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A little optimisation for the core space map.

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This commit is contained in:
Joe Thornber 2013-05-09 14:09:47 +01:00
parent 8ecf2f27ed
commit 42a4221499
1 changed files with 16 additions and 4 deletions
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20
persistent-data/space-maps/core.h
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@ -30,7 +30,8 @@ namespace persistent_data {
core_map(block_address nr_blocks) core_map(block_address nr_blocks)
: counts_(nr_blocks, 0), : counts_(nr_blocks, 0),
nr_free_(nr_blocks) { nr_free_(nr_blocks),
search_start_(0ull) {
} }
block_address get_nr_blocks() const { block_address get_nr_blocks() const {
@ -49,8 +50,12 @@ namespace persistent_data {
if (counts_[b] == 0 && c > 0) if (counts_[b] == 0 && c > 0)
nr_free_--; nr_free_--;
else if (counts_[b] > 0 && c == 0) else if (counts_[b] > 0 && c == 0) {
if (b < search_start_)
search_start_ = b;
nr_free_++; nr_free_++;
}
counts_[b] = c; counts_[b] = c;
} }
@ -68,13 +73,19 @@ namespace persistent_data {
void dec(block_address b) { void dec(block_address b) {
counts_[b]--; counts_[b]--;
if (counts_[b] == 0) if (counts_[b] == 0) {
if (b < search_start_)
search_start_ = b;
nr_free_++; nr_free_++;
}
} }
maybe_block find_free(span_iterator &it) { maybe_block find_free(span_iterator &it) {
for (maybe_span ms = it.first(); ms; ms = it.next()) { for (maybe_span ms = it.first(); ms; ms = it.next()) {
for (block_address b = ms->first; b < ms->second; b++) { if (search_start_ >= ms->second)
continue;
for (block_address b = max(search_start_, ms->first); b < ms->second; b++) {
if (b >= counts_.size()) if (b >= counts_.size())
throw std::runtime_error("block out of bounds"); throw std::runtime_error("block out of bounds");
@ -111,6 +122,7 @@ namespace persistent_data {
private: private:
std::vector<ref_t> counts_; std::vector<ref_t> counts_;
unsigned nr_free_; unsigned nr_free_;
block_address search_start_;
}; };
} }