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A stack of space map tweaks.

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new_block() is now a concrete method implemented using the virtual
find_free() and inc() methods.

recursive space map is better at giving correct reference counts.
This commit is contained in:
Joe Thornber
2013-04-23 10:57:47 +01:00
parent e0230c5c55
commit d8a208cbc8
7 changed files with 107 additions and 104 deletions
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68
persistent-data/space-maps/careful_alloc.cc
View File

@ -17,16 +17,12 @@
// <http://www.gnu.org/licenses/>.
#include "persistent-data/space-maps/careful_alloc.h"
#include <set>
#include "persistent-data/space-maps/subtracting_span_iterator.h"
//----------------------------------------------------------------
namespace {
class sm_careful_alloc : public checked_space_map {
private:
typedef set<block_address> block_set;
public:
typedef shared_ptr<sm_careful_alloc> ptr;
@ -72,63 +68,9 @@ namespace {
mark_freed(b);
}
// FIXME: rewrite with tests using the run_list stuff.
class no_freed_blocks_iterator : public span_iterator {
public:
no_freed_blocks_iterator(span_iterator &sub_it,
block_set const &freed_blocks)
: sub_it_(sub_it),
freed_blocks_(freed_blocks) {
}
virtual maybe_span first() {
current_span_ = sub_it_.first();
if (current_span_)
current_begin_ = current_span_->first;
return next();
}
virtual maybe_span next() {
if (!current_span_)
return current_span_;
if (current_begin_ == current_span_->second) {
current_span_ = sub_it_.next();
if (!current_span_)
return current_span_;
current_begin_ = current_span_->first;
}
// FIXME: slow
while (current_begin_ != current_span_->second &&
freed_blocks_.count(current_begin_))
current_begin_++;
block_address b = current_begin_;
// FIXME: factor out common code
while (current_begin_ != current_span_->second &&
!freed_blocks_.count(current_begin_))
current_begin_++;
block_address e = current_begin_;
return maybe_span(span(b, e));
}
private:
span_iterator &sub_it_;
block_set const &freed_blocks_;
maybe_span current_span_;
block_address current_begin_;
};
virtual maybe_block new_block(span_iterator &it) {
no_freed_blocks_iterator filtered_it(it, freed_blocks_);
return sm_->new_block(filtered_it);
virtual maybe_block find_free(span_iterator &it) {
subtracting_span_iterator filtered_it(it, freed_blocks_);
return sm_->find_free(filtered_it);
}
virtual bool count_possibly_greater_than_one(block_address b) const {
@ -173,7 +115,7 @@ namespace {
}
checked_space_map::ptr sm_;
block_set freed_blocks_;
subtracting_span_iterator::block_set freed_blocks_;
};
}

7
persistent-data/space-maps/core.h
View File

@ -72,17 +72,14 @@ namespace persistent_data {
nr_free_++;
}
maybe_block new_block(span_iterator &it) {
maybe_block find_free(span_iterator &it) {
for (maybe_span ms = it.first(); ms; ms = it.next()) {
for (block_address b = ms->first; b < ms->second; b++) {
if (b >= counts_.size())
throw std::runtime_error("block out of bounds");
if (!counts_[b]) {
counts_[b] = 1;
nr_free_--;
if (!counts_[b])
return maybe_block(b);
}
}
}

13
persistent-data/space-maps/disk.cc
View File

@ -150,13 +150,9 @@ namespace {
}
boost::optional<unsigned> find_free(unsigned begin, unsigned end) {
for (unsigned i = max(begin, ie_.none_free_before_); i < end; i++) {
if (lookup(i) == 0) {
insert(i, 1);
ie_.none_free_before_ = i + 1;
for (unsigned i = max(begin, ie_.none_free_before_); i < end; i++)
if (lookup(i) == 0)
return boost::optional<unsigned>(i);
}
}
return boost::optional<unsigned>();
}
@ -311,7 +307,7 @@ namespace {
// FIXME: keep track of the lowest free block so we
// can start searching from a suitable place.
maybe_block new_block(span_iterator &it) {
maybe_block find_free(span_iterator &it) {
for (maybe_span ms = it.first(); ms; ms = it.next()) {
block_address begin = ms->first;
block_address end = ms->second;
@ -328,10 +324,7 @@ namespace {
optional<unsigned> maybe_b = bm.find_free(bit_begin, bit_end);
if (maybe_b) {
indexes_->save_ie(index, bm.get_ie());
nr_allocated_++;
block_address b = (index * ENTRIES_PER_BLOCK) + *maybe_b;
assert(get_count(b) == 1);
return b;
}
}

91
persistent-data/space-maps/recursive.cc
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@ -17,6 +17,7 @@
// <http://www.gnu.org/licenses/>.
#include "persistent-data/space-maps/recursive.h"
#include "persistent-data/space-maps/subtracting_span_iterator.h"
using namespace persistent_data;
@ -54,7 +55,8 @@ namespace {
public:
sm_recursive(checked_space_map::ptr sm)
: sm_(sm),
depth_(0) {
depth_(0),
flush_in_progress_(false) {
}
virtual block_address get_nr_blocks() const {
@ -66,9 +68,29 @@ namespace {
}
virtual ref_t get_count(block_address b) const {
cant_recurse("get_count");
recursing_const_lock lock(*this);
return sm_->get_count(b);
ref_t count = sm_->get_count(b);
op_map::const_iterator ops_it = ops_.find(b);
if (ops_it != ops_.end()) {
list<block_op>::const_iterator it, end = ops_it->second.end();
for (it = ops_it->second.begin(); it != end; ++it) {
switch (it->op_) {
case block_op::INC:
count++;
break;
case block_op::DEC:
count--;
break;
case block_op::SET:
count = it->b_;
break;
}
}
}
return count;
}
virtual void set_count(block_address b, ref_t c) {
@ -104,20 +126,44 @@ namespace {
}
virtual maybe_block
new_block(span_iterator &it) {
cant_recurse("new_block()");
find_free(span_iterator &it) {
recursing_lock lock(*this);
return sm_->new_block(it);
subtracting_span_iterator filtered_it(it, allocated_blocks_);
return sm_->find_free(filtered_it);
}
virtual bool count_possibly_greater_than_one(block_address b) const {
if (depth_)
return true;
recursing_const_lock lock(*this);
bool gto = sm_->count_possibly_greater_than_one(b);
if (!gto) {
ref_t count = 1;
else {
recursing_const_lock lock(*this);
return sm_->count_possibly_greater_than_one(b);
// FIXME: duplication
op_map::const_iterator ops_it = ops_.find(b);
if (ops_it != ops_.end()) {
list<block_op>::const_iterator it, end = ops_it->second.end();
for (it = ops_it->second.begin(); it != end; ++it) {
switch (it->op_) {
case block_op::INC:
count++;
break;
case block_op::DEC:
count--;
break;
case block_op::SET:
count = it->b_;
break;
}
}
}
gto = count > 1;
}
return gto;
}
virtual void extend(block_address extra_blocks) {
@ -153,12 +199,23 @@ namespace {
}
void flush_ops() {
if (flush_in_progress_)
return;
flush_in_progress_ = true;
flush_ops_();
flush_in_progress_ = false;
}
private:
void flush_ops_() {
op_map::const_iterator it, end = ops_.end();
for (it = ops_.begin(); it != end; ++it) {
recursing_lock lock(*this);
list<block_op> const &ops = it->second;
list<block_op>::const_iterator op_it, op_end = ops.end();
for (op_it = ops.begin(); op_it != op_end; ++op_it) {
recursing_lock lock(*this);
switch (op_it->op_) {
case block_op::INC:
sm_->inc(op_it->b_);
@ -176,11 +233,14 @@ namespace {
}
ops_.clear();
allocated_blocks_.clear();
}
private:
void add_op(block_op const &op) {
ops_[op.b_].push_back(op);
if (op.op_ == block_op::INC || (op.op_ == block_op::SET && op.rc_ > 0))
allocated_blocks_.insert(op.b_);
}
void cant_recurse(string const &method) const {
@ -228,6 +288,9 @@ namespace {
typedef map<block_address, list<block_op> > op_map;
op_map ops_;
subtracting_span_iterator::block_set allocated_blocks_;
bool flush_in_progress_;
};
}

3
persistent-data/space-maps/subtracting_span_iterator.h
View File

@ -71,7 +71,8 @@ namespace persistent_data {
void get_current_span_from_sub_it() {
current_span_ = sub_it_.next();
current_begin_ = current_span_->first;
if (current_span_)
current_begin_ = current_span_->first;
}
maybe_span next_() {