Messages in this thread | | | Date | Wed, 10 Mar 2021 18:27:53 +0100 | From | Oleg Nesterov <> | Subject | Re: [PATCH v3] do_wait: make PIDTYPE_PID case O(1) instead of O(n) |
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On 03/09, Jim Newsome wrote: > > do_wait is an internal function used to implement waitpid, waitid, > wait4, etc. To handle the general case, it does an O(n) linear scan of > the thread group's children and tracees. > > This patch adds a special-case when waiting on a pid to skip these scans > and instead do an O(1) lookup. This improves performance when waiting on > a pid from a thread group with many children and/or tracees. > > Signed-off-by: James Newsome <jnewsome@torproject.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
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