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tmem_frontswap_poolid =
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xen_tmem_new_pool(private, TMEM_POOL_PERSIST, PAGE_SIZE);
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}
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static bool __initdata use_frontswap = true;
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static int __init no_frontswap(char *s)
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{
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use_frontswap = false;
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return 1;
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}
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__setup("nofrontswap", no_frontswap);
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static struct frontswap_ops __initdata tmem_frontswap_ops = {
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.store = tmem_frontswap_store,
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.load = tmem_frontswap_load,
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.invalidate_page = tmem_frontswap_flush_page,
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.invalidate_area = tmem_frontswap_flush_area,
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.init = tmem_frontswap_init
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};
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#endif
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static int __init xen_tmem_init(void)
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{
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if (!xen_domain())
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return 0;
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#ifdef CONFIG_FRONTSWAP
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if (tmem_enabled && use_frontswap) {
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char *s = "";
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struct frontswap_ops old_ops =
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frontswap_register_ops(&tmem_frontswap_ops);
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tmem_frontswap_poolid = -1;
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if (old_ops.init != NULL)
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s = " (WARNING: frontswap_ops overridden)";
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printk(KERN_INFO "frontswap enabled, RAM provided by "
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"Xen Transcendent Memory\n");
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}
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#endif
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#ifdef CONFIG_CLEANCACHE
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BUG_ON(sizeof(struct cleancache_filekey) != sizeof(struct tmem_oid));
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if (tmem_enabled && use_cleancache) {
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char *s = "";
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struct cleancache_ops old_ops =
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cleancache_register_ops(&tmem_cleancache_ops);
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if (old_ops.init_fs != NULL)
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s = " (WARNING: cleancache_ops overridden)";
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printk(KERN_INFO "cleancache enabled, RAM provided by "
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"Xen Transcendent Memory%s\n", s);
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}
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#endif
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return 0;
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}
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module_init(xen_tmem_init)
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