ceph/src/os/fs/aio.h

   1 // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
   2 // vim: ts=8 sw=2 smarttab
   3
   4 #pragma once
   5
   6 #include "acconfig.h"
   7 #ifdef HAVE_LIBAIO
   8 # include <libaio.h>
   9
  10 #include <boost/intrusive/list.hpp>
  11 #include <boost/container/small_vector.hpp>
  12
  13 #include "include/buffer.h"
  14
  15 struct aio_t {
  16   struct iocb iocb;  // must be first element; see shenanigans in aio_queue_t
  17   void *priv;
  18   int fd;
  19   boost::container::small_vector<iovec,4> iov;
  20   uint64_t offset, length;
  21   int rval;
  22   bufferlist bl;  ///< write payload (so that it remains stable for duration)
  23
  24   boost::intrusive::list_member_hook<> queue_item;
  25
  26   aio_t(void *p, int f) : priv(p), fd(f), offset(0), length(0), rval(-1000) {
  27   }
  28
  29   void pwritev(uint64_t _offset, uint64_t len) {
  30     offset = _offset;
  31     length = len;
  32     io_prep_pwritev(&iocb, fd, &iov[0], iov.size(), offset);
  33   }
  34   void pread(uint64_t _offset, uint64_t len) {
  35     offset = _offset;
  36     length = len;
  37     bufferptr p = buffer::create_page_aligned(length);
  38     io_prep_pread(&iocb, fd, p.c_str(), length, offset);
  39     bl.append(std::move(p));
  40   }
  41
  42   int get_return_value() {
  43     return rval;
  44   }
  45 };
  46
  47 typedef boost::intrusive::list<
  48   aio_t,
  49   boost::intrusive::member_hook<
  50     aio_t,
  51     boost::intrusive::list_member_hook<>,
  52     &aio_t::queue_item> > aio_list_t;
  53
  54 struct aio_queue_t {
  55   int max_iodepth;
  56   io_context_t ctx;
  57
  58   explicit aio_queue_t(unsigned max_iodepth)
  59     : max_iodepth(max_iodepth),
  60       ctx(0) {
  61   }
  62   ~aio_queue_t() {
  63     assert(ctx == 0);
  64   }
  65
  66   int init() {
  67     assert(ctx == 0);
  68     int r = io_setup(max_iodepth, &ctx);
  69     if (r < 0) {
  70       if (ctx) {
  71         io_destroy(ctx);
  72         ctx = 0;
  73       }
  74     }
  75     return r;
  76   }
  77   void shutdown() {
  78     if (ctx) {
  79       int r = io_destroy(ctx);
  80       assert(r == 0);
  81       ctx = 0;
  82     }
  83   }
  84
  85   int submit(aio_t &aio, int *retries);
  86   int get_next_completed(int timeout_ms, aio_t **paio, int max);
  87 };
  88
  89 #endif