Differential D39881
Handle MAXCPU bloat for amd64 pmap Authored by kib on Apr 30 2023, 2:20 AM.
Details vm: allow arches to request extents to the pre-defined struct pmap storage amd64: only allocate as many pmap_pcids entries for pmap as needed instead of maxing at MAXCPU. Note that pmap still reserves MAXCPU entries for the kernel pmap, because it is allocated statically and must be initialized very early.
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Comment Actions does it have to be allocated in one chunk? i note the massive false sharing due to the maxcpu array which is retained after this change can this move to per-cpu alloc for the remainder? this is the kind of step which will have to happen anyway at some point and it will require reworking this change, why not do it now Comment Actions Right now yes, due to kernel_pmap needed to be initialized very early.
Then the kernel_pmap needs to be re-initialized somehow, it is much larger and complex change. | ||||||||||