xen: cleancache shim to Xen Transcendent Memory
This patch provides a shim between the kernel-internal cleancache API (see Documentation/mm/cleancache.txt) and the Xen Transcendent Memory ABI (see http://oss.oracle.com/projects/tmem). Xen tmem provides "hypervisor RAM" as an ephemeral page-oriented pseudo-RAM store for cleancache pages, shared cleancache pages, and frontswap pages. Tmem provides enterprise-quality concurrency, full save/restore and live migration support, compression and deduplication. A presentation showing up to 8% faster performance and up to 52% reduction in sectors read on a kernel compile workload, despite aggressive in-kernel page reclamation ("self-ballooning") can be found at: http://oss.oracle.com/projects/tmem/dist/documentation/presentations/TranscendentMemoryXenSummit2010.pdf Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Reviewed-by: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Rik Van Riel <riel@redhat.com> Cc: Jan Beulich <JBeulich@novell.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Andreas Dilger <adilger@sun.com> Cc: Ted Ts'o <tytso@mit.edu> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <joel.becker@oracle.com> Cc: Nitin Gupta <ngupta@vflare.org>
This commit is contained in:
Dan Magenheimer
parent
1cfd8bd0f9
commit
5bc20fc597
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@ -447,6 +447,13 @@ HYPERVISOR_hvm_op(int op, void *arg)
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return _hypercall2(unsigned long, hvm_op, op, arg);
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}
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static inline int
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HYPERVISOR_tmem_op(
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struct tmem_op *op)
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{
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return _hypercall1(int, tmem_op, op);
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}
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static inline void
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MULTI_fpu_taskswitch(struct multicall_entry *mcl, int set)
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{
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@ -1,5 +1,6 @@
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obj-y += grant-table.o features.o events.o manage.o balloon.o
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obj-y += xenbus/
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obj-y += tmem.o
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nostackp := $(call cc-option, -fno-stack-protector)
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CFLAGS_features.o := $(nostackp)
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@ -0,0 +1,264 @@
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/*
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* Xen implementation for transcendent memory (tmem)
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*
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* Copyright (C) 2009-2010 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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#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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#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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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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int tmem_enabled;
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static int __init enable_tmem(char *s)
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{
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tmem_enabled = 1;
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return 1;
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}
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__setup("tmem", enable_tmem);
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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 int use_cleancache = 1;
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static int __init no_cleancache(char *s)
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{
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use_cleancache = 0;
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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 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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.flush_page = tmem_cleancache_flush_page,
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.flush_inode = tmem_cleancache_flush_inode,
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.flush_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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static int __init xen_tmem_init(void)
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{
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struct cleancache_ops old_ops;
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if (!xen_domain())
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return 0;
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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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old_ops = 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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@ -58,6 +58,7 @@
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#define __HYPERVISOR_event_channel_op 32
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#define __HYPERVISOR_physdev_op 33
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#define __HYPERVISOR_hvm_op 34
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#define __HYPERVISOR_tmem_op 38
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/* Architecture-specific hypercall definitions. */
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#define __HYPERVISOR_arch_0 48
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@ -461,6 +462,27 @@ typedef uint8_t xen_domain_handle_t[16];
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#define __mk_unsigned_long(x) x ## UL
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#define mk_unsigned_long(x) __mk_unsigned_long(x)
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#define TMEM_SPEC_VERSION 1
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struct tmem_op {
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uint32_t cmd;
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int32_t pool_id;
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union {
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struct { /* for cmd == TMEM_NEW_POOL */
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uint64_t uuid[2];
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uint32_t flags;
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} new;
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struct {
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uint64_t oid[3];
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uint32_t index;
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uint32_t tmem_offset;
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uint32_t pfn_offset;
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uint32_t len;
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GUEST_HANDLE(void) gmfn; /* guest machine page frame */
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} gen;
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} u;
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};
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#else /* __ASSEMBLY__ */
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/* In assembly code we cannot use C numeric constant suffixes. */
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