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// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
#include "common/debug.h"
#include "common/errno.h"
#include "SimplePolicy.h"
#define dout_context g_ceph_context
#define dout_subsys ceph_subsys_rbd_mirror
#undef dout_prefix
#define dout_prefix *_dout << "rbd::mirror::image_map::SimplePolicy: " << this \
<< " " << __func__ << ": "
namespace rbd {
namespace mirror {
namespace image_map {
SimplePolicy::SimplePolicy(librados::IoCtx &ioctx)
: Policy(ioctx) {
}
size_t SimplePolicy::calc_images_per_instance(const InstanceToImageMap& map,
size_t image_count) {
size_t nr_instances = 0;
for (auto const &it : map) {
if (!Policy::is_dead_instance(it.first)) {
++nr_instances;
}
}
ceph_assert(nr_instances > 0);
size_t images_per_instance = image_count / nr_instances;
if (images_per_instance == 0) {
++images_per_instance;
}
return images_per_instance;
}
void SimplePolicy::do_shuffle_add_instances(
const InstanceToImageMap& map, size_t image_count,
std::set<std::string> *remap_global_image_ids) {
uint64_t images_per_instance = calc_images_per_instance(map, image_count);
dout(5) << "images per instance=" << images_per_instance << dendl;
for (auto const &instance : map) {
if (instance.second.size() <= images_per_instance) {
continue;
}
auto it = instance.second.begin();
uint64_t cut_off = instance.second.size() - images_per_instance;
while (it != instance.second.end() && cut_off > 0) {
if (Policy::is_image_shuffling(*it)) {
--cut_off;
} else if (Policy::can_shuffle_image(*it)) {
--cut_off;
remap_global_image_ids->emplace(*it);
}
++it;
}
}
}
std::string SimplePolicy::do_map(const InstanceToImageMap& map,
const std::string &global_image_id) {
auto min_it = map.end();
for (auto it = map.begin(); it != map.end(); ++it) {
ceph_assert(it->second.find(global_image_id) == it->second.end());
if (Policy::is_dead_instance(it->first)) {
continue;
} else if (min_it == map.end()) {
min_it = it;
} else if (it->second.size() < min_it->second.size()) {
min_it = it;
}
}
ceph_assert(min_it != map.end());
dout(20) << "global_image_id=" << global_image_id << " maps to instance_id="
<< min_it->first << dendl;
return min_it->first;
}
} // namespace image_map
} // namespace mirror
} // namespace rbd
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