{"id":1506,"date":"2011-11-30T19:44:53","date_gmt":"2011-11-30T08:44:53","guid":{"rendered":"http:\/\/blog.mozilla.org\/nnethercote\/?p=1506"},"modified":"2011-11-30T19:44:53","modified_gmt":"2011-11-30T08:44:53","slug":"memshrink-progress-report-week-24","status":"publish","type":"post","link":"https:\/\/blog.mozilla.org\/nnethercote\/2011\/11\/30\/memshrink-progress-report-week-24\/","title":{"rendered":"MemShrink progress report, week 24"},"content":{"rendered":"

Something that happened a while ago but I failed to notice was that Chris Leary added a regexp cache<\/a> which, among other things, is flushed on every GC.\u00a0 This fixed an existing problem where cold regexps were not being discarded<\/a>, which was a MemShrink:P1 bug because 10s or even 100s of MBs of compiled regexp code could accumulate in some circumstances.\u00a0 Nice work, Chris!<\/p>\n

Andrew McCreight fixed two leaks (here<\/a> and here<\/a>) involving WeakMaps.\u00a0 WeakMaps are an EcmaScript 5 feature and so are not used that much at the moment, but their popularity will increase over time.<\/p>\n

I landed some memory reporter infrastructure changes<\/a>.\u00a0 These will make it much easier to integrate DMD<\/a> with Firefox, which will help drive about:memory’s “heap-unclassified” number down.\u00a0 They also do some sanity checking of memory reporters, and this checking has already found some bugs in existing reporters.<\/p>\n

Terrence Cole made the JS engine to a “shrink” GC on memory pressure events<\/a>, such as when about:memory’s “minimize memory usage” button is pressed.\u00a0 A “shrink” GC is one that causes unused pages to be decommitted.<\/p>\n

I wrote two pieces of documentation.<\/p>\n