3 ms·
There's a better explanation here, though I still don't understand "34-bit unsigned second counter right shifted two bits" and "(((2^34-1) + (2^31-1)) & ~3)":
by bloak 6y ago
There's a better explanation here, though I still don't understand "34-bit unsigned second counter right shifted two bits" and "(((2^34-1) + (2^31-1)) & ~3)":
https://lwn.net/Articles/829314/ https://lwn.net/Articles/829314/
- StringyBob 6y agoA bit mysterious, but seems as files will now have nanosecond accuracy since 1901 (in the 64bit unsigned int), the quota timers are still 32bit and have been downgraded from 1 second to 4 second accuracy to cover the full bigtime forward time range required (for 1970 unix epoch). Seems to be described in this patch comment: https://patchwork.kernel.org/project/xfs/patch/157784114490.1364230.7521571821422773694.stgit@magnolia/ https://patchwork.kernel.org/project/xfs/patch/157784114490....
- deleted 6y ago[deleted]
- dschuler 6y agoIt’s not totally clear to me either, but maybe it’s a 32-bit value treated as a 34-bit value with a precision of 4 seconds (so left-shifted two bits elsewhere), since the whole term has the least significant two bits cleared with ‘& ~3’. No idea what the (2^31-1) term is doing though.