1/*
2 * Copyright (c) 2012-2013, 2015-2016, 2018 ARM Limited
3 * All rights reserved.
4 *
5 * The license below extends only to copyright in the software and shall
6 * not be construed as granting a license to any other intellectual
7 * property including but not limited to intellectual property relating
8 * to a hardware implementation of the functionality of the software
9 * licensed hereunder. You may use the software subject to the license
10 * terms below provided that you ensure that this notice is replicated
11 * unmodified and in its entirety in all distributions of the software,
12 * modified or unmodified, in source code or in binary form.
13 *
14 * Copyright (c) 2002-2005 The Regents of The University of Michigan
15 * All rights reserved.
16 *
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions are
19 * met: redistributions of source code must retain the above copyright
20 * notice, this list of conditions and the following disclaimer;
21 * redistributions in binary form must reproduce the above copyright
22 * notice, this list of conditions and the following disclaimer in the
23 * documentation and/or other materials provided with the distribution;
24 * neither the name of the copyright holders nor the names of its
25 * contributors may be used to endorse or promote products derived from
26 * this software without specific prior written permission.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
31 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
32 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
33 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
34 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
38 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
39 *
40 * Authors: Erik Hallnor
41 */
42
43/**
44 * @file
45 * Miss Status and Handling Register (MSHR) declaration.
46 */
47
48#ifndef __MEM_CACHE_MSHR_HH__
49#define __MEM_CACHE_MSHR_HH__
50
51#include <list>
52
53#include "base/printable.hh"
54#include "mem/cache/queue_entry.hh"
55
| 1/*
2 * Copyright (c) 2012-2013, 2015-2016, 2018 ARM Limited
3 * All rights reserved.
4 *
5 * The license below extends only to copyright in the software and shall
6 * not be construed as granting a license to any other intellectual
7 * property including but not limited to intellectual property relating
8 * to a hardware implementation of the functionality of the software
9 * licensed hereunder. You may use the software subject to the license
10 * terms below provided that you ensure that this notice is replicated
11 * unmodified and in its entirety in all distributions of the software,
12 * modified or unmodified, in source code or in binary form.
13 *
14 * Copyright (c) 2002-2005 The Regents of The University of Michigan
15 * All rights reserved.
16 *
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions are
19 * met: redistributions of source code must retain the above copyright
20 * notice, this list of conditions and the following disclaimer;
21 * redistributions in binary form must reproduce the above copyright
22 * notice, this list of conditions and the following disclaimer in the
23 * documentation and/or other materials provided with the distribution;
24 * neither the name of the copyright holders nor the names of its
25 * contributors may be used to endorse or promote products derived from
26 * this software without specific prior written permission.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
31 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
32 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
33 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
34 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
38 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
39 *
40 * Authors: Erik Hallnor
41 */
42
43/**
44 * @file
45 * Miss Status and Handling Register (MSHR) declaration.
46 */
47
48#ifndef __MEM_CACHE_MSHR_HH__
49#define __MEM_CACHE_MSHR_HH__
50
51#include <list>
52
53#include "base/printable.hh"
54#include "mem/cache/queue_entry.hh"
55
|
56class Cache;
| 56class BaseCache;
|
57
58/**
59 * Miss Status and handling Register. This class keeps all the information
60 * needed to handle a cache miss including a list of target requests.
61 * @sa \ref gem5MemorySystem "gem5 Memory System"
62 */
63class MSHR : public QueueEntry, public Printable
64{
65
66 /**
67 * Consider the queues friends to avoid making everything public.
68 */
69 template<typename Entry>
70 friend class Queue;
71 friend class MSHRQueue;
72
73 private:
74
75 /** Flag set by downstream caches */
76 bool downstreamPending;
77
78 /**
79 * Here we use one flag to track both if:
80 *
81 * 1. We are going to become owner or not, i.e., we will get the
82 * block in an ownership state (Owned or Modified) with BlkDirty
83 * set. This determines whether or not we are going to become the
84 * responder and ordering point for future requests that we snoop.
85 *
86 * 2. We know that we are going to get a writable block, i.e. we
87 * will get the block in writable state (Exclusive or Modified
88 * state) with BlkWritable set. That determines whether additional
89 * targets with needsWritable set will be able to be satisfied, or
90 * if not should be put on the deferred list to possibly wait for
91 * another request that does give us writable access.
92 *
93 * Condition 2 is actually just a shortcut that saves us from
94 * possibly building a deferred target list and calling
95 * promoteWritable() every time we get a writable block. Condition
96 * 1, tracking ownership, is what is important. However, we never
97 * receive ownership without marking the block dirty, and
98 * consequently use pendingModified to track both ownership and
99 * writability rather than having separate pendingDirty and
100 * pendingWritable flags.
101 */
102 bool pendingModified;
103
104 /** Did we snoop an invalidate while waiting for data? */
105 bool postInvalidate;
106
107 /** Did we snoop a read while waiting for data? */
108 bool postDowngrade;
109
110 public:
111
112 /** True if the entry is just a simple forward from an upper level */
113 bool isForward;
114
115 class Target {
116 public:
117
118 enum Source {
119 FromCPU,
120 FromSnoop,
121 FromPrefetcher
122 };
123
124 const Tick recvTime; //!< Time when request was received (for stats)
125 const Tick readyTime; //!< Time when request is ready to be serviced
126 const Counter order; //!< Global order (for memory consistency mgmt)
127 const PacketPtr pkt; //!< Pending request packet.
128 const Source source; //!< Request from cpu, memory, or prefetcher?
129
130 /**
131 * We use this flag to track whether we have cleared the
132 * downstreamPending flag for the MSHR of the cache above
133 * where this packet originates from and guard noninitial
134 * attempts to clear it.
135 *
136 * The flag markedPending needs to be updated when the
137 * TargetList is in service which can be:
138 * 1) during the Target instantiation if the MSHR is in
139 * service and the target is not deferred,
140 * 2) when the MSHR becomes in service if the target is not
141 * deferred,
142 * 3) or when the TargetList is promoted (deferredTargets ->
143 * targets).
144 */
145 bool markedPending;
146
147 const bool allocOnFill; //!< Should the response servicing this
148 //!< target list allocate in the cache?
149
150 Target(PacketPtr _pkt, Tick _readyTime, Counter _order,
151 Source _source, bool _markedPending, bool alloc_on_fill)
152 : recvTime(curTick()), readyTime(_readyTime), order(_order),
153 pkt(_pkt), source(_source), markedPending(_markedPending),
154 allocOnFill(alloc_on_fill)
155 {}
156 };
157
158 class TargetList : public std::list<Target> {
159
160 public:
161 bool needsWritable;
162 bool hasUpgrade;
163 /** Set when the response should allocate on fill */
164 bool allocOnFill;
165 /**
166 * Determine whether there was at least one non-snooping
167 * target coming from another cache.
168 */
169 bool hasFromCache;
170
171 TargetList();
172
173 /**
174 * Use the provided packet and the source to update the
175 * flags of this TargetList.
176 *
177 * @param pkt Packet considered for the flag update
178 * @param source Indicates the source of the packet
179 * @param alloc_on_fill Whether the pkt would allocate on a fill
180 */
181 void updateFlags(PacketPtr pkt, Target::Source source,
182 bool alloc_on_fill);
183
184 void resetFlags() {
185 needsWritable = false;
186 hasUpgrade = false;
187 allocOnFill = false;
188 hasFromCache = false;
189 }
190
191 /**
192 * Goes through the list of targets and uses them to populate
193 * the flags of this TargetList. When the function returns the
194 * flags are consistent with the properties of packets in the
195 * list.
196 */
197 void populateFlags();
198
199 /**
200 * Tests if the flags of this TargetList have their default
201 * values.
202 */
203 bool isReset() const {
204 return !needsWritable && !hasUpgrade && !allocOnFill &&
205 !hasFromCache;
206 }
207
208 /**
209 * Add the specified packet in the TargetList. This function
210 * stores information related to the added packet and updates
211 * accordingly the flags.
212 *
213 * @param pkt Packet considered for adding
214 * @param readTime Tick at which the packet is processed by this cache
215 * @param order A counter giving a unique id to each target
216 * @param source Indicates the source agent of the packet
217 * @param markPending Set for deferred targets or pending MSHRs
218 * @param alloc_on_fill Whether it should allocate on a fill
219 */
220 void add(PacketPtr pkt, Tick readyTime, Counter order,
221 Target::Source source, bool markPending,
222 bool alloc_on_fill);
223
224 /**
225 * Convert upgrades to the equivalent request if the cache line they
226 * refer to would have been invalid (Upgrade -> ReadEx, SC* -> Fail).
227 * Used to rejig ordering between targets waiting on an MSHR. */
228 void replaceUpgrades();
229
230 void clearDownstreamPending();
231 bool checkFunctional(PacketPtr pkt);
232 void print(std::ostream &os, int verbosity,
233 const std::string &prefix) const;
234 };
235
236 /** A list of MSHRs. */
237 typedef std::list<MSHR *> List;
238 /** MSHR list iterator. */
239 typedef List::iterator Iterator;
240
241 /** The pending* and post* flags are only valid if inService is
242 * true. Using the accessor functions lets us detect if these
243 * flags are accessed improperly.
244 */
245
246 /** True if we need to get a writable copy of the block. */
247 bool needsWritable() const { return targets.needsWritable; }
248
249 bool isCleaning() const {
250 PacketPtr pkt = targets.front().pkt;
251 return pkt->isClean();
252 }
253
254 bool isPendingModified() const {
255 assert(inService); return pendingModified;
256 }
257
258 bool hasPostInvalidate() const {
259 assert(inService); return postInvalidate;
260 }
261
262 bool hasPostDowngrade() const {
263 assert(inService); return postDowngrade;
264 }
265
| 57
58/**
59 * Miss Status and handling Register. This class keeps all the information
60 * needed to handle a cache miss including a list of target requests.
61 * @sa \ref gem5MemorySystem "gem5 Memory System"
62 */
63class MSHR : public QueueEntry, public Printable
64{
65
66 /**
67 * Consider the queues friends to avoid making everything public.
68 */
69 template<typename Entry>
70 friend class Queue;
71 friend class MSHRQueue;
72
73 private:
74
75 /** Flag set by downstream caches */
76 bool downstreamPending;
77
78 /**
79 * Here we use one flag to track both if:
80 *
81 * 1. We are going to become owner or not, i.e., we will get the
82 * block in an ownership state (Owned or Modified) with BlkDirty
83 * set. This determines whether or not we are going to become the
84 * responder and ordering point for future requests that we snoop.
85 *
86 * 2. We know that we are going to get a writable block, i.e. we
87 * will get the block in writable state (Exclusive or Modified
88 * state) with BlkWritable set. That determines whether additional
89 * targets with needsWritable set will be able to be satisfied, or
90 * if not should be put on the deferred list to possibly wait for
91 * another request that does give us writable access.
92 *
93 * Condition 2 is actually just a shortcut that saves us from
94 * possibly building a deferred target list and calling
95 * promoteWritable() every time we get a writable block. Condition
96 * 1, tracking ownership, is what is important. However, we never
97 * receive ownership without marking the block dirty, and
98 * consequently use pendingModified to track both ownership and
99 * writability rather than having separate pendingDirty and
100 * pendingWritable flags.
101 */
102 bool pendingModified;
103
104 /** Did we snoop an invalidate while waiting for data? */
105 bool postInvalidate;
106
107 /** Did we snoop a read while waiting for data? */
108 bool postDowngrade;
109
110 public:
111
112 /** True if the entry is just a simple forward from an upper level */
113 bool isForward;
114
115 class Target {
116 public:
117
118 enum Source {
119 FromCPU,
120 FromSnoop,
121 FromPrefetcher
122 };
123
124 const Tick recvTime; //!< Time when request was received (for stats)
125 const Tick readyTime; //!< Time when request is ready to be serviced
126 const Counter order; //!< Global order (for memory consistency mgmt)
127 const PacketPtr pkt; //!< Pending request packet.
128 const Source source; //!< Request from cpu, memory, or prefetcher?
129
130 /**
131 * We use this flag to track whether we have cleared the
132 * downstreamPending flag for the MSHR of the cache above
133 * where this packet originates from and guard noninitial
134 * attempts to clear it.
135 *
136 * The flag markedPending needs to be updated when the
137 * TargetList is in service which can be:
138 * 1) during the Target instantiation if the MSHR is in
139 * service and the target is not deferred,
140 * 2) when the MSHR becomes in service if the target is not
141 * deferred,
142 * 3) or when the TargetList is promoted (deferredTargets ->
143 * targets).
144 */
145 bool markedPending;
146
147 const bool allocOnFill; //!< Should the response servicing this
148 //!< target list allocate in the cache?
149
150 Target(PacketPtr _pkt, Tick _readyTime, Counter _order,
151 Source _source, bool _markedPending, bool alloc_on_fill)
152 : recvTime(curTick()), readyTime(_readyTime), order(_order),
153 pkt(_pkt), source(_source), markedPending(_markedPending),
154 allocOnFill(alloc_on_fill)
155 {}
156 };
157
158 class TargetList : public std::list<Target> {
159
160 public:
161 bool needsWritable;
162 bool hasUpgrade;
163 /** Set when the response should allocate on fill */
164 bool allocOnFill;
165 /**
166 * Determine whether there was at least one non-snooping
167 * target coming from another cache.
168 */
169 bool hasFromCache;
170
171 TargetList();
172
173 /**
174 * Use the provided packet and the source to update the
175 * flags of this TargetList.
176 *
177 * @param pkt Packet considered for the flag update
178 * @param source Indicates the source of the packet
179 * @param alloc_on_fill Whether the pkt would allocate on a fill
180 */
181 void updateFlags(PacketPtr pkt, Target::Source source,
182 bool alloc_on_fill);
183
184 void resetFlags() {
185 needsWritable = false;
186 hasUpgrade = false;
187 allocOnFill = false;
188 hasFromCache = false;
189 }
190
191 /**
192 * Goes through the list of targets and uses them to populate
193 * the flags of this TargetList. When the function returns the
194 * flags are consistent with the properties of packets in the
195 * list.
196 */
197 void populateFlags();
198
199 /**
200 * Tests if the flags of this TargetList have their default
201 * values.
202 */
203 bool isReset() const {
204 return !needsWritable && !hasUpgrade && !allocOnFill &&
205 !hasFromCache;
206 }
207
208 /**
209 * Add the specified packet in the TargetList. This function
210 * stores information related to the added packet and updates
211 * accordingly the flags.
212 *
213 * @param pkt Packet considered for adding
214 * @param readTime Tick at which the packet is processed by this cache
215 * @param order A counter giving a unique id to each target
216 * @param source Indicates the source agent of the packet
217 * @param markPending Set for deferred targets or pending MSHRs
218 * @param alloc_on_fill Whether it should allocate on a fill
219 */
220 void add(PacketPtr pkt, Tick readyTime, Counter order,
221 Target::Source source, bool markPending,
222 bool alloc_on_fill);
223
224 /**
225 * Convert upgrades to the equivalent request if the cache line they
226 * refer to would have been invalid (Upgrade -> ReadEx, SC* -> Fail).
227 * Used to rejig ordering between targets waiting on an MSHR. */
228 void replaceUpgrades();
229
230 void clearDownstreamPending();
231 bool checkFunctional(PacketPtr pkt);
232 void print(std::ostream &os, int verbosity,
233 const std::string &prefix) const;
234 };
235
236 /** A list of MSHRs. */
237 typedef std::list<MSHR *> List;
238 /** MSHR list iterator. */
239 typedef List::iterator Iterator;
240
241 /** The pending* and post* flags are only valid if inService is
242 * true. Using the accessor functions lets us detect if these
243 * flags are accessed improperly.
244 */
245
246 /** True if we need to get a writable copy of the block. */
247 bool needsWritable() const { return targets.needsWritable; }
248
249 bool isCleaning() const {
250 PacketPtr pkt = targets.front().pkt;
251 return pkt->isClean();
252 }
253
254 bool isPendingModified() const {
255 assert(inService); return pendingModified;
256 }
257
258 bool hasPostInvalidate() const {
259 assert(inService); return postInvalidate;
260 }
261
262 bool hasPostDowngrade() const {
263 assert(inService); return postDowngrade;
264 }
265
|
266 bool sendPacket(Cache &cache);
| 266 bool sendPacket(BaseCache &cache);
|
267
268 bool allocOnFill() const {
269 return targets.allocOnFill;
270 }
271
272 /**
273 * Determine if there are non-deferred requests from other caches
274 *
275 * @return true if any of the targets is from another cache
276 */
277 bool hasFromCache() const {
278 return targets.hasFromCache;
279 }
280
281 private:
282
283 /**
284 * Pointer to this MSHR on the ready list.
285 * @sa MissQueue, MSHRQueue::readyList
286 */
287 Iterator readyIter;
288
289 /**
290 * Pointer to this MSHR on the allocated list.
291 * @sa MissQueue, MSHRQueue::allocatedList
292 */
293 Iterator allocIter;
294
295 /** List of all requests that match the address */
296 TargetList targets;
297
298 TargetList deferredTargets;
299
300 public:
301
302 /**
303 * Allocate a miss to this MSHR.
304 * @param blk_addr The address of the block.
305 * @param blk_size The number of bytes to request.
306 * @param pkt The original miss.
307 * @param when_ready When should the MSHR be ready to act upon.
308 * @param _order The logical order of this MSHR
309 * @param alloc_on_fill Should the cache allocate a block on fill
310 */
311 void allocate(Addr blk_addr, unsigned blk_size, PacketPtr pkt,
312 Tick when_ready, Counter _order, bool alloc_on_fill);
313
314 void markInService(bool pending_modified_resp);
315
316 void clearDownstreamPending();
317
318 /**
319 * Mark this MSHR as free.
320 */
321 void deallocate();
322
323 /**
324 * Add a request to the list of targets.
325 * @param target The target.
326 */
327 void allocateTarget(PacketPtr target, Tick when, Counter order,
328 bool alloc_on_fill);
329 bool handleSnoop(PacketPtr target, Counter order);
330
331 /** A simple constructor. */
332 MSHR();
333
334 /**
335 * Returns the current number of allocated targets.
336 * @return The current number of allocated targets.
337 */
338 int getNumTargets() const
339 { return targets.size() + deferredTargets.size(); }
340
341 /**
342 * Extracts the subset of the targets that can be serviced given a
343 * received response. This function returns the targets list
344 * unless the response is a ReadRespWithInvalidate. The
345 * ReadRespWithInvalidate is only invalidating response that its
346 * invalidation was not expected when the request (a
347 * ReadSharedReq) was sent out. For ReadRespWithInvalidate we can
348 * safely service only the first FromCPU target and all FromSnoop
349 * targets (inform all snoopers that we no longer have the block).
350 *
351 * @param pkt The response from the downstream memory
352 */
353 TargetList extractServiceableTargets(PacketPtr pkt);
354
355 /**
356 * Returns true if there are targets left.
357 * @return true if there are targets
358 */
359 bool hasTargets() const { return !targets.empty(); }
360
361 /**
362 * Returns a reference to the first target.
363 * @return A pointer to the first target.
364 */
365 Target *getTarget()
366 {
367 assert(hasTargets());
368 return &targets.front();
369 }
370
371 /**
372 * Pop first target.
373 */
374 void popTarget()
375 {
376 targets.pop_front();
377 }
378
379 bool promoteDeferredTargets();
380
381 void promoteWritable();
382
383 bool checkFunctional(PacketPtr pkt);
384
385 /**
386 * Prints the contents of this MSHR for debugging.
387 */
388 void print(std::ostream &os,
389 int verbosity = 0,
390 const std::string &prefix = "") const;
391 /**
392 * A no-args wrapper of print(std::ostream...) meant to be
393 * invoked from DPRINTFs avoiding string overheads in fast mode
394 *
395 * @return string with mshr fields + [deferred]targets
396 */
397 std::string print() const;
398};
399
400#endif // __MEM_CACHE_MSHR_HH__
| 267
268 bool allocOnFill() const {
269 return targets.allocOnFill;
270 }
271
272 /**
273 * Determine if there are non-deferred requests from other caches
274 *
275 * @return true if any of the targets is from another cache
276 */
277 bool hasFromCache() const {
278 return targets.hasFromCache;
279 }
280
281 private:
282
283 /**
284 * Pointer to this MSHR on the ready list.
285 * @sa MissQueue, MSHRQueue::readyList
286 */
287 Iterator readyIter;
288
289 /**
290 * Pointer to this MSHR on the allocated list.
291 * @sa MissQueue, MSHRQueue::allocatedList
292 */
293 Iterator allocIter;
294
295 /** List of all requests that match the address */
296 TargetList targets;
297
298 TargetList deferredTargets;
299
300 public:
301
302 /**
303 * Allocate a miss to this MSHR.
304 * @param blk_addr The address of the block.
305 * @param blk_size The number of bytes to request.
306 * @param pkt The original miss.
307 * @param when_ready When should the MSHR be ready to act upon.
308 * @param _order The logical order of this MSHR
309 * @param alloc_on_fill Should the cache allocate a block on fill
310 */
311 void allocate(Addr blk_addr, unsigned blk_size, PacketPtr pkt,
312 Tick when_ready, Counter _order, bool alloc_on_fill);
313
314 void markInService(bool pending_modified_resp);
315
316 void clearDownstreamPending();
317
318 /**
319 * Mark this MSHR as free.
320 */
321 void deallocate();
322
323 /**
324 * Add a request to the list of targets.
325 * @param target The target.
326 */
327 void allocateTarget(PacketPtr target, Tick when, Counter order,
328 bool alloc_on_fill);
329 bool handleSnoop(PacketPtr target, Counter order);
330
331 /** A simple constructor. */
332 MSHR();
333
334 /**
335 * Returns the current number of allocated targets.
336 * @return The current number of allocated targets.
337 */
338 int getNumTargets() const
339 { return targets.size() + deferredTargets.size(); }
340
341 /**
342 * Extracts the subset of the targets that can be serviced given a
343 * received response. This function returns the targets list
344 * unless the response is a ReadRespWithInvalidate. The
345 * ReadRespWithInvalidate is only invalidating response that its
346 * invalidation was not expected when the request (a
347 * ReadSharedReq) was sent out. For ReadRespWithInvalidate we can
348 * safely service only the first FromCPU target and all FromSnoop
349 * targets (inform all snoopers that we no longer have the block).
350 *
351 * @param pkt The response from the downstream memory
352 */
353 TargetList extractServiceableTargets(PacketPtr pkt);
354
355 /**
356 * Returns true if there are targets left.
357 * @return true if there are targets
358 */
359 bool hasTargets() const { return !targets.empty(); }
360
361 /**
362 * Returns a reference to the first target.
363 * @return A pointer to the first target.
364 */
365 Target *getTarget()
366 {
367 assert(hasTargets());
368 return &targets.front();
369 }
370
371 /**
372 * Pop first target.
373 */
374 void popTarget()
375 {
376 targets.pop_front();
377 }
378
379 bool promoteDeferredTargets();
380
381 void promoteWritable();
382
383 bool checkFunctional(PacketPtr pkt);
384
385 /**
386 * Prints the contents of this MSHR for debugging.
387 */
388 void print(std::ostream &os,
389 int verbosity = 0,
390 const std::string &prefix = "") const;
391 /**
392 * A no-args wrapper of print(std::ostream...) meant to be
393 * invoked from DPRINTFs avoiding string overheads in fast mode
394 *
395 * @return string with mshr fields + [deferred]targets
396 */
397 std::string print() const;
398};
399
400#endif // __MEM_CACHE_MSHR_HH__
|