feat: Add fair unified memory pool

common/src/main/scala/org/apache/comet/CometConf.scala

@@ -504,8 +504,8 @@ object CometConf extends ShimCometConf {
     .doc(
       "The type of memory pool to be used for Comet native execution. " +
         "Available memory pool types are 'greedy', 'fair_spill', 'greedy_task_shared', " +
-        "'fair_spill_task_shared', 'greedy_global' and 'fair_spill_global', By default, " +
-        "this config is 'greedy_task_shared'.")
+        "'fair_spill_task_shared', 'greedy_global' and 'fair_spill_global'. For off-heap " +
+        "types are 'unified' and `fair_unified`.")
     .stringConf
     .createWithDefault("greedy_task_shared")
 

docs/source/user-guide/configs.md

@@ -48,7 +48,7 @@ Comet provides the following configuration settings.
 | spark.comet.exec.hashJoin.enabled | Whether to enable hashJoin by default. | true |
 | spark.comet.exec.initCap.enabled | Whether to enable initCap by default. | false |
 | spark.comet.exec.localLimit.enabled | Whether to enable localLimit by default. | true |
-| spark.comet.exec.memoryPool | The type of memory pool to be used for Comet native execution. Available memory pool types are 'greedy', 'fair_spill', 'greedy_task_shared', 'fair_spill_task_shared', 'greedy_global' and 'fair_spill_global', By default, this config is 'greedy_task_shared'. | greedy_task_shared |
+| spark.comet.exec.memoryPool | The type of memory pool to be used for Comet native execution. Available memory pool types are 'greedy', 'fair_spill', 'greedy_task_shared', 'fair_spill_task_shared', 'greedy_global' and 'fair_spill_global'. For off-heap types are 'unified' and `fair_unified`. | greedy_task_shared |
 | spark.comet.exec.project.enabled | Whether to enable project by default. | true |
 | spark.comet.exec.replaceSortMergeJoin | Experimental feature to force Spark to replace SortMergeJoin with ShuffledHashJoin for improved performance. This feature is not stable yet. For more information, refer to the Comet Tuning Guide (https://datafusion.apache.org/comet/user-guide/tuning.html). | false |
 | spark.comet.exec.shuffle.compression.codec | The codec of Comet native shuffle used to compress shuffle data. lz4, zstd, and snappy are supported. Compression can be disabled by setting spark.shuffle.compress=false. | lz4 |

native/core/Cargo.toml

@@ -77,6 +77,7 @@ datafusion-comet-proto = { workspace = true }
 object_store = { workspace = true }
 url = { workspace = true }
 chrono = { workspace = true }
+parking_lot = "0.12.3"
 
 [dev-dependencies]
 pprof = { version = "0.14.0", features = ["flamegraph"] }

native/core/src/execution/fair_memory_pool.rs

@@ -0,0 +1,166 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+use std::{
+    fmt::{Debug, Formatter, Result as FmtResult},
+    sync::Arc,
+};
+
+use jni::objects::GlobalRef;
+
+use crate::{
+    errors::CometResult,
+    jvm_bridge::{jni_call, JVMClasses},
+};
+use datafusion::{
+    common::DataFusionError,
+    execution::memory_pool::{MemoryPool, MemoryReservation},
+};
+use datafusion_common::resources_err;
+use datafusion_execution::memory_pool::MemoryConsumer;
+use parking_lot::Mutex;
+
+/// A DataFusion fair `MemoryPool` implementation for Comet. Internally this is
+/// implemented via delegating calls to [`crate::jvm_bridge::CometTaskMemoryManager`].
+pub struct CometFairMemoryPool {
+    task_memory_manager_handle: Arc<GlobalRef>,
+    pool_size: usize,
+    state: Mutex<CometFairPoolState>,
+}
+
+struct CometFairPoolState {
+    used: usize,
+    num: usize,
+}
+
+impl Debug for CometFairMemoryPool {
+    fn fmt(&self, f: &mut Formatter<'_>) -> FmtResult {
+        let state = self.state.lock();
+        f.debug_struct("CometFairMemoryPool")
+            .field("pool_size", &self.pool_size)
+            .field("used", &state.used)
+            .field("num", &state.num)
+            .finish()
+    }
+}
+
+impl CometFairMemoryPool {
+    pub fn new(
+        task_memory_manager_handle: Arc<GlobalRef>,
+        pool_size: usize,
+    ) -> CometFairMemoryPool {
+        Self {
+            task_memory_manager_handle,
+            pool_size,
+            state: Mutex::new(CometFairPoolState { used: 0, num: 0 }),
+        }
+    }
+
+    fn acquire(&self, additional: usize) -> CometResult<i64> {
+        let mut env = JVMClasses::get_env()?;
+        let handle = self.task_memory_manager_handle.as_obj();
+        unsafe {
+            jni_call!(&mut env,
+              comet_task_memory_manager(handle).acquire_memory(additional as i64) -> i64)
+        }
+    }
+
+    fn release(&self, size: usize) -> CometResult<()> {
+        let mut env = JVMClasses::get_env()?;
+        let handle = self.task_memory_manager_handle.as_obj();
+        unsafe {
+            jni_call!(&mut env, comet_task_memory_manager(handle).release_memory(size as i64) -> ())
+        }
+    }
+}
+
+unsafe impl Send for CometFairMemoryPool {}
+unsafe impl Sync for CometFairMemoryPool {}
+
+impl MemoryPool for CometFairMemoryPool {
+    fn register(&self, _: &MemoryConsumer) {
+        let mut state = self.state.lock();
+        state.num = state
+            .num
+            .checked_add(1)
+            .expect("unexpected amount of register happened");
+    }
+
+    fn unregister(&self, _: &MemoryConsumer) {
+        let mut state = self.state.lock();
+        state.num = state
+            .num
+            .checked_sub(1)
+            .expect("unexpected amount of unregister happened");
+    }
+
+    fn grow(&self, reservation: &MemoryReservation, additional: usize) {
+        self.try_grow(reservation, additional).unwrap();
+    }
+
+    fn shrink(&self, reservation: &MemoryReservation, subtractive: usize) {
+        if subtractive > 0 {
+            let mut state = self.state.lock();
+            let size = reservation.size();
+            if size < subtractive {
+                panic!("Failed to release {subtractive} bytes where only {size} bytes reserved")
+            }
+            self.release(subtractive)
+                .unwrap_or_else(|_| panic!("Failed to release {} bytes", subtractive));
+            state.used = state.used.checked_sub(subtractive).unwrap();
+        }
+    }
+
+    fn try_grow(
+        &self,
+        reservation: &MemoryReservation,
+        additional: usize,
+    ) -> Result<(), DataFusionError> {
+        if additional > 0 {
+            let mut state = self.state.lock();
+            let num = state.num;
+            let limit = self.pool_size.checked_div(num).unwrap();
+            let size = reservation.size();
+            if limit < size + additional {
+                return resources_err!(
+                    "Failed to acquire {additional} bytes where {size} bytes already reserved and the fair limit is {limit} bytes, {num} registered"
+                );
+            }
+
+            let acquired = self.acquire(additional)?;
+            // If the number of bytes we acquired is less than the requested, return an error,
+            // and hopefully will trigger spilling from the caller side.
+            if acquired < additional as i64 {
+                // Release the acquired bytes before throwing error
+                self.release(acquired as usize)?;
+
+                return resources_err!(
+                    "Failed to acquire {} bytes, only got {} bytes. Reserved: {} bytes",
+                    additional,
+                    acquired,
+                    state.used
+                );
+            }
+            state.used = state.used.checked_add(additional).unwrap();
+        }
+        Ok(())
+    }
+
+    fn reserved(&self) -> usize {
+        self.state.lock().used
+    }
+}

native/core/src/execution/jni_api.rs

@@ -63,6 +63,7 @@ use std::num::NonZeroUsize;
 use std::sync::Mutex;
 use tokio::runtime::Runtime;
 
+use crate::execution::fair_memory_pool::CometFairMemoryPool;
 use crate::execution::operators::ScanExec;
 use crate::execution::shuffle::{read_ipc_compressed, CompressionCodec};
 use crate::execution::spark_plan::SparkPlan;
@@ -108,6 +109,7 @@ struct ExecutionContext {
 #[derive(PartialEq, Eq)]
 enum MemoryPoolType {
     Unified,
+    FairUnified,
     Greedy,
     FairSpill,
     GreedyTaskShared,
@@ -285,11 +287,14 @@ fn parse_memory_pool_config(
     memory_limit: i64,
     memory_limit_per_task: i64,
 ) -> CometResult<MemoryPoolConfig> {
+    let pool_size = memory_limit as usize;
     let memory_pool_config = if use_unified_memory_manager {
-        MemoryPoolConfig::new(MemoryPoolType::Unified, 0)
+        match memory_pool_type.as_str() {
+            "fair_unified" => MemoryPoolConfig::new(MemoryPoolType::FairUnified, pool_size),
+            _ => MemoryPoolConfig::new(MemoryPoolType::Unified, 0),
+        }
     } else {
         // Use the memory pool from DF
-        let pool_size = memory_limit as usize;
         let pool_size_per_task = memory_limit_per_task as usize;
         match memory_pool_type.as_str() {
             "fair_spill_task_shared" => {
@@ -327,6 +332,12 @@ fn create_memory_pool(
             let memory_pool = CometMemoryPool::new(comet_task_memory_manager);
             Arc::new(memory_pool)
         }
+        MemoryPoolType::FairUnified => {
+            // Set Comet fair memory pool for native
+            let memory_pool =
+                CometFairMemoryPool::new(comet_task_memory_manager, memory_pool_config.pool_size);
+            Arc::new(memory_pool)
+        }
         MemoryPoolType::Greedy => Arc::new(TrackConsumersPool::new(
             GreedyMemoryPool::new(memory_pool_config.pool_size),
             NonZeroUsize::new(NUM_TRACKED_CONSUMERS).unwrap(),

native/core/src/execution/mod.rs

@@ -29,6 +29,7 @@ pub(crate) mod util;
 pub use datafusion_comet_spark_expr::timezone;
 pub(crate) mod utils;
 
+mod fair_memory_pool;
 mod memory_pool;
 pub use memory_pool::*;
 

spark/src/test/scala/org/apache/spark/sql/CometTPCHQuerySuite.scala

@@ -94,6 +94,7 @@ class CometTPCHQuerySuite extends QueryTest with TPCBase with ShimCometTPCHQuery
     conf.set(CometConf.COMET_SHUFFLE_MODE.key, "jvm")
     conf.set(MEMORY_OFFHEAP_ENABLED.key, "true")
     conf.set(MEMORY_OFFHEAP_SIZE.key, "2g")
+    conf.set(CometConf.COMET_MEMORY_OVERHEAD.key, "2g")
   }
 
   protected override def createSparkSession: TestSparkSession = {