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src/os/unix/ngx_linux_aio_read.c - nginx source code

Functions defined

Source code


  2. /*
  3. * Copyright (C) Igor Sysoev
  4. * Copyright (C) Nginx, Inc.
  5. */


  8. #include <ngx_config.h>
  9. #include <ngx_core.h>
  10. #include <ngx_event.h>


  13. extern int            ngx_eventfd;
  14. extern aio_context_t  ngx_aio_ctx;


  17. static void ngx_file_aio_event_handler(ngx_event_t *ev);


  20. static int
  21. ‌io_submit(aio_context_t ctx, long n, struct iocb **paiocb)
  22. {
  23.     return syscall(SYS_io_submit, ctx, n, paiocb);
  24. }


  27. ngx_int_t
  28. ‌ngx_file_aio_init(ngx_file_t *file, ngx_pool_t *pool)
  29. {
  30.     ngx_event_aio_t  *aio;

  32.     aio = ngx_pcalloc(pool, sizeof(ngx_event_aio_t));
  33.     if (aio == NULL) {
  34.         return NGX_ERROR;
  35.     }

  37.     aio->file = file;
  38.     aio->fd = file->fd;
  39.     aio->event.data = aio;
  40.     aio->event.ready = 1;
  41.     aio->event.log = file->log;

  43.     file->aio = aio;

  45.     return NGX_OK;
  46. }


  49. ssize_t
  50. ‌ngx_file_aio_read(ngx_file_t *file, u_char *buf, size_t size, off_t offset,
  51.     ngx_pool_t *pool)
  52. {
  53.     ngx_err_t         err;
  54.     struct iocb      *piocb[1];
  55.     ngx_event_t      *ev;
  56.     ngx_event_aio_t  *aio;

  58.     if (!ngx_file_aio) {
  59.         return ngx_read_file(file, buf, size, offset);
  60.     }

  62.     if (file->aio == NULL && ngx_file_aio_init(file, pool) != NGX_OK) {
  63.         return NGX_ERROR;
  64.     }

  66.     aio = file->aio;
  67.     ev = &aio->event;

  69.     if (!ev->ready) {
  70.         ngx_log_error(NGX_LOG_ALERT, file->log, 0,
  71.                       "second aio post for \"%V\"", &file->name);
  72.         return NGX_AGAIN;
  73.     }

  75.     ngx_log_debug4(NGX_LOG_DEBUG_CORE, file->log, 0,
  76.                    "aio complete:%d @%O:%uz %V",
  77.                    ev->complete, offset, size, &file->name);

  79.     if (ev->complete) {
  80.         ev->active = 0;
  81.         ev->complete = 0;

  83.         if (aio->res >= 0) {
  84.             ngx_set_errno(0);
  85.             return aio->res;
  86.         }

  88.         ngx_set_errno(-aio->res);

  90.         ngx_log_error(NGX_LOG_CRIT, file->log, ngx_errno,
  91.                       "aio read \"%s\" failed", file->name.data);

  93.         return NGX_ERROR;
  94.     }

  96.     ngx_memzero(&aio->aiocb, sizeof(struct iocb));

  98.     aio->aiocb.aio_data = (uint64_t) (uintptr_t) ev;
  99.     aio->aiocb.aio_lio_opcode = IOCB_CMD_PREAD;
  100.     aio->aiocb.aio_fildes = file->fd;
  101.     aio->aiocb.aio_buf = (uint64_t) (uintptr_t) buf;
  102.     aio->aiocb.aio_nbytes = size;
  103.     aio->aiocb.aio_offset = offset;
  104.     aio->aiocb.aio_flags = IOCB_FLAG_RESFD;
  105.     aio->aiocb.aio_resfd = ngx_eventfd;

  107.     ev->handler = ngx_file_aio_event_handler;

  109.     piocb[0] = &aio->aiocb;

  111.     if (io_submit(ngx_aio_ctx, 1, piocb) == 1) {
  112.         ev->active = 1;
  113.         ev->ready = 0;
  114.         ev->complete = 0;

  116.         return NGX_AGAIN;
  117.     }

  119.     err = ngx_errno;

  121.     if (err == NGX_EAGAIN) {
  122.         return ngx_read_file(file, buf, size, offset);
  123.     }

  125.     ngx_log_error(NGX_LOG_CRIT, file->log, err,
  126.                   "io_submit(\"%V\") failed", &file->name);

  128.     if (err == NGX_ENOSYS) {
  129.         ngx_file_aio = 0;
  130.         return ngx_read_file(file, buf, size, offset);
  131.     }

  133.     return NGX_ERROR;
  134. }


  137. static void
  138. ‌ngx_file_aio_event_handler(ngx_event_t *ev)
  139. {
  140.     ngx_event_aio_t  *aio;

  142.     aio = ev->data;

  144.     ngx_log_debug2(NGX_LOG_DEBUG_CORE, ev->log, 0,
  145.                    "aio event handler fd:%d %V", aio->fd, &aio->file->name);

  147.     aio->handler(ev);
  148. }

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