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[Feat] (MG_Remote/Server): ServerLoop - the mgl-srv-apply thread, its affinity mask, the three-way park predicate, the blocking control mailbox, the bounded Stop, and the twelve EGL forwarders

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swung0x48
2026-09-16 05:45:15 -04:00
parent 8dbe230ae3
commit 23c0468775
2 changed files with 856 additions and 18 deletions
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MobileGL/MG_Remote/Server/ServerLoop.cpp
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@@ -6,36 +6,500 @@
// SPDX-License-Identifier: LGPL-3.0-only // SPDX-License-Identifier: LGPL-3.0-only
// End of Source File Header // End of Source File Header
// P5 c0 stubs for package v1 - the phase's highest-risk package. // P5 package v1: the apply thread, its affinity, its parking, and the EGL ownership move.
#include "ServerLoop.h" #include "ServerLoop.h"
#include <Config.h>
#include <MG_Backend/BackendObjects.h>
#include <MG_Util/Debug/Log.h> #include <MG_Util/Debug/Log.h>
#include <chrono>
#include <cstdlib> #include <cstdlib>
#include <cstdio>
#if defined(__linux__) || defined(__ANDROID__)
#include <pthread.h>
#include <sched.h>
#endif
namespace MobileGL::MG_Remote::Server { namespace MobileGL::MG_Remote::Server {
#define MGP5_C0_STUB(what) \ namespace {
do { \
MGLOG_F("MGPipe: Fatal{UnimplementedServerLoop, \"%s\"} - P5 package v1 has not landed " \
"this yet; c0 shipped the signature only", \
what); \
std::abort(); \
} while (0)
MobileGLResult ServerLoop::Start(ServerSession&) { MGP5_C0_STUB("ServerLoop::Start"); } // The bounded join. InProcessTransportTest.cpp:344 uses five seconds for the same
// reason: a lost wakeup must be a RED TEST and not a hung CI job.
constexpr Uint32 kJoinTimeoutMs = 5000;
void ServerLoop::Stop() { MGP5_C0_STUB("ServerLoop::Stop"); } // A core counts as "big" if its cpufreq ceiling is within 15% of the fastest core's -
// the identical rule and the identical constant as ShaderCompilePool.cpp:28 and :73-95.
// The probe is re-derived here rather than exported from there because the two want
// DIFFERENT ANSWERS from the same data: the pool wants a COUNT (how many workers), and
// an affinity wants a MASK (which cpus). DetectBigCoreCount() cannot answer the second,
// so exporting it would have meant either a second function in another package's file
// or a mask reconstructed from a count, which is wrong on any asymmetric topology whose
// big cores are not cpu0..cpuN-1.
constexpr Uint64 kBigCoreFrequencyPercent = 85;
// Not a stub: teardown asks this to decide whether to Kill and join at all, and a teardown Uint64 ReadCpuMaxFrequencyKHz(const Uint cpu) {
// helper that aborts when the thread was never started is a hang in the shutdown path. char path[128];
Bool ServerLoop::Running() const { return m_running; } std::snprintf(path, sizeof(path),
"/sys/devices/system/cpu/cpu%u/cpufreq/cpuinfo_max_freq", cpu);
std::FILE* file = std::fopen(path, "r");
if (file == nullptr) return 0;
unsigned long long value = 0;
const int scanned = std::fscanf(file, "%llu", &value);
std::fclose(file);
return scanned == 1 ? static_cast<Uint64>(value) : 0;
}
MG_Backend::BackendObject* ServerLoop::Backend() { MGP5_C0_STUB("ServerLoop::Backend"); } // The set of cpus whose ceiling is within 15% of the peak, as a bit per cpu. Zero when
// the topology cannot be read - Windows, macOS, a container that hides the cpufreq
// tree, or a partially readable one - because with no asymmetry information the honest
// answer is "do not pin", not "pin to a guess".
Uint64 DetectBigCoreMask() {
const Uint cpuCount = std::min(64u, std::max(1u, std::thread::hardware_concurrency()));
Uint64 frequencies[64] = {};
for (Uint cpu = 0; cpu < cpuCount; ++cpu) {
frequencies[cpu] = ReadCpuMaxFrequencyKHz(cpu);
if (frequencies[cpu] == 0) return 0;
}
Uint64 peak = 0;
for (Uint cpu = 0; cpu < cpuCount; ++cpu) peak = std::max(peak, frequencies[cpu]);
if (peak == 0) return 0;
const Uint64 threshold = peak * kBigCoreFrequencyPercent / 100;
Uint64 mask = 0;
for (Uint cpu = 0; cpu < cpuCount; ++cpu) {
if (frequencies[cpu] >= threshold) mask |= (1ull << cpu);
}
return mask;
}
MobileGLResult ServerLoop::RunOnApplyThread(ControlWork, void*) { // MOBILEGL_IPC_SERVER_AFFINITY = `auto` | `off` | an explicit mask (0x... or decimal).
MGP5_C0_STUB("ServerLoop::RunOnApplyThread"); // The RAW STRING is what Config keeps, because the resolved mask is what gets logged -
// "an affinity that silently did nothing looks exactly like one that worked"
// (CONTRACT-P5 5).
Uint64 RequestedAffinityMask(const char* raw, Bool* outRecognised) {
*outRecognised = true;
if (raw == nullptr || raw[0] == '\0') return DetectBigCoreMask();
if (std::strcmp(raw, "auto") == 0) return DetectBigCoreMask();
if (std::strcmp(raw, "off") == 0) return 0;
char* end = nullptr;
const unsigned long long parsed = std::strtoull(raw, &end, 0);
if (end == raw || (end != nullptr && *end != '\0')) {
*outRecognised = false;
return 0;
}
return static_cast<Uint64>(parsed);
}
void NameThisThread(const char* name) {
#if defined(__linux__) || defined(__ANDROID__)
pthread_setname_np(pthread_self(), name);
#else
(void)name;
#endif
}
// Returns the mask that was actually APPLIED, which is 0 when nothing was.
Uint64 ApplyAffinity(Uint64 requested) {
if (requested == 0) return 0;
#if defined(__linux__) || defined(__ANDROID__)
cpu_set_t set;
CPU_ZERO(&set);
Uint applied = 0;
for (Uint cpu = 0; cpu < 64; ++cpu) {
if ((requested & (1ull << cpu)) != 0) {
CPU_SET(cpu, &set);
++applied;
}
}
if (applied == 0) return 0;
if (sched_setaffinity(0, sizeof(set), &set) != 0) return 0;
return requested;
#else
return 0;
#endif
}
Uint32 SpinUsFromConfig() {
#if MOBILEGL_BUILD_DISAGGREGATED
return MG_Config::Ipc.SpinUs;
#else
return Transport::kDefaultSpinUs;
#endif
}
const char* AffinityStringFromConfig() {
#if MOBILEGL_BUILD_DISAGGREGATED
return MG_Config::Ipc.ServerAffinity.c_str();
#else
return "off";
#endif
}
} // namespace
// ---------------------------------------------------------------------------------
// The private backend object
// ---------------------------------------------------------------------------------
MobileGLResult ServerLoop::CreateBackend(BackendType type) {
if (m_backend != nullptr) {
return MOBILEGL_ERR_INVALID_ARGUMENT;
}
switch (type) {
case BackendType::DirectGLES:
m_backend = MakeUnique<MG_Backend::DirectGLES::BackendObject_DirectGLES>();
break;
case BackendType::DirectVulkan:
m_backend = MakeUnique<MG_Backend::DirectVulkan::BackendObject_DirectVulkan>();
break;
default:
// NOT a fallback to DirectGLES. An unknown backend under split has to be refused by
// name: the alternative is a lane that says "split, DirectVulkan" and renders with
// the other backend.
MGLOG_E("MG_Remote server: MG_Config::ActiveBackendType is Unknown; the server role "
"has no backend to own a context with and the session is refused");
return MOBILEGL_ERR_UNSUPPORTED;
}
// Loads the driver entry points and registers the resource op table
// (BackendObject_DirectGLES.cpp:844-851). NO GL CALL AND NO EGL CALL HAPPENS HERE - the
// native context is created and made current later, on the apply thread, when the
// client's eglMakeCurrent crosses as a blocking control request.
m_backend->Initialize();
return MOBILEGL_OK;
}
MG_Backend::BackendObject* ServerLoop::Backend() { return m_backend.get(); }
// ---------------------------------------------------------------------------------
// Start / the loop / Stop
// ---------------------------------------------------------------------------------
MobileGLResult ServerLoop::Start(ServerSession& session) {
if (m_running.load(std::memory_order_acquire)) {
return MOBILEGL_ERR_INVALID_ARGUMENT;
}
if (!session.Accepted()) {
MGLOG_E("MG_Remote server: ServerLoop::Start before ServerSession::Accept - there "
"are no rings to park on");
return MOBILEGL_ERR_NOT_INITIALIZED;
}
m_session = &session;
m_stopRequested.store(false, std::memory_order_release);
{
const std::lock_guard<std::mutex> lock(m_exitMutex);
m_exited = false;
}
m_running.store(true, std::memory_order_release);
m_thread = std::thread([this] { ApplyThreadMain(); });
return MOBILEGL_OK;
}
Bool ServerLoop::Running() const { return m_running.load(std::memory_order_acquire); }
Bool ServerLoop::OnApplyThread() {
ServerLoop& loop = ServerLoopInstance();
return loop.m_running.load(std::memory_order_acquire) &&
loop.m_applyThreadId.load(std::memory_order_acquire) == std::this_thread::get_id();
}
Uint64 ServerLoop::ResolvedAffinityMask() const { return m_affinityMask; }
Uint64 ServerLoop::DrainedRecords() const { return m_drained.load(std::memory_order_acquire); }
Uint64 ServerLoop::ParkCount() const { return m_parks.load(std::memory_order_acquire); }
void ServerLoop::ApplyThreadMain() {
m_applyThreadId.store(std::this_thread::get_id(), std::memory_order_release);
NameThisThread("mgl-srv-apply");
Bool recognised = true;
const char* raw = AffinityStringFromConfig();
const Uint64 requested = RequestedAffinityMask(raw, &recognised);
m_affinityMask = ApplyAffinity(requested);
if (!recognised) {
MGLOG_E("MG_Remote server: MOBILEGL_IPC_SERVER_AFFINITY='%s' is not `auto`, `off` or "
"a number; NO affinity was applied. This is logged rather than defaulted "
"because an affinity that silently did nothing is indistinguishable from "
"one that worked",
raw == nullptr ? "" : raw);
}
// THE RESOLVED MASK, ALWAYS, INCLUDING 0. Contract 5's whole point: the string is what
// an operator typed and the mask is what the kernel took.
MGLOG_I("MG_Remote server: mgl-srv-apply started. MOBILEGL_IPC_SERVER_AFFINITY='%s' "
"requested mask 0x%llx, RESOLVED mask 0x%llx (0 = no affinity applied), spin "
"%u us",
raw == nullptr ? "" : raw, static_cast<unsigned long long>(requested),
static_cast<unsigned long long>(m_affinityMask), SpinUsFromConfig());
ServerSession& session = *m_session;
// The decoder is built HERE, on this thread, because PipeWireDecoder is "not thread
// safe: one decoder on the apply thread, by construction" and its constructor installs
// the process-wide apply hook.
session.Applier().Attach(&session.Control(), m_backend.get());
Transport::RingControl& control = session.Control();
Transport::Doorbell& bell = session.ConsumerDoorbell();
Transport::RingConsumer& ring = session.CommandRing();
const Uint32 spinUs = SpinUsFromConfig();
// THE PARK CONDITION IS THREE THINGS, NOT ONE, AND THAT IS THE WHOLE REASON THIS LOOP
// DOES NOT CALL SessionConsumer::WaitForWork.
//
// WaitForWork's predicate is "a record is waiting" and nothing else. Park a thread on
// kWaitForever with that predicate and neither a control request nor a Stop() can get
// it out: Doorbell::Wait consumes the Notify with one Park, re-tests a condition
// nothing published, finds the bell alive, and parks again - forever. Only
// CondVarDoorbell::Kill() breaks that, and Kill is the CLIENT's teardown call, not
// something an EGL make-current request may perform. So the predicate carries all
// three arming conditions and the doorbell wakes the thread for any of them.
const auto ready = [this, &control, &ring] {
return control.cmdHead.load(std::memory_order_acquire) != ring.LocalTail() ||
m_stopRequested.load(std::memory_order_acquire) || ControlIsPending();
};
for (;;) {
PumpControlRequest();
if (m_stopRequested.load(std::memory_order_acquire)) break;
DrainRing();
if (m_stopRequested.load(std::memory_order_acquire)) break;
if (ready()) continue;
m_parks.fetch_add(1, std::memory_order_acq_rel);
const bool woke = bell.Wait(control.consumerParked, ready, spinUs, Transport::kWaitForever);
if (!woke) {
// Wait returns false only on a dead bell or an expired deadline, and this park
// has no deadline. A dead bell IS the shutdown signal (table 3's teardown step
// 2); treating it as anything else would spin at full clock for ever, since
// parking on a dead bell no longer blocks.
if (bell.Dead()) {
MGLOG_D("MG_Remote server: the consumer doorbell is dead; mgl-srv-apply is "
"shutting down");
break;
}
MGLOG_E("MG_Remote server: Doorbell::Wait(kWaitForever) returned false on a live "
"bell - that is impossible by Doorbell.h:139-178 and means the bell's "
"Dead() answer moved under the waiter. Shutting the loop down rather "
"than spinning");
break;
}
}
// Whatever is still queued gets applied before the context goes. The client's own
// drain (ClientSession::Stop step 1) normally empties the ring first and is BOUNDED, so
// a timeout there leaves records here; applying them costs nothing and dropping them
// would leave the emitter's var-tails referenced by records nobody ever read.
PumpControlRequest();
DrainRing();
// THE BACKEND IS DESTROYED ON THIS THREAD, WHILE IT IS STILL THE CONTEXT OWNER.
// ~BackendObject_DirectGLES calls DestroyEGLContext (BackendObject_DirectGLES.cpp:
// 833-835), which runs eglMakeCurrent(NO_SURFACE) / eglDestroyContext / eglTerminate.
// Those must happen on the thread eglMakeCurrent was issued from; doing it on the app
// thread - which is what pActiveBackendObject.reset() at MobileGL/Init.cpp:68 would do
// - destroys a context this thread still holds current.
session.Applier().Detach();
if (m_backend != nullptr) {
MGLOG_I("MG_Remote server: destroying the server's BackendObject on mgl-srv-apply, "
"which is the context owner");
m_backend.reset();
}
// Anything still parked in RunOnApplyThread has to be answered rather than left
// waiting: this thread is the only thing that could have run it.
{
const std::lock_guard<std::mutex> lock(m_controlMutex);
if (m_controlPending) {
m_controlPending = false;
m_controlFinished = true;
m_controlResult = MOBILEGL_ERR_NOT_INITIALIZED;
MGLOG_E("MG_Remote server: a control request was still posted when mgl-srv-apply "
"exited; it is answered NOT_INITIALIZED rather than left blocking");
}
}
m_controlDone.notify_all();
m_running.store(false, std::memory_order_release);
SignalExited();
}
Bool ServerLoop::ControlIsPending() const {
const std::lock_guard<std::mutex> lock(const_cast<std::mutex&>(m_controlMutex));
return m_controlPending;
}
Bool ServerLoop::PumpControlRequest() {
ControlWork work = nullptr;
void* user = nullptr;
{
const std::lock_guard<std::mutex> lock(m_controlMutex);
if (!m_controlPending) return false;
work = m_controlWork;
user = m_controlUser;
}
const MobileGLResult result = work == nullptr ? MOBILEGL_ERR_INVALID_ARGUMENT : work(user);
{
const std::lock_guard<std::mutex> lock(m_controlMutex);
m_controlResult = result;
m_controlPending = false;
m_controlFinished = true;
}
m_controlDone.notify_all();
return true;
}
Uint64 ServerLoop::DrainRing() {
ServerSession& session = *m_session;
Transport::SessionConsumer& consumer = session.Consumer();
PipeApplier& applier = session.Applier();
Uint64 applied = 0;
for (;;) {
bool corrupt = false;
const bool popped = consumer.ApplyOne(
[this, &applier](const Transport::RingRecordView& record) {
applier.ApplyOne(record);
// THE TALLY MOVES HERE, INSIDE THE CALLBACK, AND NOT AFTER THE BATCH. s1's
// SessionConsumer::ApplyOne publishes appliedSeq the instant this callback
// returns, and publishing appliedSeq is what releases the client from the
// verb barrier (R-1). Anything this thread records about the record AFTER
// that publish is visible to the client only eventually - and a diagnostic
// that can lag the watermark it describes is the exact shape of the
// LeaveApplier race PipeApplier::ApplyOne's block describes, one level up.
// The first version of this function tallied once per batch, below, and
// AClearRecordCrossesAndIsStampedAsAVerbBoundary /
// TheSessionWatermarkAndTheDecoderTallyAgreeAfterEveryRecord read
// DrainedRecords() one behind appliedSeq on 1 run in ~40 under `-j 8`.
// Per-record, before the publish, it can never be behind.
m_drained.fetch_add(1, std::memory_order_acq_rel);
},
&corrupt);
if (corrupt) {
// Ring.h's own rule: a header the producer could not have written is
// Fatal{ProtocolCorruption}, never a retry. Retrying re-reads the same bytes
// for ever; skipping desynchronises seq, and seq IS the reply-slot id.
MGLOG_F("MGPipe: Fatal{ProtocolCorruption, \"SEG_CMD record header\"} - the "
"consumer refused a record header at applied seq %llu",
static_cast<unsigned long long>(consumer.AppliedSeq()));
std::abort();
}
if (!popped) break;
++applied;
}
if (applied != 0) {
// THE TWO TALLIES MUST AGREE, AND THAT IS WHAT MAKES R-9's BATCHING BAN CHECKABLE.
// RingControl::appliedSeq has one writer (SessionConsumer::ApplyOne, +1 per record)
// and PipeWireDecoder keeps its own count; a batched publish would move one and not
// the other, which a single counter could not have told apart (w1-v1 5).
if (applier.DecoderAppliedSeq() != consumer.AppliedSeq()) {
MGLOG_F("MGPipe: Fatal{ProtocolCorruption, \"appliedSeq batched\"} - the "
"session's watermark is %llu and the decoder applied %llu records. P5 "
"forbids batching appliedSeq (R-9): the verb barrier's waiter reads it, "
"and a watermark ahead of the decoder promises work that has not run",
static_cast<unsigned long long>(consumer.AppliedSeq()),
static_cast<unsigned long long>(applier.DecoderAppliedSeq()));
std::abort();
}
// RETIRE. MANDATORY, not optional: RingProducer::FreeBytes() reclaims against
// retiredTail only, and w1's SEG_STAGE linear allocator reclaims on retiredSeq - so
// a loop that applies and never retires ends the first MOBILEGL_IPC_STAGE_MB of
// staging in Fatal{RingOverrun, "SEG_STAGE"} (w1-v1 5). Once per drain batch, not
// once per record: retiring LATE is always legal, retiring EARLY never is.
consumer.RetireThrough(consumer.AppliedSeq());
// LEAVING THE APPLIER (p1's M-5) IS *NOT* DONE HERE. It is done inside
// PipeApplier::ApplyOne, before s1's SessionConsumer::ApplyOne publishes appliedSeq
// - see the block there. A clear at this point races the client, which the barrier
// has already released by then.
}
return applied;
}
MobileGLResult ServerLoop::RunOnApplyThread(ControlWork work, void* user) {
if (work == nullptr) return MOBILEGL_ERR_INVALID_ARGUMENT;
// RE-ENTRANCY IS NOT A DEADLOCK. The teardown path posts from the apply thread itself -
// ~BackendObject_DirectGLES reaches ReleaseEGLResources - and so does anything the
// applier calls that wants "run this where the context is". Running inline is the
// correct answer there and the only non-hanging one.
if (OnApplyThread()) return work(user);
// NO THREAD YET, OR ALREADY GONE: run inline on the caller. That is right for the
// window between MG_Backend::Init()'s hook and ClientSession::Start (the backend object
// exists, the thread does not, and nothing has made a context current), and for the
// window after Stop(). It is NOT a silent fallback to monolith: the thread's absence in
// those two windows is a fact about the lifecycle, not about the transport.
if (!m_running.load(std::memory_order_acquire)) return work(user);
const std::lock_guard<std::mutex> callerLock(m_callerMutex);
{
std::unique_lock<std::mutex> lock(m_controlMutex);
m_controlWork = work;
m_controlUser = user;
m_controlPending = true;
m_controlFinished = false;
}
// Publish THEN ring, in that order and never the other (Doorbell.h:186-193). The bell
// is rung unconditionally rather than through NotifyIfParked because this side does not
// know whether the apply thread is parked or spinning, and CondVarDoorbell remembers a
// wakeup that arrives while nobody is waiting.
if (m_session != nullptr) {
m_session->ConsumerDoorbell().Notify();
}
std::unique_lock<std::mutex> lock(m_controlMutex);
m_controlDone.wait(lock, [this] { return m_controlFinished; });
return m_controlResult;
}
void ServerLoop::SignalExited() {
{
const std::lock_guard<std::mutex> lock(m_exitMutex);
m_exited = true;
}
m_exitCv.notify_all();
}
void ServerLoop::Stop() {
if (!m_thread.joinable()) {
// Never started, or already stopped. The backend may still exist - the hook builds
// it before the thread - and it has to go somewhere, so it goes here, on whatever
// thread called Stop. No context was ever made current from another thread in that
// case, which is exactly the condition that makes this safe.
if (m_backend != nullptr) m_backend.reset();
m_running.store(false, std::memory_order_release);
return;
}
m_stopRequested.store(true, std::memory_order_release);
if (m_session != nullptr) {
// The bell may already be dead - ClientSession::Stop calls transport->Shutdown()
// first, which is what table 3's step 2 requires - and Notify on a dead bell is
// harmless. Ringing anyway covers the paths that Stop without a Kill.
m_session->ConsumerDoorbell().Notify();
}
// THE JOIN IS BOUNDED. std::thread::join has no deadline, so a lost wakeup would wedge
// CI rather than fail it; the thread signals m_exited last and this waits with the same
// five seconds InProcessTransportTest.cpp:344 uses.
Bool exited = false;
{
std::unique_lock<std::mutex> lock(m_exitMutex);
exited = m_exitCv.wait_for(lock, std::chrono::milliseconds(kJoinTimeoutMs),
[this] { return m_exited; });
}
if (!exited) {
// ABORT, NOT DETACH. A detached apply thread still owns the EGL context and would
// run on into the client's teardown, reading rings the client is about to unmap -
// a use-after-free whose only symptom is an intermittent crash somewhere else.
// Aborting here is red, immediate, and names the cause.
MGLOG_F("MGPipe: Fatal{ApplyThreadJoinTimeout} - mgl-srv-apply did not exit within "
"%u ms of Stop(). It parks on Doorbell::Wait(kWaitForever), which only "
"CondVarDoorbell::Kill() can break (Doorbell.h:211-221, table 3 step 2), so "
"this is a lost wakeup and not a slow thread. Aborting rather than "
"detaching: a detached apply thread still owns the context and would read "
"rings the client is about to unmap",
kJoinTimeoutMs);
std::abort();
}
m_thread.join();
m_applyThreadId.store(std::thread::id{}, std::memory_order_release);
m_running.store(false, std::memory_order_release);
m_session = nullptr;
} }
ServerLoop& ServerLoopInstance() { ServerLoop& ServerLoopInstance() {
@@ -44,6 +508,257 @@ namespace MobileGL::MG_Remote::Server {
return instance; return instance;
} }
#undef MGP5_C0_STUB // ---------------------------------------------------------------------------------
// The twelve EGL forwarders
// ---------------------------------------------------------------------------------
namespace {
// One captureless trampoline for every call: ControlWork is a raw function pointer
// plus a void*, not a std::function, because these run on the TEARDOWN path and the
// teardown path may not allocate (ID-8 exists because frontend destructors reach here
// from exit handlers).
template <class Args>
MobileGLResult RunOnApply(Args& args) {
return ServerLoopInstance().RunOnApplyThread(
+[](void* user) -> MobileGLResult { return static_cast<Args*>(user)->Run(); },
&args);
}
// Null means the hook never ran or the session is already down. Every forwarder
// answers false / no-op rather than dereferencing: a client that calls eglMakeCurrent
// on a process whose split bring-up failed must see a refusal, not a crash.
MG_Backend::BackendObject* ServerBackendOrNull() { return ServerLoopInstance().Backend(); }
} // namespace
Bool ServerInitializeEGLDisplay(EGLDisplay dpy, EGLint* major, EGLint* minor) {
struct Args {
EGLDisplay dpy;
EGLint* major;
EGLint* minor;
Bool ok = false;
MobileGLResult Run() {
MG_Backend::BackendObject* backend = ServerBackendOrNull();
if (backend == nullptr) return MOBILEGL_ERR_NOT_INITIALIZED;
ok = backend->InitializeEGLDisplay(dpy, major, minor);
return MOBILEGL_OK;
}
} args{dpy, major, minor};
return RunOnApply(args) == MOBILEGL_OK && args.ok;
}
Bool ServerCreateEGLWindowSurface(EGLSurface surface, const MG_Backend::WindowHandle& handle) {
struct Args {
EGLSurface surface;
const MG_Backend::WindowHandle* handle;
Bool ok = false;
MobileGLResult Run() {
MG_Backend::BackendObject* backend = ServerBackendOrNull();
if (backend == nullptr) return MOBILEGL_ERR_NOT_INITIALIZED;
ok = backend->CreateEGLWindowSurface(surface, *handle);
return MOBILEGL_OK;
}
} args{surface, &handle};
return RunOnApply(args) == MOBILEGL_OK && args.ok;
}
Bool ServerResizeEGLWindowSurface(EGLSurface surface, Uint32 width, Uint32 height) {
struct Args {
EGLSurface surface;
Uint32 width;
Uint32 height;
Bool ok = false;
MobileGLResult Run() {
MG_Backend::BackendObject* backend = ServerBackendOrNull();
if (backend == nullptr) return MOBILEGL_ERR_NOT_INITIALIZED;
ok = backend->ResizeEGLWindowSurface(surface, width, height);
return MOBILEGL_OK;
}
} args{surface, width, height};
return RunOnApply(args) == MOBILEGL_OK && args.ok;
}
Bool ServerCreateEGLPbufferSurface(EGLSurface surface, EGLint width, EGLint height) {
struct Args {
EGLSurface surface;
EGLint width;
EGLint height;
Bool ok = false;
MobileGLResult Run() {
MG_Backend::BackendObject* backend = ServerBackendOrNull();
if (backend == nullptr) return MOBILEGL_ERR_NOT_INITIALIZED;
ok = backend->CreateEGLPbufferSurface(surface, width, height);
return MOBILEGL_OK;
}
} args{surface, width, height};
return RunOnApply(args) == MOBILEGL_OK && args.ok;
}
Bool ServerMakeEGLCurrent(EGLDisplay dpy, EGLSurface draw, EGLSurface read, EGLContext ctx) {
struct Args {
EGLDisplay dpy;
EGLSurface draw;
EGLSurface read;
EGLContext ctx;
Bool ok = false;
MobileGLResult Run() {
MG_Backend::BackendObject* backend = ServerBackendOrNull();
if (backend == nullptr) return MOBILEGL_ERR_NOT_INITIALIZED;
// THE ONE eglMakeCurrent OF THE PROCESS'S LIFE, ON THIS THREAD. Every later
// client-side eglMakeCurrent onto the same surface finds the context already
// current here and costs nothing; the owner slot is written once.
ok = backend->MakeEGLCurrent(dpy, draw, read, ctx);
if (!ok) return MOBILEGL_OK;
// R-12, arm (a): the caps snapshot is REPUBLISHED because InitCapabilities has
// now run for real. DirectGLES has no OnCapsInvalidated producer at all, and
// c0's answer is that a SECOND arrival IS the invalidation - so the client's
// mirror is refreshed with no dev-shaped backend edit and with no eleventh
// MGPipeCallbacks slot (MGPipeCallbacks.h:56-58's static_assert exists to make
// that cost visible).
ServerSession* session = ServerSession::Active();
if (session != nullptr && session->Accepted()) {
const MobileGLResult published = session->PublishCapsSnapshot();
if (published != MOBILEGL_OK) {
MGLOG_E("MG_Remote server: the post-make-current CapsSnapshot could not "
"be published (rc=%d); the client's mirror still holds the empty "
"snapshot Accept() sent before any context existed",
static_cast<int>(published));
}
}
return MOBILEGL_OK;
}
} args{dpy, draw, read, ctx};
return RunOnApply(args) == MOBILEGL_OK && args.ok;
}
Bool ServerSwapEGLBuffers(EGLDisplay dpy, EGLSurface draw) {
struct Args {
EGLDisplay dpy;
EGLSurface draw;
Bool ok = false;
MobileGLResult Run() {
MG_Backend::BackendObject* backend = ServerBackendOrNull();
if (backend == nullptr) return MOBILEGL_ERR_NOT_INITIALIZED;
ok = backend->SwapEGLBuffers(dpy, draw);
return MOBILEGL_OK;
}
} args{dpy, draw};
return RunOnApply(args) == MOBILEGL_OK && args.ok;
}
void ServerSetEGLSwapInterval(Int interval) {
struct Args {
Int interval;
MobileGLResult Run() {
MG_Backend::BackendObject* backend = ServerBackendOrNull();
if (backend == nullptr) return MOBILEGL_ERR_NOT_INITIALIZED;
backend->SetEGLSwapInterval(interval);
return MOBILEGL_OK;
}
} args{interval};
(void)RunOnApply(args);
}
void ServerReleaseEGLSurface(EGLSurface surface) {
struct Args {
EGLSurface surface;
MobileGLResult Run() {
MG_Backend::BackendObject* backend = ServerBackendOrNull();
if (backend == nullptr) return MOBILEGL_ERR_NOT_INITIALIZED;
backend->ReleaseEGLSurface(surface);
return MOBILEGL_OK;
}
} args{surface};
(void)RunOnApply(args);
}
void ServerReleaseEGLResources() {
// BLOCKING BY CONTRACT. EGLImpl.cpp:326 calls this on the app thread and then, if no
// display and no context are left, calls MobileGL::Destroy() at :333. For DirectGLES it
// runs DestroyEGLContext - eglMakeCurrent(NO_SURFACE), eglDestroyContext, eglTerminate -
// and those must happen on the thread that made the context current. A fire-and-forget
// here lets Destroy() walk on while the server still holds the context, which is
// scout-install 5.3's named hazard.
struct Args {
MobileGLResult Run() {
MG_Backend::BackendObject* backend = ServerBackendOrNull();
if (backend == nullptr) return MOBILEGL_ERR_NOT_INITIALIZED;
backend->ReleaseEGLResources();
return MOBILEGL_OK;
}
} args{};
(void)RunOnApply(args);
}
Bool ServerInitCapabilities() {
struct Args {
Bool ok = false;
MobileGLResult Run() {
MG_Backend::BackendObject* backend = ServerBackendOrNull();
if (backend == nullptr) return MOBILEGL_ERR_NOT_INITIALIZED;
ok = backend->InitCapabilities();
if (!ok) return MOBILEGL_OK;
ServerSession* session = ServerSession::Active();
if (session != nullptr && session->Accepted()) {
(void)session->PublishCapsSnapshot();
}
return MOBILEGL_OK;
}
} args{};
return RunOnApply(args) == MOBILEGL_OK && args.ok;
}
Bool ServerInitWindowSurface() {
struct Args {
Bool ok = false;
MobileGLResult Run() {
MG_Backend::BackendObject* backend = ServerBackendOrNull();
if (backend == nullptr) return MOBILEGL_ERR_NOT_INITIALIZED;
ok = backend->InitWindowSurface();
return MOBILEGL_OK;
}
} args{};
return RunOnApply(args) == MOBILEGL_OK && args.ok;
}
void ServerSetWindowHandle(const MG_Backend::WindowHandle& handle) {
struct Args {
const MG_Backend::WindowHandle* handle;
MobileGLResult Run() {
MG_Backend::BackendObject* backend = ServerBackendOrNull();
if (backend == nullptr) return MOBILEGL_ERR_NOT_INITIALIZED;
backend->SetWindowHandle(*handle);
return MOBILEGL_OK;
}
} args{&handle};
(void)RunOnApply(args);
}
} // namespace MobileGL::MG_Remote::Server } // namespace MobileGL::MG_Remote::Server
// ---------------------------------------------------------------------------------
// The weak placeholder for package c1's remote backend object
// ---------------------------------------------------------------------------------
//
// MG_Backend/Init.cpp's hook calls MG_Remote::Client::CreateRemoteBackendObject(), which is
// c1's BackendObject_Remote and does not exist while v1 is written. A WEAK definition here
// lets v1 compile, link and be tested today, and c1's strong definition displaces it at link
// time with no edit anywhere.
//
// IT ABORTS BY NAME AND DOES NOT RETURN A WORKING MONOLITH OBJECT. That distinction is the
// whole point: a placeholder that handed back a BackendObject_DirectGLES would give a lane
// called "split" a correct picture produced entirely by the monolith path, which is
// ARCHITECTURE.md 10.3's failure and the one this phase exists to make impossible.
#if defined(__GNUC__) || defined(__clang__)
namespace MobileGL::MG_Remote::Client {
__attribute__((weak)) UniquePtr<MG_Backend::BackendObject> CreateRemoteBackendObject() {
MGLOG_F("MGPipe: Fatal{UnimplementedRemoteBackendObject} - MG_Backend::Init()'s split "
"hook asked for the client's BackendObject_Remote and only v1's weak "
"placeholder is linked in. That object is package c1's (BRIEF 5); until it "
"lands there is no client role, and this build refuses to substitute the "
"monolith backend for it");
std::abort();
}
} // namespace MobileGL::MG_Remote::Client
#endif
MobileGL/MG_Remote/Server/ServerLoop.h
+124 -1
View File
@@ -45,6 +45,11 @@
#include "ServerSession.h" #include "ServerSession.h"
#include <atomic>
#include <condition_variable>
#include <mutex>
#include <thread>
namespace MobileGL::MG_Remote::Server { namespace MobileGL::MG_Remote::Server {
class ServerLoop { class ServerLoop {
@@ -81,11 +86,129 @@ namespace MobileGL::MG_Remote::Server {
using ControlWork = MobileGLResult (*)(void* user); using ControlWork = MobileGLResult (*)(void* user);
MobileGLResult RunOnApplyThread(ControlWork work, void* user); MobileGLResult RunOnApplyThread(ControlWork work, void* user);
// ---- v1's additions beyond c0's signature block ---------------------------------
// Constructs the SERVER ROLE's private BackendObject and runs its non-GL Initialize().
// Called from MG_Backend::Init()'s single hook, BEFORE ClientSession::Start(), because
// ServerSession::Accept() publishes the first CapsSnapshot from it and because the two
// CallMask halves - which have no default and Fatal when unset (ServerSession.h) - are
// answered from what this backend is.
//
// NO GL AND NO EGL HAPPENS HERE. BackendObject_DirectGLES::Initialize() loads the
// driver's entry points; the native context does not exist until the client's first
// eglMakeCurrent crosses as a blocking control request and runs on the apply thread.
// That split is what lets the backend object be BUILT on the app thread while its
// context is never OWNED by it.
MobileGLResult CreateBackend(BackendType type);
// True on the apply thread itself. RunOnApplyThread uses it to run inline rather than
// deadlock when the apply thread posts to itself - which the EGL teardown path does,
// because ~BackendObject_DirectGLES runs THERE and reaches ReleaseEGLResources.
static Bool OnApplyThread();
// The CPU mask MOBILEGL_IPC_SERVER_AFFINITY resolved to and sched_setaffinity accepted.
// 0 means "no affinity was applied" - the honest answer for `off`, for a platform with
// no affinity call, and for a failed syscall - and is exactly why the RESOLVED mask is
// logged rather than the string an operator typed.
Uint64 ResolvedAffinityMask() const;
// Diagnostics the tests read. DrainedRecords is how many records this thread has handed
// to the applier; ParkCount how many times it actually parked. A shutdown test that
// asserts only "Stop() returned" cannot tell a thread that parked and was woken by Kill
// from one that never parked at all - which is the R-16 shape of a check that cannot
// fail for its own reason.
Uint64 DrainedRecords() const;
Uint64 ParkCount() const;
private: private:
void ApplyThreadMain();
// Part of the apply thread's park predicate: a posted control request must be able to
// un-park a thread waiting on kWaitForever, which a Notify alone cannot do.
Bool ControlIsPending() const;
// Runs a posted control request, if there is one. Returns true if it ran one.
Bool PumpControlRequest();
// Pops and applies every record currently in the ring; returns how many it applied.
Uint64 DrainRing();
void SignalExited();
ServerSession* m_session = nullptr; ServerSession* m_session = nullptr;
Bool m_running = false; std::atomic<Bool> m_running{false};
std::atomic<Bool> m_stopRequested{false};
std::thread m_thread;
std::atomic<std::thread::id> m_applyThreadId{};
// The private backend object. Destroyed ON the apply thread while it still owns the
// context - see Stop().
UniquePtr<MG_Backend::BackendObject> m_backend;
// The blocking control mailbox. ONE slot, because the verb barrier already leaves one
// client thread runnable at a time; m_callerMutex serialises anything that is not.
std::mutex m_callerMutex;
std::mutex m_controlMutex;
std::condition_variable m_controlPosted;
std::condition_variable m_controlDone;
ControlWork m_controlWork = nullptr;
void* m_controlUser = nullptr;
MobileGLResult m_controlResult = MOBILEGL_OK;
Bool m_controlPending = false;
Bool m_controlFinished = false;
// The BOUNDED join's other half. std::thread::join has no deadline, so a lost wakeup
// would wedge CI rather than fail it; the thread signals here last and Stop() waits
// with a deadline (InProcessTransportTest.cpp:344's five seconds).
std::mutex m_exitMutex;
std::condition_variable m_exitCv;
Bool m_exited = false;
Uint64 m_affinityMask = 0;
std::atomic<Uint64> m_drained{0};
std::atomic<Uint64> m_parks{0};
}; };
ServerLoop& ServerLoopInstance(); ServerLoop& ServerLoopInstance();
// ---------------------------------------------------------------------------------
// THE EGL OWNERSHIP MOVE - the part that can sink the phase, expressed as twelve calls
// ---------------------------------------------------------------------------------
//
// Under split the app thread must never reach the driver's eglMakeCurrent. Today it does:
// EGLImpl.cpp:284 -> BackendObject_DirectGLES.cpp:963 -> DirectGLES.cpp:11925, and the
// owner slot g_backendContextOwnerThread (DirectGLES.cpp:11865) is stamped with whatever
// thread got there. So BackendObject_Remote's nine EGL virtuals - package c1's - call these
// twelve, each of which is a BLOCKING control request that runs the SERVER's backend object
// on mgl-srv-apply. eglMakeCurrent then runs ONCE, on that thread, and is never released:
// g_backendContextOwnerThread is written once, DirectGLES.cpp:11933-11953's six cache
// invalidations become a one-off startup cost instead of a per-migration storm, the
// per-frame EGL re-verification stamp is permanently true, and the 16
// IsBackendContextCurrentOnThisThread() sites plus the 16 CanTouchGLNow() sites answer TRUE
// on the server instead of silently degrading.
//
// TWO OF THEM MUST BLOCK OR THE PROCESS TEARS ITS OWN CONTEXT DOWN UNDER ITSELF:
// ReleaseEGLResources (reached from EGLImpl.cpp:326, which for DirectGLES runs
// DestroyEGLContext) and ~BackendObject_DirectGLES (reached from
// pActiveBackendObject.reset() at MobileGL/Init.cpp:68). Both are blocking here - the first
// by being one of these calls, the second because ServerLoop::Stop() destroys the private
// backend ON the apply thread before that thread exits and Stop() itself waits.
//
// WHY THEY ARE FREE FUNCTIONS AND NOT MEMBERS: c1 needs exactly this surface and nothing
// else of the server, so the seam between the two packages is a list of twelve signatures
// rather than a class with a lifecycle.
Bool ServerInitializeEGLDisplay(EGLDisplay dpy, EGLint* major, EGLint* minor);
Bool ServerCreateEGLWindowSurface(EGLSurface surface, const MG_Backend::WindowHandle& handle);
Bool ServerResizeEGLWindowSurface(EGLSurface surface, Uint32 width, Uint32 height);
Bool ServerCreateEGLPbufferSurface(EGLSurface surface, EGLint width, EGLint height);
// Also RE-PUBLISHES THE CAPS SNAPSHOT on success (R-12). BackendObject::MakeEGLCurrent runs
// InitCapabilities() on the first make-current per surface (BackendObject.cpp:341-347), so
// this is the moment the server's answers stop being the empty ones Accept() published -
// and a SECOND arrival IS the invalidation signal, which is how DirectGLES, which has no
// OnCapsInvalidated producer at all, tells the client without a dev-shaped backend edit.
Bool ServerMakeEGLCurrent(EGLDisplay dpy, EGLSurface draw, EGLSurface read, EGLContext ctx);
Bool ServerSwapEGLBuffers(EGLDisplay dpy, EGLSurface draw);
void ServerSetEGLSwapInterval(Int interval);
void ServerReleaseEGLSurface(EGLSurface surface);
void ServerReleaseEGLResources();
Bool ServerInitCapabilities();
Bool ServerInitWindowSurface();
void ServerSetWindowHandle(const MG_Backend::WindowHandle& handle);
} // namespace MobileGL::MG_Remote::Server } // namespace MobileGL::MG_Remote::Server