1 files changed, 0 insertions, 354 deletions
diff --git a/examples/redis-unstable/src/syscheck.c b/examples/redis-unstable/src/syscheck.c
deleted file mode 100644
index 1251c1d..0000000
--- a/examples/redis-unstable/src/syscheck.c
+++ /dev/null
@@ -1,354 +0,0 @@
-/*
- * Copyright (c) 2016-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 "fmacros.h"
-#include "config.h"
-#include "syscheck.h"
-#include "sds.h"
-#include "anet.h"
-
-#include <time.h>
-#include <sys/resource.h>
-#include <unistd.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <errno.h>
-#include <sys/wait.h>
-
-#ifdef __linux__
-#include <sys/mman.h>
-#endif
-
-
-#ifdef __linux__
-static sds read_sysfs_line(char *path) {
-    char buf[256];
-    FILE *f = fopen(path, "r");
-    if (!f) return NULL;
-    if (!fgets(buf, sizeof(buf), f)) {
-        fclose(f);
-        return NULL;
-    }
-    fclose(f);
-    sds res = sdsnew(buf);
-    res = sdstrim(res, " \n");
-    return res;
-}
-
-/* Verify our clocksource implementation doesn't go through a system call (uses vdso).
- * Going through a system call to check the time degrades Redis performance. */
-static int checkClocksource(sds *error_msg) {
-    unsigned long test_time_us, system_hz;
-    struct timespec ts;
-    unsigned long long start_us;
-    struct rusage ru_start, ru_end;
-
-    system_hz = sysconf(_SC_CLK_TCK);
-
-    if (getrusage(RUSAGE_SELF, &ru_start) != 0)
-        return 0;
-    if (clock_gettime(CLOCK_MONOTONIC, &ts) < 0) {
-        return 0;
-    }
-    start_us = (ts.tv_sec * 1000000 + ts.tv_nsec / 1000);
-
-    /* clock_gettime() busy loop of 5 times system tick (for a system_hz of 100 this is 50ms)
-     * Using system_hz is required to ensure accurate measurements from getrusage().
-     * If our clocksource is configured correctly (vdso) this will result in no system calls.
-     * If our clocksource is inefficient it'll waste most of the busy loop in the kernel. */
-    test_time_us = 5 * 1000000 / system_hz;
-    while (1) {
-        unsigned long long d;
-        if (clock_gettime(CLOCK_MONOTONIC, &ts) < 0)
-            return 0;
-        d = (ts.tv_sec * 1000000 + ts.tv_nsec / 1000) - start_us;
-        if (d >= test_time_us) break;
-    }
-    if (getrusage(RUSAGE_SELF, &ru_end) != 0)
-        return 0;
-
-    long long stime_us = (ru_end.ru_stime.tv_sec * 1000000 + ru_end.ru_stime.tv_usec) - (ru_start.ru_stime.tv_sec * 1000000 + ru_start.ru_stime.tv_usec);
-    long long utime_us = (ru_end.ru_utime.tv_sec * 1000000 + ru_end.ru_utime.tv_usec) - (ru_start.ru_utime.tv_sec * 1000000 + ru_start.ru_utime.tv_usec);
-
-    /* If more than 10% of the process time was in system calls we probably have an inefficient clocksource, print a warning */
-    if (stime_us * 10 > stime_us + utime_us) {
-        sds avail = read_sysfs_line("/sys/devices/system/clocksource/clocksource0/available_clocksource");
-        sds curr = read_sysfs_line("/sys/devices/system/clocksource/clocksource0/current_clocksource");
-        *error_msg = sdscatprintf(sdsempty(),
-           "Slow system clocksource detected. This can result in degraded performance. "
-           "Consider changing the system's clocksource. "
-           "Current clocksource: %s. Available clocksources: %s. "
-           "For example: run the command 'echo tsc > /sys/devices/system/clocksource/clocksource0/current_clocksource' as root. "
-           "To permanently change the system's clocksource you'll need to set the 'clocksource=' kernel command line parameter.",
-           curr ? curr : "", avail ? avail : "");
-        sdsfree(avail);
-        sdsfree(curr);
-        return -1;
-    } else {
-        return 1;
-    }
-}
-
-/* Verify we're not using the `xen` clocksource. The xen hypervisor's default clocksource is slow and affects
- * Redis's performance. This has been measured on ec2 xen based instances. ec2 recommends using the non-default
- * tsc clock source for these instances. */
-int checkXenClocksource(sds *error_msg) {
-    sds curr = read_sysfs_line("/sys/devices/system/clocksource/clocksource0/current_clocksource");
-    int res = 1;
-    if (curr == NULL) {
-        res = 0;
-    } else if (strcmp(curr, "xen") == 0) {
-        *error_msg = sdsnew(
-            "Your system is configured to use the 'xen' clocksource which might lead to degraded performance. "
-            "Check the result of the [slow-clocksource] system check: run 'redis-server --check-system' to check if "
-            "the system's clocksource isn't degrading performance.");
-        res = -1;
-    }
-    sdsfree(curr);
-    return res;
-}
-
-/* Verify overcommit is enabled.
- * When overcommit memory is disabled Linux will kill the forked child of a background save
- * if we don't have enough free memory to satisfy double the current memory usage even though
- * the forked child uses copy-on-write to reduce its actual memory usage. */
-int checkOvercommit(sds *error_msg) {
-    FILE *fp = fopen("/proc/sys/vm/overcommit_memory","r");
-    char buf[64];
-
-    if (!fp) return 0;
-    if (fgets(buf,64,fp) == NULL) {
-        fclose(fp);
-        return 0;
-    }
-    fclose(fp);
-
-    if (strtol(buf, NULL, 10) != 1) {
-        *error_msg = sdsnew(
-            "Memory overcommit must be enabled! Without it, a background save or replication may fail under low memory condition. "
-#if defined(USE_JEMALLOC)
-            "Being disabled, it can also cause failures without low memory condition, see https://github.com/jemalloc/jemalloc/issues/1328. "
-#endif
-            "To fix this issue add 'vm.overcommit_memory = 1' to /etc/sysctl.conf and then reboot or run the "
-            "command 'sysctl vm.overcommit_memory=1' for this to take effect.");
-        return -1;
-    } else {
-        return 1;
-    }
-}
-
-/* Make sure transparent huge pages aren't always enabled. When they are this can cause copy-on-write logic
- * to consume much more memory and reduce performance during forks. */
-int checkTHPEnabled(sds *error_msg) {
-    char buf[1024];
-
-    FILE *fp = fopen("/sys/kernel/mm/transparent_hugepage/enabled","r");
-    if (!fp) return 0;
-    if (fgets(buf,sizeof(buf),fp) == NULL) {
-        fclose(fp);
-        return 0;
-    }
-    fclose(fp);
-
-    if (strstr(buf,"[always]") != NULL) {
-        *error_msg = sdsnew(
-            "You have Transparent Huge Pages (THP) support enabled in your kernel. "
-            "This will create latency and memory usage issues with Redis. "
-            "To fix this issue run the command 'echo madvise > /sys/kernel/mm/transparent_hugepage/enabled' as root, "
-            "and add it to your /etc/rc.local in order to retain the setting after a reboot. "
-            "Redis must be restarted after THP is disabled (set to 'madvise' or 'never').");
-        return -1;
-    } else {
-        return 1;
-    }
-}
-
-#ifdef __arm64__
-/* Get size in kilobytes of the Shared_Dirty pages of the calling process for the
- * memory map corresponding to the provided address, or -1 on error. */
-static int smapsGetSharedDirty(unsigned long addr) {
-    int ret, in_mapping = 0, val = -1;
-    unsigned long from, to;
-    char buf[64];
-    FILE *f;
-
-    f = fopen("/proc/self/smaps", "r");
-    if (!f) return -1;
-
-    while (1) {
-        if (!fgets(buf, sizeof(buf), f))
-            break;
-
-        ret = sscanf(buf, "%lx-%lx", &from, &to);
-        if (ret == 2)
-            in_mapping = from <= addr && addr < to;
-
-        if (in_mapping && !memcmp(buf, "Shared_Dirty:", 13)) {
-            sscanf(buf, "%*s %d", &val);
-            /* If parsing fails, we remain with val == -1 */
-            break;
-        }
-    }
-
-    fclose(f);
-    return val;
-}
-
-/* Older arm64 Linux kernels have a bug that could lead to data corruption
- * during background save in certain scenarios. This function checks if the
- * kernel is affected.
- * The bug was fixed in commit ff1712f953e27f0b0718762ec17d0adb15c9fd0b
- * titled: "arm64: pgtable: Ensure dirty bit is preserved across pte_wrprotect()"
- */
-int checkLinuxMadvFreeForkBug(sds *error_msg) {
-    int ret, pipefd[2] = { -1, -1 };
-    pid_t pid;
-    char *p = NULL, *q;
-    int res = 1;
-    long page_size = sysconf(_SC_PAGESIZE);
-    long map_size = 3 * page_size;
-
-    /* Create a memory map that's in our full control (not one used by the allocator). */
-    p = mmap(NULL, map_size, PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
-    if (p == MAP_FAILED) {
-        return 0;
-    }
-
-    q = p + page_size;
-
-    /* Split the memory map in 3 pages by setting their protection as RO|RW|RO to prevent
-     * Linux from merging this memory map with adjacent VMAs. */
-    ret = mprotect(q, page_size, PROT_READ | PROT_WRITE);
-    if (ret < 0) {
-        res = 0;
-        goto exit;
-    }
-
-    /* Write to the page once to make it resident */
-    *(volatile char*)q = 0;
-
-    /* Tell the kernel that this page is free to be reclaimed. */
-#ifndef MADV_FREE
-#define MADV_FREE 8
-#endif
-    ret = madvise(q, page_size, MADV_FREE);
-    if (ret < 0) {
-        /* MADV_FREE is not available on older kernels that are presumably
-         * not affected. */
-        if (errno == EINVAL) goto exit;
-
-        res = 0;
-        goto exit;
-    }
-
-    /* Write to the page after being marked for freeing, this is supposed to take
-     * ownership of that page again. */
-    *(volatile char*)q = 0;
-
-    /* Create a pipe for the child to return the info to the parent. */
-    ret = anetPipe(pipefd, 0, 0);
-    if (ret < 0) {
-        res = 0;
-        goto exit;
-    }
-
-    /* Fork the process. */
-    pid = fork();
-    if (pid < 0) {
-        res = 0;
-        goto exit;
-    } else if (!pid) {
-        /* Child: check if the page is marked as dirty, page_size in kb.
-         * A value of 0 means the kernel is affected by the bug. */
-        ret = smapsGetSharedDirty((unsigned long) q);
-        if (!ret)
-            res = -1;
-        else if (ret == -1)     /* Failed to read */
-            res = 0;
-
-        ret = write(pipefd[1], &res, sizeof(res)); /* Assume success, ignore return value*/
-        exit(0);
-    } else {
-        /* Read the result from the child. */
-        ret = read(pipefd[0], &res, sizeof(res));
-        if (ret < 0) {
-            res = 0;
-        }
-
-        /* Reap the child pid. */
-        waitpid(pid, NULL, 0);
-    }
-
-exit:
-    /* Cleanup */
-    if (pipefd[0] != -1) close(pipefd[0]);
-    if (pipefd[1] != -1) close(pipefd[1]);
-    if (p != NULL) munmap(p, map_size);
-
-    if (res == -1)
-        *error_msg = sdsnew(
-            "Your kernel has a bug that could lead to data corruption during background save. "
-            "Please upgrade to the latest stable kernel.");
-
-    return res;
-}
-#endif /* __arm64__ */
-#endif /* __linux__ */
-
-/*
- * Standard system check interface:
- * Each check has a name `name` and a functions pointer `check_fn`.
- * `check_fn` should return:
- *   -1 in case the check fails.
- *   1 in case the check passes.
- *   0 in case the check could not be completed (usually because of some unexpected failed system call).
- *   When (and only when) the check fails and -1 is returned and error description is places in a new sds pointer to by
- *   the single `sds*` argument to `check_fn`. This message should be freed by the caller via `sdsfree()`.
- */
-typedef struct {
-    const char *name;
-    int (*check_fn)(sds*);
-} check;
-
-check checks[] = {
-#ifdef __linux__
-    {.name = "slow-clocksource", .check_fn = checkClocksource},
-    {.name = "xen-clocksource", .check_fn = checkXenClocksource},
-    {.name = "overcommit", .check_fn = checkOvercommit},
-    {.name = "THP", .check_fn = checkTHPEnabled},
-#ifdef __arm64__
-    {.name = "madvise-free-fork-bug", .check_fn = checkLinuxMadvFreeForkBug},
-#endif
-#endif
-    {.name = NULL, .check_fn = NULL}
-};
-
-/* Performs various system checks, returns 0 if any check fails, 1 otherwise. */
-int syscheck(void) {
-    check *cur_check = checks;
-    int ret = 1;
-    sds err_msg = NULL;
-    while (cur_check->check_fn) {
-        int res = cur_check->check_fn(&err_msg);
-        printf("[%s]...", cur_check->name);
-        if (res == 0) {
-            printf("skipped\n");
-        } else if (res == 1) {
-            printf("OK\n");
-        } else {
-            printf("WARNING:\n");
-            printf("%s\n", err_msg);
-            sdsfree(err_msg);
-            ret = 0;
-        }
-        cur_check++;
-    }
-
-    return ret;
-}