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This avoids some badness around some STL implementations #1337

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Merged
zwoop merged 1 commit into from
Jan 21, 2017
Merged

This avoids some badness around some STL implementations #1337

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19 changes: 14 additions & 5 deletions plugins/experimental/cache_promote/cache_promote.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -194,15 +194,17 @@ static LRUEntry NULL_LRU_ENTRY; // Used to create an "empty" new LRUEntry
class LRUPolicy : public PromotionPolicy
{
public:
LRUPolicy() : PromotionPolicy(), _buckets(1000), _hits(10), _lock(TSMutexCreate()) {}
LRUPolicy() : PromotionPolicy(), _buckets(1000), _hits(10), _lock(TSMutexCreate()), _list_size(0), _freelist_size(0) {}
~LRUPolicy()
{
TSDebug(PLUGIN_NAME, "deleting LRUPolicy object");
TSMutexLock(_lock);

_map.clear();
_list.clear();
_list_size = 0;
_freelist.clear();
_freelist_size = 0;

TSMutexUnlock(_lock);
TSMutexDestroy(_lock);
Expand Down Expand Up @@ -275,11 +277,13 @@ class LRUPolicy : public PromotionPolicy
map_it = _map.find(&hash);
if (_map.end() != map_it) {
// We have an entry in the LRU
TSAssert(_list.size() > 0); // mismatch in the LRUs hash and list, shouldn't happen
TSAssert(_list_size > 0); // mismatch in the LRUs hash and list, shouldn't happen
if (++(map_it->second->second) >= _hits) {
// Promoted! Cleanup the LRU, and signal success. Save the promoted entry on the freelist.
TSDebug(PLUGIN_NAME, "saving the LRUEntry to the freelist");
_freelist.splice(_freelist.begin(), _list, map_it->second);
++_freelist_size;
--_list_size;
_map.erase(map_it->first);
ret = true;
} else {
Expand All @@ -289,16 +293,19 @@ class LRUPolicy : public PromotionPolicy
}
} else {
// New LRU entry for the URL, try to repurpose the list entry as much as possible
if (_list.size() >= _buckets) {
if (_list_size >= _buckets) {
TSDebug(PLUGIN_NAME, "repurposing last LRUHash entry");
_list.splice(_list.begin(), _list, --_list.end());
_map.erase(&(_list.begin()->first));
} else if (_freelist.size() > 0) {
} else if (_freelist_size > 0) {
TSDebug(PLUGIN_NAME, "reusing LRUEntry from freelist");
_list.splice(_list.begin(), _freelist, _freelist.begin());
--_freelist_size;
++_list_size;
} else {
TSDebug(PLUGIN_NAME, "creating new LRUEntry");
_list.push_front(NULL_LRU_ENTRY);
++_list_size;
}
// Update the "new" LRUEntry and add it to the hash
_list.begin()->first = hash;
Expand Down Expand Up @@ -327,10 +334,12 @@ class LRUPolicy : public PromotionPolicy
private:
unsigned _buckets;
unsigned _hits;
// For the LRU
// For the LRU. Note that we keep track of the List sizes, because some versions fo STL have broken
// implementations of size(), making them obsessively slow on calling ::size().
TSMutex _lock;
LRUMap _map;
LRUList _list, _freelist;
size_t _list_size, _freelist_size;
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@SolidWallOfCode SolidWallOfCode Jan 18, 2017

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In eleventy, you can do

size_t _list_size = 0;
size_t _freelist_size = 0;

Just FYI, it's not important.

};

//////////////////////////////////////////////////////////////////////////////////////////////
Expand Down