When compiling modules with many functions, the list of regions in the
{DisjointAllocationPool} can become quite large if the functions die in
a random order (which they typically do, since the order of Liftoff
compilation is different than the order to TurboFan compilation; which
work stealing, both are nondeterministic).
Iterating the list of regions in the {DisjointAllocationPool} was thus
linear in the number of regions, which is linear in the number of
functions of the module. Since we insert new regions one by one, overall
runtime was quadratic.
This CL fixes this by switching from a linked list to a std::set.
Merging a new region is thus logarithmic instead of linear, and overall
we are {n*log(n)} instead of {n^2}.
Note: For {AllocateInRegion} we still need to linearly iterate all
regions that overlap the requested region, but this has not shown to be
a problem so far.
R=ahaas@chromium.org
Bug: v8:10432
Change-Id: I193e56c2abab782e386194fbe64dadfa250916f7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2154797
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67303}
7e0279fae7