From e6918187568dbd01842d8d1d2c808ce16a894239 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 21 Apr 2024 13:54:28 +0200 Subject: Adding upstream version 18.2.2. Signed-off-by: Daniel Baumann --- src/zstd/lib/common/pool.c | 344 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 344 insertions(+) create mode 100644 src/zstd/lib/common/pool.c (limited to 'src/zstd/lib/common/pool.c') diff --git a/src/zstd/lib/common/pool.c b/src/zstd/lib/common/pool.c new file mode 100644 index 000000000..aa4b4de0d --- /dev/null +++ b/src/zstd/lib/common/pool.c @@ -0,0 +1,344 @@ +/* + * Copyright (c) 2016-2020, Yann Collet, Facebook, Inc. + * All rights reserved. + * + * This source code is licensed under both the BSD-style license (found in the + * LICENSE file in the root directory of this source tree) and the GPLv2 (found + * in the COPYING file in the root directory of this source tree). + * You may select, at your option, one of the above-listed licenses. + */ + + +/* ====== Dependencies ======= */ +#include /* size_t */ +#include "debug.h" /* assert */ +#include "zstd_internal.h" /* ZSTD_malloc, ZSTD_free */ +#include "pool.h" + +/* ====== Compiler specifics ====== */ +#if defined(_MSC_VER) +# pragma warning(disable : 4204) /* disable: C4204: non-constant aggregate initializer */ +#endif + + +#ifdef ZSTD_MULTITHREAD + +#include "threading.h" /* pthread adaptation */ + +/* A job is a function and an opaque argument */ +typedef struct POOL_job_s { + POOL_function function; + void *opaque; +} POOL_job; + +struct POOL_ctx_s { + ZSTD_customMem customMem; + /* Keep track of the threads */ + ZSTD_pthread_t* threads; + size_t threadCapacity; + size_t threadLimit; + + /* The queue is a circular buffer */ + POOL_job *queue; + size_t queueHead; + size_t queueTail; + size_t queueSize; + + /* The number of threads working on jobs */ + size_t numThreadsBusy; + /* Indicates if the queue is empty */ + int queueEmpty; + + /* The mutex protects the queue */ + ZSTD_pthread_mutex_t queueMutex; + /* Condition variable for pushers to wait on when the queue is full */ + ZSTD_pthread_cond_t queuePushCond; + /* Condition variables for poppers to wait on when the queue is empty */ + ZSTD_pthread_cond_t queuePopCond; + /* Indicates if the queue is shutting down */ + int shutdown; +}; + +/* POOL_thread() : + * Work thread for the thread pool. + * Waits for jobs and executes them. + * @returns : NULL on failure else non-null. + */ +static void* POOL_thread(void* opaque) { + POOL_ctx* const ctx = (POOL_ctx*)opaque; + if (!ctx) { return NULL; } + for (;;) { + /* Lock the mutex and wait for a non-empty queue or until shutdown */ + ZSTD_pthread_mutex_lock(&ctx->queueMutex); + + while ( ctx->queueEmpty + || (ctx->numThreadsBusy >= ctx->threadLimit) ) { + if (ctx->shutdown) { + /* even if !queueEmpty, (possible if numThreadsBusy >= threadLimit), + * a few threads will be shutdown while !queueEmpty, + * but enough threads will remain active to finish the queue */ + ZSTD_pthread_mutex_unlock(&ctx->queueMutex); + return opaque; + } + ZSTD_pthread_cond_wait(&ctx->queuePopCond, &ctx->queueMutex); + } + /* Pop a job off the queue */ + { POOL_job const job = ctx->queue[ctx->queueHead]; + ctx->queueHead = (ctx->queueHead + 1) % ctx->queueSize; + ctx->numThreadsBusy++; + ctx->queueEmpty = ctx->queueHead == ctx->queueTail; + /* Unlock the mutex, signal a pusher, and run the job */ + ZSTD_pthread_cond_signal(&ctx->queuePushCond); + ZSTD_pthread_mutex_unlock(&ctx->queueMutex); + + job.function(job.opaque); + + /* If the intended queue size was 0, signal after finishing job */ + ZSTD_pthread_mutex_lock(&ctx->queueMutex); + ctx->numThreadsBusy--; + if (ctx->queueSize == 1) { + ZSTD_pthread_cond_signal(&ctx->queuePushCond); + } + ZSTD_pthread_mutex_unlock(&ctx->queueMutex); + } + } /* for (;;) */ + assert(0); /* Unreachable */ +} + +POOL_ctx* POOL_create(size_t numThreads, size_t queueSize) { + return POOL_create_advanced(numThreads, queueSize, ZSTD_defaultCMem); +} + +POOL_ctx* POOL_create_advanced(size_t numThreads, size_t queueSize, + ZSTD_customMem customMem) { + POOL_ctx* ctx; + /* Check parameters */ + if (!numThreads) { return NULL; } + /* Allocate the context and zero initialize */ + ctx = (POOL_ctx*)ZSTD_calloc(sizeof(POOL_ctx), customMem); + if (!ctx) { return NULL; } + /* Initialize the job queue. + * It needs one extra space since one space is wasted to differentiate + * empty and full queues. + */ + ctx->queueSize = queueSize + 1; + ctx->queue = (POOL_job*)ZSTD_malloc(ctx->queueSize * sizeof(POOL_job), customMem); + ctx->queueHead = 0; + ctx->queueTail = 0; + ctx->numThreadsBusy = 0; + ctx->queueEmpty = 1; + { + int error = 0; + error |= ZSTD_pthread_mutex_init(&ctx->queueMutex, NULL); + error |= ZSTD_pthread_cond_init(&ctx->queuePushCond, NULL); + error |= ZSTD_pthread_cond_init(&ctx->queuePopCond, NULL); + if (error) { POOL_free(ctx); return NULL; } + } + ctx->shutdown = 0; + /* Allocate space for the thread handles */ + ctx->threads = (ZSTD_pthread_t*)ZSTD_malloc(numThreads * sizeof(ZSTD_pthread_t), customMem); + ctx->threadCapacity = 0; + ctx->customMem = customMem; + /* Check for errors */ + if (!ctx->threads || !ctx->queue) { POOL_free(ctx); return NULL; } + /* Initialize the threads */ + { size_t i; + for (i = 0; i < numThreads; ++i) { + if (ZSTD_pthread_create(&ctx->threads[i], NULL, &POOL_thread, ctx)) { + ctx->threadCapacity = i; + POOL_free(ctx); + return NULL; + } } + ctx->threadCapacity = numThreads; + ctx->threadLimit = numThreads; + } + return ctx; +} + +/*! POOL_join() : + Shutdown the queue, wake any sleeping threads, and join all of the threads. +*/ +static void POOL_join(POOL_ctx* ctx) { + /* Shut down the queue */ + ZSTD_pthread_mutex_lock(&ctx->queueMutex); + ctx->shutdown = 1; + ZSTD_pthread_mutex_unlock(&ctx->queueMutex); + /* Wake up sleeping threads */ + ZSTD_pthread_cond_broadcast(&ctx->queuePushCond); + ZSTD_pthread_cond_broadcast(&ctx->queuePopCond); + /* Join all of the threads */ + { size_t i; + for (i = 0; i < ctx->threadCapacity; ++i) { + ZSTD_pthread_join(ctx->threads[i], NULL); /* note : could fail */ + } } +} + +void POOL_free(POOL_ctx *ctx) { + if (!ctx) { return; } + POOL_join(ctx); + ZSTD_pthread_mutex_destroy(&ctx->queueMutex); + ZSTD_pthread_cond_destroy(&ctx->queuePushCond); + ZSTD_pthread_cond_destroy(&ctx->queuePopCond); + ZSTD_free(ctx->queue, ctx->customMem); + ZSTD_free(ctx->threads, ctx->customMem); + ZSTD_free(ctx, ctx->customMem); +} + + + +size_t POOL_sizeof(POOL_ctx *ctx) { + if (ctx==NULL) return 0; /* supports sizeof NULL */ + return sizeof(*ctx) + + ctx->queueSize * sizeof(POOL_job) + + ctx->threadCapacity * sizeof(ZSTD_pthread_t); +} + + +/* @return : 0 on success, 1 on error */ +static int POOL_resize_internal(POOL_ctx* ctx, size_t numThreads) +{ + if (numThreads <= ctx->threadCapacity) { + if (!numThreads) return 1; + ctx->threadLimit = numThreads; + return 0; + } + /* numThreads > threadCapacity */ + { ZSTD_pthread_t* const threadPool = (ZSTD_pthread_t*)ZSTD_malloc(numThreads * sizeof(ZSTD_pthread_t), ctx->customMem); + if (!threadPool) return 1; + /* replace existing thread pool */ + memcpy(threadPool, ctx->threads, ctx->threadCapacity * sizeof(*threadPool)); + ZSTD_free(ctx->threads, ctx->customMem); + ctx->threads = threadPool; + /* Initialize additional threads */ + { size_t threadId; + for (threadId = ctx->threadCapacity; threadId < numThreads; ++threadId) { + if (ZSTD_pthread_create(&threadPool[threadId], NULL, &POOL_thread, ctx)) { + ctx->threadCapacity = threadId; + return 1; + } } + } } + /* successfully expanded */ + ctx->threadCapacity = numThreads; + ctx->threadLimit = numThreads; + return 0; +} + +/* @return : 0 on success, 1 on error */ +int POOL_resize(POOL_ctx* ctx, size_t numThreads) +{ + int result; + if (ctx==NULL) return 1; + ZSTD_pthread_mutex_lock(&ctx->queueMutex); + result = POOL_resize_internal(ctx, numThreads); + ZSTD_pthread_cond_broadcast(&ctx->queuePopCond); + ZSTD_pthread_mutex_unlock(&ctx->queueMutex); + return result; +} + +/** + * Returns 1 if the queue is full and 0 otherwise. + * + * When queueSize is 1 (pool was created with an intended queueSize of 0), + * then a queue is empty if there is a thread free _and_ no job is waiting. + */ +static int isQueueFull(POOL_ctx const* ctx) { + if (ctx->queueSize > 1) { + return ctx->queueHead == ((ctx->queueTail + 1) % ctx->queueSize); + } else { + return (ctx->numThreadsBusy == ctx->threadLimit) || + !ctx->queueEmpty; + } +} + + +static void POOL_add_internal(POOL_ctx* ctx, POOL_function function, void *opaque) +{ + POOL_job const job = {function, opaque}; + assert(ctx != NULL); + if (ctx->shutdown) return; + + ctx->queueEmpty = 0; + ctx->queue[ctx->queueTail] = job; + ctx->queueTail = (ctx->queueTail + 1) % ctx->queueSize; + ZSTD_pthread_cond_signal(&ctx->queuePopCond); +} + +void POOL_add(POOL_ctx* ctx, POOL_function function, void* opaque) +{ + assert(ctx != NULL); + ZSTD_pthread_mutex_lock(&ctx->queueMutex); + /* Wait until there is space in the queue for the new job */ + while (isQueueFull(ctx) && (!ctx->shutdown)) { + ZSTD_pthread_cond_wait(&ctx->queuePushCond, &ctx->queueMutex); + } + POOL_add_internal(ctx, function, opaque); + ZSTD_pthread_mutex_unlock(&ctx->queueMutex); +} + + +int POOL_tryAdd(POOL_ctx* ctx, POOL_function function, void* opaque) +{ + assert(ctx != NULL); + ZSTD_pthread_mutex_lock(&ctx->queueMutex); + if (isQueueFull(ctx)) { + ZSTD_pthread_mutex_unlock(&ctx->queueMutex); + return 0; + } + POOL_add_internal(ctx, function, opaque); + ZSTD_pthread_mutex_unlock(&ctx->queueMutex); + return 1; +} + + +#else /* ZSTD_MULTITHREAD not defined */ + +/* ========================== */ +/* No multi-threading support */ +/* ========================== */ + + +/* We don't need any data, but if it is empty, malloc() might return NULL. */ +struct POOL_ctx_s { + int dummy; +}; +static POOL_ctx g_ctx; + +POOL_ctx* POOL_create(size_t numThreads, size_t queueSize) { + return POOL_create_advanced(numThreads, queueSize, ZSTD_defaultCMem); +} + +POOL_ctx* POOL_create_advanced(size_t numThreads, size_t queueSize, ZSTD_customMem customMem) { + (void)numThreads; + (void)queueSize; + (void)customMem; + return &g_ctx; +} + +void POOL_free(POOL_ctx* ctx) { + assert(!ctx || ctx == &g_ctx); + (void)ctx; +} + +int POOL_resize(POOL_ctx* ctx, size_t numThreads) { + (void)ctx; (void)numThreads; + return 0; +} + +void POOL_add(POOL_ctx* ctx, POOL_function function, void* opaque) { + (void)ctx; + function(opaque); +} + +int POOL_tryAdd(POOL_ctx* ctx, POOL_function function, void* opaque) { + (void)ctx; + function(opaque); + return 1; +} + +size_t POOL_sizeof(POOL_ctx* ctx) { + if (ctx==NULL) return 0; /* supports sizeof NULL */ + assert(ctx == &g_ctx); + return sizeof(*ctx); +} + +#endif /* ZSTD_MULTITHREAD */ -- cgit v1.2.3