Eric Dumazet wrote: > Database workload, where the user multi threaded app is constantly > accessing GBytes of data, so L2 cache hit is very small. If you want to > oprofile it, with say a CPU_CLK_UNHALTED:5000 event, then find_vma() is > in the top 5.
We did have a workload with lots of Java and databases at some point when many VMAs were the issue. I brought this up here one, maybe two years ago and I think Blaisorblade went on and looked into avoiding VMA splits by having mprotect() not split VMAs and instead store the flags in the page table somewhere. I don't remember the details. Nothing came out of this but if this is possible it would be yet another way to avoid mmap_sem locking, right? -- ➧ Ulrich Drepper ➧ Red Hat, Inc. ➧ 444 Castro St ➧ Mountain View, CA ❖
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