On 03/06/24 at 09:14pm, rulinhuang 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. > > Co-developed-by: "Chen, Tim C" <tim.c.chen@xxxxxxxxx> > Signed-off-by: "Chen, Tim C" <tim.c.chen@xxxxxxxxx> > Co-developed-by: "King, Colin" <colin.king@xxxxxxxxx> > Signed-off-by: "King, Colin" <colin.king@xxxxxxxxx> > Signed-off-by: rulinhuang <rulin.huang@xxxxxxxxx> > --- > V1 -> V2: Avoided the partial initialization issue of vm and > separated insert_vmap_area() from alloc_vmap_area() > V2 -> V3: Rebased on 6.8-rc5 > V3 -> V4: Rebased on mm-unstable branch > V4 -> V5: Canceled the split of alloc_vmap_area() > and keep insert_vmap_area() > V5 -> V6: Added bug_on > V6 -> V7: Adjusted the macros > V7 -> V8: Removed bugs_on and adjustion of macros > --- > mm/vmalloc.c | 50 ++++++++++++++++++++++---------------------------- > 1 file changed, 22 insertions(+), 28 deletions(-) LGTM, Reviewed-by: Baoquan He <bhe@xxxxxxxxxx> > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index 25a8df497255..f933a62fef50 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -1841,15 +1841,26 @@ node_alloc(unsigned long size, unsigned long align, > return va; > } > > +static inline void setup_vmalloc_vm(struct vm_struct *vm, > + struct vmap_area *va, unsigned long flags, const void *caller) > +{ > + vm->flags = flags; > + vm->addr = (void *)va->va_start; > + vm->size = va->va_end - va->va_start; > + vm->caller = caller; > + va->vm = vm; > +} > + > /* > * Allocate a region of KVA of the specified size and alignment, within the > - * vstart and vend. > + * vstart and vend. If vm is passed in, the two will also be bound. > */ > static struct vmap_area *alloc_vmap_area(unsigned long size, > unsigned long align, > unsigned long vstart, unsigned long vend, > int node, gfp_t gfp_mask, > - unsigned long va_flags) > + unsigned long va_flags, struct vm_struct *vm, > + unsigned long flags, const void *caller) > { > struct vmap_node *vn; > struct vmap_area *va; > @@ -1912,6 +1923,9 @@ static struct vmap_area *alloc_vmap_area(unsigned long size, > va->vm = NULL; > va->flags = (va_flags | vn_id); > > + if (vm) > + setup_vmalloc_vm(vm, va, flags, caller); > + > vn = addr_to_node(va->va_start); > > spin_lock(&vn->busy.lock); > @@ -2486,7 +2500,8 @@ static void *new_vmap_block(unsigned int order, gfp_t gfp_mask) > va = alloc_vmap_area(VMAP_BLOCK_SIZE, VMAP_BLOCK_SIZE, > VMALLOC_START, VMALLOC_END, > node, gfp_mask, > - VMAP_RAM|VMAP_BLOCK); > + VMAP_RAM|VMAP_BLOCK, NULL, > + 0, NULL); > if (IS_ERR(va)) { > kfree(vb); > return ERR_CAST(va); > @@ -2843,7 +2858,8 @@ void *vm_map_ram(struct page **pages, unsigned int count, int node) > struct vmap_area *va; > va = alloc_vmap_area(size, PAGE_SIZE, > VMALLOC_START, VMALLOC_END, > - node, GFP_KERNEL, VMAP_RAM); > + node, GFP_KERNEL, VMAP_RAM, > + NULL, 0, NULL); > if (IS_ERR(va)) > return NULL; > > @@ -2946,26 +2962,6 @@ void __init vm_area_register_early(struct vm_struct *vm, size_t align) > kasan_populate_early_vm_area_shadow(vm->addr, vm->size); > } > > -static inline void setup_vmalloc_vm_locked(struct vm_struct *vm, > - struct vmap_area *va, unsigned long flags, const void *caller) > -{ > - vm->flags = flags; > - vm->addr = (void *)va->va_start; > - vm->size = va->va_end - va->va_start; > - vm->caller = caller; > - va->vm = vm; > -} > - > -static void setup_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va, > - unsigned long flags, const void *caller) > -{ > - struct vmap_node *vn = addr_to_node(va->va_start); > - > - spin_lock(&vn->busy.lock); > - setup_vmalloc_vm_locked(vm, va, flags, caller); > - spin_unlock(&vn->busy.lock); > -} > - > static void clear_vm_uninitialized_flag(struct vm_struct *vm) > { > /* > @@ -3002,14 +2998,12 @@ static struct vm_struct *__get_vm_area_node(unsigned long size, > if (!(flags & VM_NO_GUARD)) > size += PAGE_SIZE; > > - va = alloc_vmap_area(size, align, start, end, node, gfp_mask, 0); > + va = alloc_vmap_area(size, align, start, end, node, gfp_mask, 0, area, flags, caller); > if (IS_ERR(va)) { > kfree(area); > return NULL; > } > > - setup_vmalloc_vm(area, va, flags, caller); > - > /* > * Mark pages for non-VM_ALLOC mappings as accessible. Do it now as a > * best-effort approach, as they can be mapped outside of vmalloc code. > @@ -4584,7 +4578,7 @@ struct vm_struct **pcpu_get_vm_areas(const unsigned long *offsets, > > spin_lock(&vn->busy.lock); > insert_vmap_area(vas[area], &vn->busy.root, &vn->busy.head); > - setup_vmalloc_vm_locked(vms[area], vas[area], VM_ALLOC, > + setup_vmalloc_vm(vms[area], vas[area], VM_ALLOC, > pcpu_get_vm_areas); > spin_unlock(&vn->busy.lock); > } > > base-commit: f4239a5d7acc1b5ff9bac4d5471000b952279ef0 > -- > 2.43.0 >
