Not sure what went down, something crashed bitcoind, which is unusual on my server.
The congested mempool that we've had recently from the 14kB blocks is causing excessive memory consumption. From my investigation so far, it looks like there's a memory leak in getblocktemplate/CreateNewBlock. This makes bitcoind's memory consumption increase by as much as 1 GB per day. I've been restarting my bitcoind processes every 2 days or so.