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author | Mathias Agopian <mathias@google.com> | 2010-05-07 15:58:44 -0700 |
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committer | Mathias Agopian <mathias@google.com> | 2010-05-12 17:28:20 -0700 |
commit | 59751dbf7d8f12aeb5c4c07719b7dbbf1f9b5d4b (patch) | |
tree | a1f1d7119a8109d06cfc2f24b26284ff7627de7a /libs/surfaceflinger_client/SharedBufferStack.cpp | |
parent | 9f2c4fd9a14ea79e4cbbd3ab8925794711a6411c (diff) | |
download | frameworks_base-59751dbf7d8f12aeb5c4c07719b7dbbf1f9b5d4b.zip frameworks_base-59751dbf7d8f12aeb5c4c07719b7dbbf1f9b5d4b.tar.gz frameworks_base-59751dbf7d8f12aeb5c4c07719b7dbbf1f9b5d4b.tar.bz2 |
SharedBufferStack now can grow up to 16 buffers.
there is a new resize() api, which currently only allows growing.
Change-Id: Ia37b81b73be466d2491ffed7f3a23cd8e113c6fe
Diffstat (limited to 'libs/surfaceflinger_client/SharedBufferStack.cpp')
-rw-r--r-- | libs/surfaceflinger_client/SharedBufferStack.cpp | 91 |
1 files changed, 85 insertions, 6 deletions
diff --git a/libs/surfaceflinger_client/SharedBufferStack.cpp b/libs/surfaceflinger_client/SharedBufferStack.cpp index d6b2375..4a98026 100644 --- a/libs/surfaceflinger_client/SharedBufferStack.cpp +++ b/libs/surfaceflinger_client/SharedBufferStack.cpp @@ -305,7 +305,6 @@ SharedBufferServer::RetireUpdate::RetireUpdate( : UpdateBase(sbb), numBuffers(numBuffers) { } ssize_t SharedBufferServer::RetireUpdate::operator()() { - // head is only written in this function, which is single-thread. int32_t head = stack.head; if (uint32_t(head) >= NUM_BUFFER_MAX) return BAD_VALUE; @@ -322,16 +321,14 @@ ssize_t SharedBufferServer::RetireUpdate::operator()() { } } while (android_atomic_cmpxchg(queued, queued-1, &stack.queued)); - // update the head pointer - head = ((head+1 >= numBuffers) ? 0 : head+1); - // lock the buffer before advancing head, which automatically unlocks // the buffer we preventively locked upon entering this function + head = (head + 1) % numBuffers; android_atomic_write(stack.index[head], &stack.inUse); - // advance head + // head is only modified here, so we don't need to use cmpxchg android_atomic_write(head, &stack.head); - + // now that head has moved, we can increment the number of available buffers android_atomic_inc(&stack.available); return head; @@ -450,6 +447,14 @@ status_t SharedBufferClient::setDirtyRegion(int buf, const Region& reg) return stack.setDirtyRegion(buf, reg); } +status_t SharedBufferClient::setBufferCount(int bufferCount) +{ + if (uint32_t(bufferCount) >= NUM_BUFFER_MAX) + return BAD_VALUE; + mNumBuffers = bufferCount; + return NO_ERROR; +} + // ---------------------------------------------------------------------------- SharedBufferServer::SharedBufferServer(SharedClient* sharedClient, @@ -463,6 +468,7 @@ SharedBufferServer::SharedBufferServer(SharedClient* sharedClient, mSharedStack->reallocMask = 0; memset(mSharedStack->buffers, 0, sizeof(mSharedStack->buffers)); for (int i=0 ; i<num ; i++) { + mBufferList.add(i); mSharedStack->index[i] = i; } } @@ -525,12 +531,85 @@ Region SharedBufferServer::getDirtyRegion(int buf) const return stack.getDirtyRegion(buf); } + +/* + * + * NOTE: this is not thread-safe on the server-side, meaning + * 'head' cannot move during this operation. The client-side + * can safely operate an usual. + * + */ +status_t SharedBufferServer::resize(int newNumBuffers) +{ + if (uint32_t(newNumBuffers) >= NUM_BUFFER_MAX) + return BAD_VALUE; + + // for now we're not supporting shrinking + const int numBuffers = mNumBuffers; + if (newNumBuffers < numBuffers) + return BAD_VALUE; + + SharedBufferStack& stack( *mSharedStack ); + const int extra = newNumBuffers - numBuffers; + + // read the head, make sure it's valid + int32_t head = stack.head; + if (uint32_t(head) >= NUM_BUFFER_MAX) + return BAD_VALUE; + + int base = numBuffers; + int32_t avail = stack.available; + int tail = head - avail + 1; + if (tail >= 0) { + int8_t* const index = const_cast<int8_t*>(stack.index); + const int nb = numBuffers - head; + memmove(&index[head + extra], &index[head], nb); + base = head; + // move head 'extra' ahead, this doesn't impact stack.index[head]; + stack.head = head + extra; + } + stack.available += extra; + + // fill the new free space with unused buffers + BufferList::const_iterator curr(mBufferList.free_begin()); + for (int i=0 ; i<extra ; i++) { + stack.index[base+i] = *curr++; + mBufferList.add(stack.index[base+i]); + } + + mNumBuffers = newNumBuffers; + return NO_ERROR; +} + SharedBufferStack::Statistics SharedBufferServer::getStats() const { SharedBufferStack& stack( *mSharedStack ); return stack.stats; } +// --------------------------------------------------------------------------- +status_t SharedBufferServer::BufferList::add(int value) +{ + if (uint32_t(value) >= mCapacity) + return BAD_VALUE; + uint32_t mask = 1<<(31-value); + if (mList & mask) + return ALREADY_EXISTS; + mList |= mask; + return NO_ERROR; +} + +status_t SharedBufferServer::BufferList::remove(int value) +{ + if (uint32_t(value) >= mCapacity) + return BAD_VALUE; + uint32_t mask = 1<<(31-value); + if (!(mList & mask)) + return NAME_NOT_FOUND; + mList &= ~mask; + return NO_ERROR; +} + // --------------------------------------------------------------------------- }; // namespace android |