log speedup: walkchangerevs: filter the files only if we need them This speeds up hg log and significantly reduces memory usage (max RSS goes from ~92MB to ~21MB on the kernel repo), since we no longer store all the revisions in the cache.

#!/bin/sh
hg init
echo This is file a1 > a
hg add a
hg commit -m "commit #0" -d "1000000 0"
ls
echo This is file b1 > b
hg add b
hg commit -m "commit #1" -d "1000000 0"
hg co 0
# B should disappear
ls