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Refactor shared memory storage to allow for multiple named datasets

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This commit is contained in:
Patrick Niklaus
2018-03-28 12:11:47 +00:00
committed by Patrick Niklaus
parent bc120776f0
commit 666ce46d36
8 changed files with 169 additions and 98 deletions
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src/storage/storage.cpp
+41 -29
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@@ -61,7 +61,7 @@ inline void readBlocks(const boost::filesystem::path &path, DataLayout &layout)
}
}
using Monitor = SharedMonitor<SharedDataTimestamp>;
using Monitor = SharedMonitor<SharedRegionRegister>;
Storage::Storage(StorageConfig config_) : config(std::move(config_)) {}
@@ -100,25 +100,24 @@ int Storage::Run(int max_wait)
// Get the next region ID and time stamp without locking shared barriers.
// Because of datastore_lock the only write operation can occur sequentially later.
Monitor monitor(SharedDataTimestamp{REGION_NONE, 0});
auto in_use_region = monitor.data().region;
auto next_timestamp = monitor.data().timestamp + 1;
auto next_region =
in_use_region == REGION_2 || in_use_region == REGION_NONE ? REGION_1 : REGION_2;
Monitor monitor(SharedRegionRegister{});
auto &shared_register = monitor.data();
// This is safe because we have an exclusive lock for all osrm-datastore processes.
auto shm_key = shared_register.ReserveKey();
// ensure that the shared memory region we want to write to is really removed
// this is only needef for failure recovery because we actually wait for all clients
// to detach at the end of the function
if (storage::SharedMemory::RegionExists(next_region))
if (storage::SharedMemory::RegionExists(shm_key))
{
util::Log(logWARNING) << "Old shared memory region " << regionToString(next_region)
<< " still exists.";
util::Log(logWARNING) << "Old shared memory region " << shm_key << " still exists.";
util::UnbufferedLog() << "Retrying removal... ";
storage::SharedMemory::Remove(next_region);
storage::SharedMemory::Remove(shm_key);
util::UnbufferedLog() << "ok.";
}
util::Log() << "Loading data into " << regionToString(next_region);
util::Log() << "Loading data into " << shm_key;
// Populate a memory layout into stack memory
DataLayout layout;
@@ -132,13 +131,16 @@ int Storage::Run(int max_wait)
auto regions_size = encoded_layout.size() + layout.GetSizeOfLayout();
util::Log() << "Data layout has a size of " << encoded_layout.size() << " bytes";
util::Log() << "Allocating shared memory of " << regions_size << " bytes";
auto data_memory = makeSharedMemory(next_region, regions_size);
auto data_memory = makeSharedMemory(shm_key, regions_size);
// Copy memory layout to shared memory and populate data
char *shared_memory_ptr = static_cast<char *>(data_memory->Ptr());
std::copy_n(encoded_layout.data(), encoded_layout.size(), shared_memory_ptr);
PopulateData(layout, shared_memory_ptr + encoded_layout.size());
std::uint32_t next_timestamp = 0;
std::uint8_t in_use_key = SharedRegionRegister::MAX_SHM_KEYS;
{ // Lock for write access shared region mutex
boost::interprocess::scoped_lock<Monitor::mutex_type> lock(monitor.get_mutex(),
boost::interprocess::defer_lock);
@@ -148,13 +150,10 @@ int Storage::Run(int max_wait)
if (!lock.timed_lock(boost::posix_time::microsec_clock::universal_time() +
boost::posix_time::seconds(max_wait)))
{
util::Log(logWARNING)
<< "Could not aquire current region lock after " << max_wait
<< " seconds. Removing locked block and creating a new one. All currently "
"attached processes will not receive notifications and must be restarted";
Monitor::remove();
in_use_region = REGION_NONE;
monitor = Monitor(SharedDataTimestamp{REGION_NONE, 0});
util::Log(logERROR) << "Could not aquire current region lock after " << max_wait
<< " seconds. Data update failed.";
SharedMemory::Remove(shm_key);
return EXIT_FAILURE;
}
}
else
@@ -162,32 +161,45 @@ int Storage::Run(int max_wait)
lock.lock();
}
// Update the current region ID and timestamp
monitor.data().region = next_region;
monitor.data().timestamp = next_timestamp;
auto region_id = shared_register.Find("data");
if (region_id == SharedRegionRegister::INVALID_REGION_ID)
{
region_id = shared_register.Register("data", shm_key);
}
else
{
auto& shared_region = shared_register.GetRegion(region_id);
next_timestamp = shared_region.timestamp + 1;
in_use_key = shared_region.shm_key;
shared_region.shm_key = shm_key;
shared_region.timestamp = next_timestamp;
}
}
util::Log() << "All data loaded. Notify all client about new data in "
<< regionToString(next_region) << " with timestamp " << next_timestamp;
util::Log() << "All data loaded. Notify all client about new data in " << shm_key
<< " with timestamp " << next_timestamp;
monitor.notify_all();
// SHMCTL(2): Mark the segment to be destroyed. The segment will actually be destroyed
// only after the last process detaches it.
if (in_use_region != REGION_NONE && storage::SharedMemory::RegionExists(in_use_region))
if (in_use_key != SharedRegionRegister::MAX_SHM_KEYS &&
storage::SharedMemory::RegionExists(in_use_key))
{
util::UnbufferedLog() << "Marking old shared memory region "
<< regionToString(in_use_region) << " for removal... ";
util::UnbufferedLog() << "Marking old shared memory region " << in_use_key
<< " for removal... ";
// aquire a handle for the old shared memory region before we mark it for deletion
// we will need this to wait for all users to detach
auto in_use_shared_memory = makeSharedMemory(in_use_region);
auto in_use_shared_memory = makeSharedMemory(in_use_key);
storage::SharedMemory::Remove(in_use_region);
storage::SharedMemory::Remove(in_use_key);
util::UnbufferedLog() << "ok.";
util::UnbufferedLog() << "Waiting for clients to detach... ";
in_use_shared_memory->WaitForDetach();
util::UnbufferedLog() << " ok.";
shared_register.ReleaseKey(in_use_key);
}
util::Log() << "All clients switched.";