Merging r4130, r4131, r4135: Linux AIO related fixes: *) Fixing Linux AIO syscalls return value handling: syscall(2) uses usual libc convention, it returns -1 on error and sets errno. Obsolete _syscall(2) returns negative value of error. *) Fixing Linux AIO initiatialization: AIO operations are disabled if kernel does not support them. Previously worker just exited. *) The "worker_aio_requests" directive. The default value is 32 AIO simultaneous requests per worker. Previously they were hardcoded to 1024, and it was too large, since Linux allocated them early on io_setup(), but not on request itself. So with default value of /proc/sys/fs/aio-max-nr equal to 65536 only 64 worker processes could be run simultaneously. 32 AIO requests are enough for modern disks even if server runs only 1 worker.

/*
 * Copyright (C) Igor Sysoev
 */


#include <ngx_config.h>
#include <ngx_core.h>


ngx_uint_t  ngx_pagesize;
ngx_uint_t  ngx_pagesize_shift;
ngx_uint_t  ngx_cacheline_size;


void *ngx_alloc(size_t size, ngx_log_t *log)
{
    void  *p;

    p = malloc(size);
    if (p == NULL) {
        ngx_log_error(NGX_LOG_EMERG, log, ngx_errno,
                      "malloc(%uz) failed", size);
    }

    ngx_log_debug2(NGX_LOG_DEBUG_ALLOC, log, 0, "malloc: %p:%uz", p, size);

    return p;
}


void *ngx_calloc(size_t size, ngx_log_t *log)
{
    void  *p;

    p = ngx_alloc(size, log);

    if (p) {
        ngx_memzero(p, size);
    }

    return p;
}