New system calls: pidfd_open() and close_range()

Posted May 25, 2019 20:00 UTC (Sat) by pbonzini (subscriber, #60935)
In reply to: New system calls: pidfd_open() and close_range() by sorokin
Parent article: New system calls: pidfd_open() and close_range()

Technically walking a bitmap is O(size of the bitmap); from the point of view of big-O notation it doesn't matter that the constant in front of it is much smaller than the cost of actually closing those few open file descriptors.

However, walking the bitmap is for all purposes fast enough (a handful of instructions for 64 entries) that you can consider close_range to be linear in the number of file descriptors to be closed.