On Wed, 6 Mar 2024 21:14:40 -0500 rulinhuang <rulin.huang@xxxxxxxxx> wrote: > When allocating a new memory area where the mapping address range is > known, it is observed that the vmap_node->busy.lock is acquired twice. > > The first acquisition occurs in the alloc_vmap_area() function when > inserting the vm area into the vm mapping red-black tree. The second > acquisition occurs in the setup_vmalloc_vm() function when updating the > properties of the vm, such as flags and address, etc. > > Combine these two operations together in alloc_vmap_area(), which > improves scalability when the vmap_node->busy.lock is contended. > By doing so, the need to acquire the lock twice can also be eliminated > to once. > > With the above change, tested on intel sapphire rapids > platform(224 vcpu), a 4% performance improvement is > gained on stress-ng/pthread(https://github.com/ColinIanKing/stress-ng), > which is the stress test of thread creations. > Thanks. We're late in -rc7 so I'll queue this up for merging in the next merge window.
