From 1af5f730fc1bf7c62ec9fb2d307206e18bf40a69 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 24 Oct 2008 11:06:13 +0200 Subject: [PATCH] sched: more accurate min_vruntime accounting Mike noticed the current min_vruntime tracking can go wrong and skip the current task. If the only remaining task in the tree is a nice 19 task with huge vruntime, new tasks will be inserted too far to the right too, causing some interactibity issues. min_vruntime can only change due to the leftmost entry disappearing (dequeue_entity()), or by the leftmost entry being incremented past the next entry, which elects a new leftmost (__update_curr()) Due to the current entry not being part of the actual tree, we have to compare the leftmost tree entry with the current entry, and take the leftmost of these two. So create a update_min_vruntime() function that takes computes the leftmost vruntime in the system (either tree of current) and increases the cfs_rq->min_vruntime if the computed value is larger than the previously found min_vruntime. And call this from the two sites we've identified that can change min_vruntime. Reported-by: Mike Galbraith Signed-off-by: Peter Zijlstra Acked-by: Mike Galbraith Signed-off-by: Ingo Molnar --- Reading git-format-patch failed