add trigger gc api (#379)

* add trigger gc api
* support trigger gc for a specific pg

Author: JacksonYao287

src/lib/homestore_backend/gc_manager.cpp

@@ -122,7 +122,10 @@ void GCManager::start() {
         gc_actor->start();
         LOGINFOMOD(gcmgr, "start gc actor for pdev={}", pdev_id);
     }
+    start_gc_scan_timer();
+}
 
+void GCManager::start_gc_scan_timer() {
     const auto gc_scan_interval_sec = HS_BACKEND_DYNAMIC_CONFIG(gc_scan_interval_sec);
 
     // the initial idea here is that we want gc timer to run in a reactor that not shared with other fibers that
@@ -146,9 +149,7 @@ void GCManager::start() {
     LOGINFOMOD(gcmgr, "gc scheduler timer has started, interval is set to {} seconds", gc_scan_interval_sec);
 }
 
-bool GCManager::is_started() { return m_gc_timer_hdl != iomgr::null_timer_handle; }
-
-void GCManager::stop() {
+void GCManager::stop_gc_scan_timer() {
     if (m_gc_timer_hdl == iomgr::null_timer_handle) {
         LOGWARNMOD(gcmgr, "gc scheduler timer is not running, no need to stop it");
         return;
@@ -162,6 +163,10 @@ void GCManager::stop() {
         m_gc_timer_hdl = iomgr::null_timer_handle;
     });
     m_gc_timer_fiber = nullptr;
+}
+
+void GCManager::stop() {
+    stop_gc_scan_timer();
 
     for (const auto& [pdev_id, gc_actor] : m_pdev_gc_actors) {
         gc_actor->stop();
@@ -170,9 +175,20 @@ void GCManager::stop() {
 }
 
 folly::SemiFuture< bool > GCManager::submit_gc_task(task_priority priority, chunk_id_t chunk_id) {
-    if (!is_started()) return folly::makeFuture< bool >(false);
+    auto ex_vchunk = m_chunk_selector->get_extend_vchunk(chunk_id);
+    if (ex_vchunk == nullptr) {
+        LOGERRORMOD(gcmgr, "chunk {} not found when submit gc task!", chunk_id);
+        return folly::makeFuture< bool >(false);
+    }
+
+    // if the chunk has no garbage to be reclaimed, we don`t need to gc it , return true directly
+    const auto defrag_blk_num = ex_vchunk->get_defrag_nblks();
+    if (!defrag_blk_num && task_priority::normal == priority) {
+        LOGERRORMOD(gcmgr, "chunk {} has no garbage to be reclaimed, skip gc for this chunk!", chunk_id);
+        return folly::makeFuture< bool >(true);
+    }
 
-    auto pdev_id = m_chunk_selector->get_extend_vchunk(chunk_id)->get_pdev_id();
+    auto pdev_id = ex_vchunk->get_pdev_id();
     auto it = m_pdev_gc_actors.find(pdev_id);
     if (it == m_pdev_gc_actors.end()) {
         LOGINFOMOD(gcmgr, "pdev gc actor not found for pdev_id={}, chunk={}", pdev_id, chunk_id);
@@ -334,6 +350,11 @@ void GCManager::pdev_gc_actor::add_reserved_chunk(
 }
 
 folly::SemiFuture< bool > GCManager::pdev_gc_actor::add_gc_task(uint8_t priority, chunk_id_t move_from_chunk) {
+    if (m_is_stopped.load()) {
+        LOGWARNMOD(gcmgr, "pdev gc actor for pdev_id={} is not started yet or already stopped, cannot add gc task!",
+                   m_pdev_id);
+        return folly::makeSemiFuture< bool >(false);
+    }
     auto EXvchunk = m_chunk_selector->get_extend_vchunk(move_from_chunk);
     // it does not belong to any pg, so we don't need to gc it.
     if (!EXvchunk->m_pg_id.has_value()) {

src/lib/homestore_backend/gc_manager.hpp

@@ -310,7 +310,11 @@ class GCManager {
 
     void start();
     void stop();
-    bool is_started();
+
+    // the following two functions should not be called concurrently. if we need to call them concurrently, we need to
+    // add lock to protect
+    void start_gc_scan_timer();
+    void stop_gc_scan_timer();
 
     void scan_chunks_for_gc();
     void drain_pg_pending_gc_task(const pg_id_t pg_id);

src/lib/homestore_backend/hs_http_manager.cpp

@@ -64,7 +64,17 @@ HttpManager::HttpManager(HSHomeObject& ho) : ho_(ho) {
         {Pistache::Http::Method::Get, "/api/v1/chunk/dump",
          Pistache::Rest::Routes::bind(&HttpManager::dump_chunk, this)},
         {Pistache::Http::Method::Get, "/api/v1/shard/dump",
-         Pistache::Rest::Routes::bind(&HttpManager::dump_shard, this)}};
+         Pistache::Rest::Routes::bind(&HttpManager::dump_shard, this)},
+
+        // we support triggering gc for:
+        // 1 all the chunks in all the pg: no input param
+        // 2 all the chunks in a specific pg: input param is pg_id
+        // 3 a specific chunk: input param is pchunk_id
+
+        {Pistache::Http::Method::Post, "/api/v1/trigger_gc",
+         Pistache::Rest::Routes::bind(&HttpManager::trigger_gc, this)},
+        {Pistache::Http::Method::Get, "/api/v1/gc_job_status",
+         Pistache::Rest::Routes::bind(&HttpManager::get_gc_job_status, this)}};
 
     auto http_server = ioenvironment.get_http_server();
     if (!http_server) {
@@ -476,6 +486,290 @@ void HttpManager::exit_pg(const Pistache::Rest::Request& request, Pistache::Http
     response.send(Pistache::Http::Code::Ok, "Exit pg request submitted");
 }
 
+void HttpManager::trigger_gc(const Pistache::Rest::Request& request, Pistache::Http::ResponseWriter response) {
+    auto gc_mgr = ho_.gc_manager();
+    if (!gc_mgr) {
+        response.send(Pistache::Http::Code::Internal_Server_Error, "GC manager not available");
+        return;
+    }
+
+    auto chunk_selector = ho_.chunk_selector();
+    if (!chunk_selector) {
+        response.send(Pistache::Http::Code::Internal_Server_Error, "Chunk selector not available");
+        return;
+    }
+
+    const auto chunk_id_param = request.query().get("chunk_id");
+    const auto pg_id_param = request.query().get("pg_id");
+
+    if (chunk_id_param && !chunk_id_param.value().empty()) {
+        // trigger gc for a specific chunk, the chunk_id is pchunk_id, not vchunk_id
+        uint32_t chunk_id = std::stoul(chunk_id_param.value());
+        LOGINFO("Received trigger_gc request for chunk_id {}", chunk_id);
+
+        auto chunk = chunk_selector->get_extend_vchunk(chunk_id);
+        if (!chunk) {
+            nlohmann::json error;
+            error["chunk_id"] = chunk_id;
+            error["error"] = "Chunk not found";
+            response.send(Pistache::Http::Code::Not_Found, error.dump());
+            return;
+        }
+
+        if (!chunk->m_pg_id.has_value()) {
+            nlohmann::json error;
+            error["chunk_id"] = chunk_id;
+            error["error"] = "Chunk belongs to no pg";
+            response.send(Pistache::Http::Code::Not_Found, error.dump());
+            return;
+        }
+
+        const auto pg_id = chunk->m_pg_id.value();
+        nlohmann::json result;
+        const auto job_id = generate_job_id();
+
+        result["chunk_id"] = chunk_id;
+        result["pg_id"] = pg_id;
+        result["job_id"] = job_id;
+
+        if (chunk->m_state == ChunkState::GC) {
+            result["message"] = "chunk is already under GC now, this task will not be executed!";
+            response.send(Pistache::Http::Code::Ok, result.dump());
+            return;
+        }
+        result["message"] = "GC triggered for chunk, pls query job status using gc_job_status API";
+
+        // return response before starting the GC so that we don't block the client.
+        response.send(Pistache::Http::Code::Accepted, result.dump());
+
+        auto job_info = std::make_shared< GCJobInfo >(job_id, pg_id, chunk_id);
+        {
+            std::lock_guard lock(gc_job_mutex_);
+            gc_jobs_map_.set(job_id, job_info);
+        }
+
+        // sumbit gc task for this chunk
+
+        // Clear in-memory requests only for emergent priority chunks (chunks with open shards)
+        auto hs_pg = const_cast< HSHomeObject::HS_PG* >(ho_.get_hs_pg(pg_id));
+        RELEASE_ASSERT(hs_pg, "HS PG {} not found during GC job {}", pg_id, job_id);
+        auto repl_dev = hs_pg->repl_dev_;
+        repl_dev->quiesce_reqs();
+        repl_dev->clear_chunk_req(chunk_id);
+        const auto priority = chunk->m_state == ChunkState::INUSE ? task_priority::emergent : task_priority::normal;
+
+        gc_mgr->submit_gc_task(priority, chunk_id)
+            .via(&folly::InlineExecutor::instance())
+            .thenValue([this, job_info, repl_dev](bool res) {
+                job_info->status = res ? GCJobStatus::COMPLETED : GCJobStatus::FAILED;
+                // Resume accepting new requests for this pg
+                repl_dev->resume_accepting_reqs();
+            });
+    } else if (pg_id_param && !pg_id_param.value().empty()) {
+        // trigger gc for all chunks in a specific pg
+        const auto pg_id = std::stoul(pg_id_param.value());
+        LOGINFO("Received trigger_gc request for pg_id {}", pg_id);
+        auto hs_pg = const_cast< HSHomeObject::HS_PG* >(ho_.get_hs_pg(pg_id));
+        if (!hs_pg) {
+            nlohmann::json error;
+            error["pg_id"] = pg_id;
+            error["error"] = "PG not found";
+            response.send(Pistache::Http::Code::Not_Found, error.dump());
+            return;
+        }
+
+        nlohmann::json result;
+        const auto job_id = generate_job_id();
+        result["pg_id"] = pg_id;
+        result["job_id"] = job_id;
+        result["message"] = "GC triggered for a single pg, pls query job status using gc_job_status API";
+        // return response before starting the GC so that we don't block the client.
+        response.send(Pistache::Http::Code::Accepted, result.dump());
+
+        auto job_info = std::make_shared< GCJobInfo >(job_id, pg_id);
+        {
+            std::lock_guard lock(gc_job_mutex_);
+            gc_jobs_map_.set(job_id, job_info);
+        }
+
+        LOGINFO("GC job {} stopping GC scan timer", job_id);
+        gc_mgr->stop_gc_scan_timer();
+
+        // we block here until all gc tasks for the pg are done
+        trigger_gc_for_pg(pg_id, job_id);
+
+        LOGINFO("GC job {} restarting GC scan timer", job_id);
+        gc_mgr->start_gc_scan_timer();
+    } else {
+        LOGINFO("Received trigger_gc request for all chunks");
+        nlohmann::json result;
+        const auto job_id = generate_job_id();
+        result["job_id"] = job_id;
+        result["message"] = "GC triggered for all chunks, pls query job status using gc_job_status API";
+        // return response before starting the GC so that we don't block the client.
+        response.send(Pistache::Http::Code::Accepted, result.dump());
+
+        auto job_info = std::make_shared< GCJobInfo >(job_id);
+        {
+            std::lock_guard lock(gc_job_mutex_);
+            gc_jobs_map_.set(job_id, job_info);
+        }
+
+        std::vector< pg_id_t > pg_ids;
+        ho_.get_pg_ids(pg_ids);
+        LOGINFO("GC job {} will process {} PGs", job_id, pg_ids.size());
+        LOGINFO("GC job {} stopping GC scan timer", job_id);
+        gc_mgr->stop_gc_scan_timer();
+
+        // we block here until all gc tasks for the pg are done
+        for (const auto& pg_id : pg_ids) {
+            trigger_gc_for_pg(pg_id, job_id);
+        }
+
+        LOGINFO("GC job {} restarting GC scan timer", job_id);
+        gc_mgr->start_gc_scan_timer();
+    }
+}
+
+std::string HttpManager::generate_job_id() {
+    auto counter = job_counter_.fetch_add(1, std::memory_order_relaxed);
+    return fmt::format("trigger-gc-task-{}", counter);
+}
+
+void HttpManager::get_job_status(const std::string& job_id, nlohmann::json& result) {
+    result["job_id"] = job_id;
+    std::shared_ptr< GCJobInfo > job_info;
+    {
+        std::shared_lock lock(gc_job_mutex_);
+        job_info = gc_jobs_map_.get(job_id);
+    }
+
+    if (!job_info) {
+        result["error"] = "job_id not found, or job has been evicted";
+        return;
+    }
+
+    switch (job_info->status) {
+    case GCJobStatus::RUNNING:
+        result["status"] = "running";
+        break;
+    case GCJobStatus::COMPLETED:
+        result["status"] = "completed";
+        break;
+    case GCJobStatus::FAILED:
+        result["status"] = "failed";
+        break;
+    }
+
+    if (job_info->chunk_id.has_value()) { result["chunk_id"] = job_info->chunk_id.value(); }
+    if (job_info->pg_id.has_value()) { result["pg_id"] = job_info->pg_id.value(); }
+
+    if (job_info->total_chunks > 0) {
+        nlohmann::json stats;
+        stats["total_chunks"] = job_info->total_chunks;
+        stats["success_count"] = job_info->success_count;
+        stats["failed_count"] = job_info->failed_count;
+        result["statistics"] = stats;
+    }
+}
+
+void HttpManager::get_gc_job_status(const Pistache::Rest::Request& request, Pistache::Http::ResponseWriter response) {
+    auto job_id_param = request.query().get("job_id");
+    if (job_id_param && !job_id_param.value().empty()) {
+        const auto job_id = job_id_param.value();
+        LOGINFO("query job {} status!", job_id);
+        nlohmann::json result;
+        get_job_status(job_id, result);
+        response.send(Pistache::Http::Code::Ok, result.dump());
+        return;
+    }
+
+    LOGINFO("query all job status!");
+    nlohmann::json result;
+    std::vector< std::string > job_ids;
+    {
+        std::shared_lock lock(gc_job_mutex_);
+        for (const auto& [k, v] : gc_jobs_map_) {
+            job_ids.push_back(k);
+        }
+    }
+
+    for (const auto& job_id : job_ids) {
+        nlohmann::json job_json;
+        get_job_status(job_id, job_json);
+        result["jobs"].push_back(job_json);
+    }
+
+    response.send(Pistache::Http::Code::Ok, result.dump());
+}
+
+void HttpManager::trigger_gc_for_pg(uint16_t pg_id, const std::string& job_id) {
+    auto hs_pg = const_cast< HSHomeObject::HS_PG* >(ho_.get_hs_pg(pg_id));
+    RELEASE_ASSERT(hs_pg, "HS PG {} not found during GC job {}", pg_id, job_id);
+
+    LOGINFO("GC job {} draining pending GC tasks for PG {}", job_id, pg_id);
+    auto gc_mgr = ho_.gc_manager();
+    gc_mgr->drain_pg_pending_gc_task(pg_id);
+    auto pg_sb = hs_pg->pg_sb_.get();
+    std::vector< homestore::chunk_num_t > pg_chunks(pg_sb->get_chunk_ids(), pg_sb->get_chunk_ids() + pg_sb->num_chunks);
+
+    LOGINFO("GC job {} processing PG {} with {} chunks", job_id, pg_id, pg_chunks.size());
+    hs_pg->repl_dev_->quiesce_reqs();
+    std::vector< folly::SemiFuture< bool > > gc_task_futures;
+
+    std::shared_ptr< GCJobInfo > job_info;
+    {
+        std::shared_lock lock(gc_job_mutex_);
+        job_info = gc_jobs_map_.get(job_id);
+    }
+
+    auto chunk_selector = ho_.chunk_selector();
+
+    for (const auto& chunk_id : pg_chunks) {
+        job_info->total_chunks++;
+        // Determine priority based on chunk state (INUSE means has open shard)
+        auto chunk = chunk_selector->get_extend_vchunk(chunk_id);
+        RELEASE_ASSERT(chunk, "Chunk {} not found during GC job {}", chunk_id, job_id);
+        auto priority = chunk->m_state == ChunkState::INUSE ? task_priority::emergent : task_priority::normal;
+
+        // Clear in-memory requests only for emergent priority chunks (chunks with open shards)
+        if (priority == task_priority::emergent) { hs_pg->repl_dev_->clear_chunk_req(chunk_id); }
+
+        // Submit GC task for this chunk
+        auto future = gc_mgr->submit_gc_task(priority, chunk_id);
+        gc_task_futures.push_back(std::move(future));
+        LOGDEBUG("GC job {} for chunk {} in PG {} with priority={}", job_id, chunk_id, pg_id,
+                 (priority == task_priority::emergent) ? "emergent" : "normal");
+    }
+
+    folly::collectAllUnsafe(gc_task_futures)
+        .thenValue([job_info](auto&& results) {
+            for (auto const& ok : results) {
+                RELEASE_ASSERT(ok.hasValue(), "we never throw any exception when copying data");
+                if (ok.value()) {
+                    job_info->success_count++;
+                } else {
+                    job_info->failed_count++;
+                }
+            }
+        })
+        .thenValue([this, pg_id, job_info, gc_mgr](auto&& rets) {
+            LOGINFO("All GC tasks have been processed");
+            const auto& job_id = job_info->job_id;
+
+            auto hs_pg = const_cast< HSHomeObject::HS_PG* >(ho_.get_hs_pg(pg_id));
+            RELEASE_ASSERT(hs_pg, "HS PG {} not found during GC job {}", pg_id, job_id);
+            // Resume accepting new requests for this pg
+            hs_pg->repl_dev_->resume_accepting_reqs();
+            LOGINFO("GC job {} resumed accepting requests for PG {}", job_id, pg_id);
+
+            job_info->status = job_info->failed_count ? GCJobStatus::FAILED : GCJobStatus::COMPLETED;
+            LOGINFO("GC job {} completed: total={}, success={}, failed={}", job_id, job_info->total_chunks,
+                    job_info->success_count, job_info->failed_count);
+        })
+        .get();
+}
+
 #ifdef _PRERELEASE
 void HttpManager::crash_system(const Pistache::Rest::Request& request, Pistache::Http::ResponseWriter response) {
     std::string crash_type;