On 2/25/19 9:30 PM, Roman Gushchin wrote: > __vunmap() calls find_vm_area() twice without an obvious reason: > first directly to get the area pointer, second indirectly by calling > remove_vm_area(), which is again searching for the area. > > To remove this redundancy, let's split remove_vm_area() into > __remove_vm_area(struct vmap_area *), which performs the actual area > removal, and remove_vm_area(const void *addr) wrapper, which can > be used everywhere, where it has been used before. > > On my test setup, I've got 5-10% speed up on vfree()'ing 1000000 > of 4-pages vmalloc blocks. > > Perf report before: > 22.64% cat [kernel.vmlinux] [k] free_pcppages_bulk > 10.30% cat [kernel.vmlinux] [k] __vunmap > 9.80% cat [kernel.vmlinux] [k] find_vmap_area > 8.11% cat [kernel.vmlinux] [k] vunmap_page_range > 4.20% cat [kernel.vmlinux] [k] __slab_free > 3.56% cat [kernel.vmlinux] [k] __list_del_entry_valid > 3.46% cat [kernel.vmlinux] [k] smp_call_function_many > 3.33% cat [kernel.vmlinux] [k] kfree > 3.32% cat [kernel.vmlinux] [k] free_unref_page > > Perf report after: > 23.01% cat [kernel.kallsyms] [k] free_pcppages_bulk > 9.46% cat [kernel.kallsyms] [k] __vunmap > 9.15% cat [kernel.kallsyms] [k] vunmap_page_range > 6.17% cat [kernel.kallsyms] [k] __slab_free > 5.61% cat [kernel.kallsyms] [k] kfree > 4.86% cat [kernel.kallsyms] [k] bad_range > 4.67% cat [kernel.kallsyms] [k] free_unref_page_commit > 4.24% cat [kernel.kallsyms] [k] __list_del_entry_valid > 3.68% cat [kernel.kallsyms] [k] free_unref_page > 3.65% cat [kernel.kallsyms] [k] __list_add_valid > 3.19% cat [kernel.kallsyms] [k] __purge_vmap_area_lazy > 3.10% cat [kernel.kallsyms] [k] find_vmap_area > 3.05% cat [kernel.kallsyms] [k] rcu_cblist_dequeue > > Signed-off-by: Roman Gushchin <guro@xxxxxx> > Cc: Johannes Weiner <hannes@xxxxxxxxxxx> > Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
