Add Redis source code for testing

1 files changed, 445 insertions, 0 deletions

diff --git a/examples/redis-unstable/src/bio.c b/examples/redis-unstable/src/bio.c
new file mode 100644
index 0000000..4d36e3e
--- /dev/null
+++ b/examples/redis-unstable/src/bio.c
@@ -0,0 +1,445 @@
+/* Background I/O service for Redis.
+ *
+ * This file implements operations that we need to perform in the background.
+ * Currently there are 3 operations:
+ * 1) a background close(2) system call. This is needed when the process is
+ *    the last owner of a reference to a file closing it means unlinking it, and
+ *    the deletion of the file is slow, blocking the server.
+ * 2) AOF fsync
+ * 3) lazyfree of memory
+ *
+ * In the future we'll either continue implementing new things we need or
+ * we'll switch to libeio. However there are probably long term uses for this
+ * file as we may want to put Redis specific background tasks here.
+ *
+ * DESIGN
+ * ------
+ *
+ * The design is simple: We have a structure representing a job to perform,
+ * and several worker threads and job queues. Every job type is assigned to
+ * a specific worker thread, and a single worker may handle several different
+ * job types.
+ * Every thread waits for new jobs in its queue, and processes every job
+ * sequentially.
+ *
+ * Jobs handled by the same worker are guaranteed to be processed from the
+ * least-recently-inserted to the most-recently-inserted (older jobs processed
+ * first).
+ *
+ * To let the creator of the job to be notified about the completion of the 
+ * operation, it will need to submit additional dummy job, coined as
+ * completion job request that will be written back eventually, by the
+ * background thread, into completion job response queue. This notification
+ * layout can simplify flows that might submit more than one job, such as
+ * in case of FLUSHALL which for a single command submits multiple jobs. It
+ * is also correct because jobs are processed in FIFO fashion.
+ *
+ * ----------------------------------------------------------------------------
+ *
+ * Copyright (c) 2009-Present, Redis Ltd.
+ * All rights reserved.
+ *
+ * Licensed under your choice of (a) the Redis Source Available License 2.0
+ * (RSALv2); or (b) the Server Side Public License v1 (SSPLv1); or (c) the
+ * GNU Affero General Public License v3 (AGPLv3).
+ */
+
+#include "server.h"
+#include "bio.h"
+#include <fcntl.h>
+
+static char* bio_worker_title[] = {
+    "bio_close_file",
+    "bio_aof",
+    "bio_lazy_free",
+};
+
+#define BIO_WORKER_NUM (sizeof(bio_worker_title) / sizeof(*bio_worker_title))
+
+static unsigned int bio_job_to_worker[] = {
+    [BIO_CLOSE_FILE] = 0,
+    [BIO_AOF_FSYNC] = 1,
+    [BIO_CLOSE_AOF] = 1,
+    [BIO_LAZY_FREE] = 2,
+    [BIO_COMP_RQ_CLOSE_FILE] = 0,
+    [BIO_COMP_RQ_AOF_FSYNC]  = 1,
+    [BIO_COMP_RQ_LAZY_FREE]  = 2
+};
+
+static pthread_t bio_threads[BIO_WORKER_NUM];
+static pthread_mutex_t bio_mutex[BIO_WORKER_NUM];
+static pthread_cond_t bio_newjob_cond[BIO_WORKER_NUM];
+static list *bio_jobs[BIO_WORKER_NUM];
+static unsigned long bio_jobs_counter[BIO_NUM_OPS] = {0};
+
+/* The bio_comp_list is used to hold completion job responses and to handover
+ * to main thread to callback as notification for job completion. Main
+ * thread will be triggered to read the list by signaling via writing to a pipe */
+static list *bio_comp_list;
+static pthread_mutex_t bio_mutex_comp;
+static int job_comp_pipe[2];   /* Pipe used to awake the event loop */
+
+typedef struct bio_comp_item {
+    comp_fn *func;    /* callback after completion job will be processed  */
+    uint64_t arg;     /* user data to be passed to the function */
+    void *ptr;        /* user pointer to be passed to the function */
+} bio_comp_item;
+
+/* This structure represents a background Job. It is only used locally to this
+ * file as the API does not expose the internals at all. */
+typedef union bio_job {
+    struct {
+        int type; /* Job-type tag. This needs to appear as the first element in all union members. */
+    } header;
+
+    /* Job specific arguments.*/
+    struct {
+        int type;
+        int fd; /* Fd for file based background jobs */
+        long long offset; /* A job-specific offset, if applicable */
+        unsigned need_fsync:1; /* A flag to indicate that a fsync is required before
+                                * the file is closed. */
+        unsigned need_reclaim_cache:1; /* A flag to indicate that reclaim cache is required before
+                                * the file is closed. */
+    } fd_args;
+
+    struct {
+        int type;
+        lazy_free_fn *free_fn; /* Function that will free the provided arguments */
+        void *free_args[]; /* List of arguments to be passed to the free function */
+    } free_args;
+    struct {
+        int type; /* header */
+        comp_fn *fn; /* callback. Handover to main thread to cb as notify for job completion */
+        uint64_t arg; /* callback arguments */
+        void *ptr; /* callback pointer */
+    } comp_rq;
+} bio_job;
+
+void *bioProcessBackgroundJobs(void *arg);
+void bioPipeReadJobCompList(aeEventLoop *el, int fd, void *privdata, int mask);
+
+/* Make sure we have enough stack to perform all the things we do in the
+ * main thread. */
+#define REDIS_THREAD_STACK_SIZE (1024*1024*4)
+
+/* Initialize the background system, spawning the thread. */
+void bioInit(void) {
+    pthread_attr_t attr;
+    pthread_t thread;
+    size_t stacksize;
+    unsigned long j;
+
+    /* Initialization of state vars and objects */
+    for (j = 0; j < BIO_WORKER_NUM; j++) {
+        pthread_mutex_init(&bio_mutex[j],NULL);
+        pthread_cond_init(&bio_newjob_cond[j],NULL);
+        bio_jobs[j] = listCreate();
+    }
+
+    /* init jobs comp responses */
+    bio_comp_list = listCreate();
+    pthread_mutex_init(&bio_mutex_comp, NULL);
+
+    /* Create a pipe for background thread to be able to wake up the redis main thread.
+     * Make the pipe non blocking. This is just a best effort aware mechanism
+     * and we do not want to block not in the read nor in the write half.
+     * Enable close-on-exec flag on pipes in case of the fork-exec system calls in
+     * sentinels or redis servers. */
+    if (anetPipe(job_comp_pipe, O_CLOEXEC|O_NONBLOCK, O_CLOEXEC|O_NONBLOCK) == -1) {
+        serverLog(LL_WARNING,
+                  "Can't create the pipe for bio thread: %s", strerror(errno));
+        exit(1);
+    }
+
+    /* Register a readable event for the pipe used to awake the event loop on job completion */
+    if (aeCreateFileEvent(server.el, job_comp_pipe[0], AE_READABLE,
+                          bioPipeReadJobCompList, NULL) == AE_ERR) {
+        serverPanic("Error registering the readable event for the bio pipe.");
+    }
+
+    /* Set the stack size as by default it may be small in some system */
+    pthread_attr_init(&attr);
+    pthread_attr_getstacksize(&attr,&stacksize);
+    if (!stacksize) stacksize = 1; /* The world is full of Solaris Fixes */
+    while (stacksize < REDIS_THREAD_STACK_SIZE) stacksize *= 2;
+    pthread_attr_setstacksize(&attr, stacksize);
+
+    /* Ready to spawn our threads. We use the single argument the thread
+     * function accepts in order to pass the job ID the thread is
+     * responsible for. */
+    for (j = 0; j < BIO_WORKER_NUM; j++) {
+        int err = pthread_create(&thread,&attr,bioProcessBackgroundJobs, (void*) j);
+        if (err) {
+            serverLog(LL_WARNING, "Fatal: Can't initialize Background Jobs. Error message: %s", strerror(err));
+            exit(1);
+        }
+        bio_threads[j] = thread;
+    }
+}
+
+void bioSubmitJob(int type, bio_job *job) {
+    job->header.type = type;
+    unsigned long worker = bio_job_to_worker[type];
+    pthread_mutex_lock(&bio_mutex[worker]);
+    listAddNodeTail(bio_jobs[worker],job);
+    bio_jobs_counter[type]++;
+    pthread_cond_signal(&bio_newjob_cond[worker]);
+    pthread_mutex_unlock(&bio_mutex[worker]);
+}
+
+void bioCreateLazyFreeJob(lazy_free_fn free_fn, int arg_count, ...) {
+    va_list valist;
+    /* Allocate memory for the job structure and all required
+     * arguments */
+    bio_job *job = zmalloc(sizeof(*job) + sizeof(void *) * (arg_count));
+    job->free_args.free_fn = free_fn;
+
+    va_start(valist, arg_count);
+    for (int i = 0; i < arg_count; i++) {
+        job->free_args.free_args[i] = va_arg(valist, void *);
+    }
+    va_end(valist);
+    bioSubmitJob(BIO_LAZY_FREE, job);
+}
+
+void bioCreateCompRq(bio_worker_t assigned_worker, comp_fn *func, uint64_t user_data, void *user_ptr) {
+    int type;
+    switch (assigned_worker) {
+        case BIO_WORKER_CLOSE_FILE:
+            type = BIO_COMP_RQ_CLOSE_FILE;
+            break;
+        case BIO_WORKER_AOF_FSYNC:
+            type = BIO_COMP_RQ_AOF_FSYNC;
+            break;
+        case BIO_WORKER_LAZY_FREE:
+            type = BIO_COMP_RQ_LAZY_FREE;
+            break;
+        default:
+            serverPanic("Invalid worker type in bioCreateCompRq().");
+    }
+
+    bio_job *job = zmalloc(sizeof(*job));
+    job->comp_rq.fn = func;
+    job->comp_rq.arg = user_data;
+    job->comp_rq.ptr = user_ptr;
+    bioSubmitJob(type, job);
+}
+
+void bioCreateCloseJob(int fd, int need_fsync, int need_reclaim_cache) {
+    bio_job *job = zmalloc(sizeof(*job));
+    job->fd_args.fd = fd;
+    job->fd_args.need_fsync = need_fsync;
+    job->fd_args.need_reclaim_cache = need_reclaim_cache;
+
+    bioSubmitJob(BIO_CLOSE_FILE, job);
+}
+
+void bioCreateCloseAofJob(int fd, long long offset, int need_reclaim_cache) {
+    bio_job *job = zmalloc(sizeof(*job));
+    job->fd_args.fd = fd;
+    job->fd_args.offset = offset;
+    job->fd_args.need_fsync = 1;
+    job->fd_args.need_reclaim_cache = need_reclaim_cache;
+
+    bioSubmitJob(BIO_CLOSE_AOF, job);
+}
+
+void bioCreateFsyncJob(int fd, long long offset, int need_reclaim_cache) {
+    bio_job *job = zmalloc(sizeof(*job));
+    job->fd_args.fd = fd;
+    job->fd_args.offset = offset;
+    job->fd_args.need_reclaim_cache = need_reclaim_cache;
+
+    bioSubmitJob(BIO_AOF_FSYNC, job);
+}
+
+void *bioProcessBackgroundJobs(void *arg) {
+    bio_job *job;
+    unsigned long worker = (unsigned long) arg;
+    sigset_t sigset;
+
+    /* Check that the worker is within the right interval. */
+    serverAssert(worker < BIO_WORKER_NUM);
+
+    redis_set_thread_title(bio_worker_title[worker]);
+
+    redisSetCpuAffinity(server.bio_cpulist);
+
+    makeThreadKillable();
+
+    pthread_mutex_lock(&bio_mutex[worker]);
+    /* Block SIGALRM so we are sure that only the main thread will
+     * receive the watchdog signal. */
+    sigemptyset(&sigset);
+    sigaddset(&sigset, SIGALRM);
+    int err = pthread_sigmask(SIG_BLOCK, &sigset, NULL);
+    if (err)
+        serverLog(LL_WARNING,
+            "Warning: can't mask SIGALRM in bio.c thread: %s", strerror(err));
+
+    while(1) {
+        listNode *ln;
+
+        /* The loop always starts with the lock hold. */
+        if (listLength(bio_jobs[worker]) == 0) {
+            pthread_cond_wait(&bio_newjob_cond[worker], &bio_mutex[worker]);
+            continue;
+        }
+        /* Get the job from the queue. */
+        ln = listFirst(bio_jobs[worker]);
+        job = ln->value;
+        /* It is now possible to unlock the background system as we know have
+         * a stand alone job structure to process.*/
+        pthread_mutex_unlock(&bio_mutex[worker]);
+
+        /* Process the job accordingly to its type. */
+        int job_type = job->header.type;
+
+        if (job_type == BIO_CLOSE_FILE) {
+            if (job->fd_args.need_fsync &&
+                redis_fsync(job->fd_args.fd) == -1 &&
+                errno != EBADF && errno != EINVAL)
+            {
+                serverLog(LL_WARNING, "Fail to fsync the AOF file: %s",strerror(errno));
+            }
+            if (job->fd_args.need_reclaim_cache) {
+                if (reclaimFilePageCache(job->fd_args.fd, 0, 0) == -1) {
+                    serverLog(LL_NOTICE,"Unable to reclaim page cache: %s", strerror(errno));
+                }
+            }
+            close(job->fd_args.fd);
+        } else if (job_type == BIO_AOF_FSYNC || job_type == BIO_CLOSE_AOF) {
+            /* The fd may be closed by main thread and reused for another
+             * socket, pipe, or file. We just ignore these errno because
+             * aof fsync did not really fail. */
+            if (redis_fsync(job->fd_args.fd) == -1 &&
+                errno != EBADF && errno != EINVAL)
+            {
+                int last_status;
+                atomicGet(server.aof_bio_fsync_status,last_status);
+                atomicSet(server.aof_bio_fsync_status,C_ERR);
+                atomicSet(server.aof_bio_fsync_errno,errno);
+                if (last_status == C_OK) {
+                    serverLog(LL_WARNING,
+                        "Fail to fsync the AOF file: %s",strerror(errno));
+                }
+            } else {
+                atomicSet(server.aof_bio_fsync_status,C_OK);
+                atomicSet(server.fsynced_reploff_pending, job->fd_args.offset);
+            }
+
+            if (job->fd_args.need_reclaim_cache) {
+                if (reclaimFilePageCache(job->fd_args.fd, 0, 0) == -1) {
+                    serverLog(LL_NOTICE,"Unable to reclaim page cache: %s", strerror(errno));
+                }
+            }
+            if (job_type == BIO_CLOSE_AOF)
+                close(job->fd_args.fd);
+        } else if (job_type == BIO_LAZY_FREE) {
+            job->free_args.free_fn(job->free_args.free_args);
+        } else if ((job_type == BIO_COMP_RQ_CLOSE_FILE) ||
+                   (job_type == BIO_COMP_RQ_AOF_FSYNC) ||
+                   (job_type == BIO_COMP_RQ_LAZY_FREE)) {
+            bio_comp_item *comp_rsp = zmalloc(sizeof(bio_comp_item));
+            comp_rsp->func = job->comp_rq.fn;
+            comp_rsp->arg = job->comp_rq.arg;
+            comp_rsp->ptr = job->comp_rq.ptr;
+
+            /* just write it to completion job responses */
+            pthread_mutex_lock(&bio_mutex_comp);
+            listAddNodeTail(bio_comp_list, comp_rsp);
+            pthread_mutex_unlock(&bio_mutex_comp);
+
+            if (write(job_comp_pipe[1],"A",1) != 1) {
+                /* Pipe is non-blocking, write() may fail if it's full. */
+            }
+        } else {
+            serverPanic("Wrong job type in bioProcessBackgroundJobs().");
+        }
+        zfree(job);
+
+        /* Lock again before reiterating the loop, if there are no longer
+         * jobs to process we'll block again in pthread_cond_wait(). */
+        pthread_mutex_lock(&bio_mutex[worker]);
+        listDelNode(bio_jobs[worker], ln);
+        bio_jobs_counter[job_type]--;
+        pthread_cond_signal(&bio_newjob_cond[worker]);
+    }
+}
+
+/* Return the number of pending jobs of the specified type. */
+unsigned long bioPendingJobsOfType(int type) {
+    unsigned int worker = bio_job_to_worker[type];
+
+    pthread_mutex_lock(&bio_mutex[worker]);
+    unsigned long val = bio_jobs_counter[type];
+    pthread_mutex_unlock(&bio_mutex[worker]);
+
+    return val;
+}
+
+/* Wait for the job queue of the worker for jobs of specified type to become empty. */
+void bioDrainWorker(int job_type) {
+    unsigned long worker = bio_job_to_worker[job_type];
+
+    pthread_mutex_lock(&bio_mutex[worker]);
+    while (listLength(bio_jobs[worker]) > 0) {
+        pthread_cond_wait(&bio_newjob_cond[worker], &bio_mutex[worker]);
+    }
+    pthread_mutex_unlock(&bio_mutex[worker]);
+}
+
+/* Kill the running bio threads in an unclean way. This function should be
+ * used only when it's critical to stop the threads for some reason.
+ * Currently Redis does this only on crash (for instance on SIGSEGV) in order
+ * to perform a fast memory check without other threads messing with memory. */
+void bioKillThreads(void) {
+    int err;
+    unsigned long j;
+
+    for (j = 0; j < BIO_WORKER_NUM; j++) {
+        if (bio_threads[j] == pthread_self()) continue;
+        if (bio_threads[j] && pthread_cancel(bio_threads[j]) == 0) {
+            if ((err = pthread_join(bio_threads[j],NULL)) != 0) {
+                serverLog(LL_WARNING,
+                    "Bio worker thread #%lu can not be joined: %s",
+                        j, strerror(err));
+            } else {
+                serverLog(LL_WARNING,
+                    "Bio worker thread #%lu terminated",j);
+            }
+        }
+    }
+}
+
+void bioPipeReadJobCompList(aeEventLoop *el, int fd, void *privdata, int mask) {
+    UNUSED(el);
+    UNUSED(mask);
+    UNUSED(privdata);
+
+    char buf[128];
+    list *tmp_list = NULL;
+
+    while (read(fd, buf, sizeof(buf)) == sizeof(buf));
+
+    /* Handle event loop events if pipe was written from event loop API */
+    pthread_mutex_lock(&bio_mutex_comp);
+    if (listLength(bio_comp_list)) {
+        tmp_list = bio_comp_list;
+        bio_comp_list = listCreate();
+    }
+    pthread_mutex_unlock(&bio_mutex_comp);
+
+    if (!tmp_list) return;
+
+    /* callback to all job completions  */
+    while (listLength(tmp_list)) {
+        listNode *ln = listFirst(tmp_list);
+        bio_comp_item *rsp = ln->value;
+        listDelNode(tmp_list, ln);
+        rsp->func(rsp->arg, rsp->ptr);
+        zfree(rsp);
+    }
+    listRelease(tmp_list);
+}