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shm: Ref counting for unmanaged regions in a dedicated segment

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This commit is contained in:
Alexey Rybalchenko
2023-09-19 10:21:00 +02:00
parent cacf69d5f6
commit 1a0ab3a4e2
7 changed files with 159 additions and 85 deletions
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67
fairmq/shmem/Message.h
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@@ -262,52 +262,50 @@ class Message final : public fair::mq::Message
if (fMeta.fManaged) { // managed segment
fManager.GetSegment(fMeta.fSegmentId);
return ShmHeader::RefCount(fManager.GetAddressFromHandle(fMeta.fHandle, fMeta.fSegmentId));
} else { // unmanaged region
if (fMeta.fShared < 0) { // UR msg is not yet shared
return 1;
} else {
fManager.GetSegment(fMeta.fSegmentId);
return ShmHeader::RefCount(fManager.GetAddressFromHandle(fMeta.fShared, fMeta.fSegmentId));
}
}
if (fMeta.fShared < 0) { // UR msg is not yet shared
return 1;
}
fRegionPtr = fManager.GetRegionFromCache(fMeta.fRegionId);
if (!fRegionPtr) {
throw TransportError(tools::ToString("Cannot get unmanaged region with id ", fMeta.fRegionId));
}
return fRegionPtr->GetRefCountAddressFromHandle(fMeta.fShared)->Get();
}
void Copy(const fair::mq::Message& other) override
{
const Message& otherMsg = static_cast<const Message&>(other);
// if the other message is not initialized, close this one too and return
if (otherMsg.fMeta.fHandle < 0) {
// if the other message is not initialized, close this one too and return
CloseMessage();
return;
}
// if this msg is already initialized, close it first
if (fMeta.fHandle >= 0) {
// if this msg is already initialized, close it first
CloseMessage();
}
if (otherMsg.fMeta.fManaged) { // managed segment
fMeta = otherMsg.fMeta;
fManager.GetSegment(fMeta.fSegmentId);
ShmHeader::IncrementRefCount(fManager.GetAddressFromHandle(fMeta.fHandle, fMeta.fSegmentId));
} else { // unmanaged region
if (otherMsg.fMeta.fShared < 0) { // if UR msg is not yet shared
// TODO: minimize the size to 0 and don't create extra space for user buffer alignment
char* ptr = fManager.Allocate(2, 0);
// point the fShared in the unmanaged region message to the refCount holder
otherMsg.fMeta.fShared = fManager.GetHandleFromAddress(ptr, fMeta.fSegmentId);
// the message needs to be able to locate in which segment the refCount is stored
otherMsg.fMeta.fSegmentId = fMeta.fSegmentId;
// point this message to the same content as the unmanaged region message
fMeta = otherMsg.fMeta;
// increment the refCount
ShmHeader::IncrementRefCount(ptr);
} else { // if the UR msg is already shared
fMeta = otherMsg.fMeta;
fManager.GetSegment(fMeta.fSegmentId);
ShmHeader::IncrementRefCount(fManager.GetAddressFromHandle(fMeta.fShared, fMeta.fSegmentId));
// increment ref count
if (otherMsg.fMeta.fManaged) { // msg in managed segment
fManager.GetSegment(otherMsg.fMeta.fSegmentId);
ShmHeader::IncrementRefCount(fManager.GetAddressFromHandle(otherMsg.fMeta.fHandle, otherMsg.fMeta.fSegmentId));
} else { // msg in unmanaged region
fRegionPtr = fManager.GetRegionFromCache(otherMsg.fMeta.fRegionId);
if (!fRegionPtr) {
throw TransportError(tools::ToString("Cannot get unmanaged region with id ", otherMsg.fMeta.fRegionId));
}
if (otherMsg.fMeta.fShared < 0) {
// UR msg not yet shared, create the reference counting object with count 2
otherMsg.fMeta.fShared = fRegionPtr->HandleFromAddress(&(fRegionPtr->MakeRefCount(2)));
} else {
fRegionPtr->GetRefCountAddressFromHandle(otherMsg.fMeta.fShared)->Increment();
}
}
// copy meta data
fMeta = otherMsg.fMeta;
}
~Message() override { CloseMessage(); }
@@ -344,12 +342,13 @@ class Message final : public fair::mq::Message
}
} else { // unmanaged region
if (fMeta.fShared >= 0) {
// make sure segment is initialized in this transport
fManager.GetSegment(fMeta.fSegmentId);
// release unmanaged region block if ref count is one
uint16_t refCount = ShmHeader::DecrementRefCount(fManager.GetAddressFromHandle(fMeta.fShared, fMeta.fSegmentId));
fRegionPtr = fManager.GetRegionFromCache(fMeta.fRegionId);
if (!fRegionPtr) {
throw TransportError(tools::ToString("Cannot get unmanaged region with id ", fMeta.fRegionId));
}
uint16_t refCount = fRegionPtr->GetRefCountAddressFromHandle(fMeta.fShared)->Decrement();
if (refCount == 1) {
fManager.Deallocate(fMeta.fShared, fMeta.fSegmentId);
fRegionPtr->RemoveRefCount(*(fRegionPtr->GetRefCountAddressFromHandle(fMeta.fShared)));
ReleaseUnmanagedRegionBlock();
}
} else {