On 03/07/24 at 08:16pm, Uladzislau Rezki wrote: > On Thu, Mar 07, 2024 at 09:23:10AM +0800, Baoquan He wrote: > > On 03/06/24 at 08:01pm, Uladzislau Rezki wrote: > > > On Fri, Mar 01, 2024 at 10:54:16AM -0500, rulinhuang wrote: > > ...... > > > > > > Sorry for the late answer, i also just noticed this email. It was not in > > > my inbox... > > > > > > OK, now you move part of the per-cpu allocator on the top and leave > > > another part down making it split. This is just for the: > > > > > > BUG_ON(va_flags & VMAP_RAM); > > > > > > VMAP_RAM macro. Do we really need this BUG_ON()? > > > > Sorry, I suggested that when reviewing v5: > > https://lore.kernel.org/all/ZdiltpK5fUvwVWtD@MiWiFi-R3L-srv/T/#u > > > > About part of per-cpu kva allocator moving and the split making, I would > > argue that we will have vmap_nodes defintion and basic helper functions > > like addr_to_node_id() etc at top, and leave other part like > > size_to_va_pool(), node_pool_add_va() etc down. These are similar. > > > > While about whether we should add 'BUG_ON(va_flags & VMAP_RAM);', I am > > not sure about it. When I suggested that, I am also hesitant. From the > > current code, alloc_vmap_area() is called in below three functions, only > > __get_vm_area_node() will pass the non-NULL vm. > > new_vmap_block() -| > > vm_map_ram() ----> alloc_vmap_area() > > __get_vm_area_node() -| > > > > It could be wrongly passed in the future? Only checking if vm is > > non-NULL makes me feel a little unsafe. While I am fine if removing the > > BUG_ON, because there's no worry in the current code. We can wait and > > see in the future. > > > > if (vm) { > > BUG_ON(va_flags & VMAP_RAM); > > setup_vmalloc_vm(vm, va, flags, caller); > > } > > > I would remove it, because it is really hard to mess it, there is only > one place also BUG_ON() is really a show stopper. I really appreciate > what rulinhuang <rulin.huang@xxxxxxxxx> is doing and i understand that > it might be not so easy. I agree, I was hesitant, now it firms up my mind. > > So, if we can avoid of moving the code, that looks to me that we can do, > if we can pass less arguments into alloc_vmap_area() since it is overloaded > that would be great. Agree too, less arguments is much better. While I personnally prefer the open coding a little bit like below. There is suspicion of excessive packaging in __pre/__post_setup_vmalloc_vm() wrapping. They are very simple and few assignments after all. --- mm/vmalloc.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 0fd8ebaad17b..0c738423976d 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -1924,8 +1924,7 @@ 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, struct vm_struct *vm, - unsigned long flags, const void *caller) + unsigned long va_flags, struct vm_struct *vm) { struct vmap_node *vn; struct vmap_area *va; @@ -1988,8 +1987,11 @@ 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); + if (vm) { + vm->addr = (void *)va->va_start; + vm->size = va->va_end - va->va_start; + va->vm = vm; + } vn = addr_to_node(va->va_start); @@ -2565,8 +2567,7 @@ 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, NULL, - 0, NULL); + VMAP_RAM|VMAP_BLOCK, NULL); if (IS_ERR(va)) { kfree(vb); return ERR_CAST(va); @@ -2924,7 +2925,7 @@ void *vm_map_ram(struct page **pages, unsigned int count, int node) va = alloc_vmap_area(size, PAGE_SIZE, VMALLOC_START, VMALLOC_END, node, GFP_KERNEL, VMAP_RAM, - NULL, 0, NULL); + NULL); if (IS_ERR(va)) return NULL; @@ -3063,7 +3064,10 @@ 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, area, flags, caller); + area->flags = flags; + area->caller = caller; + + va = alloc_vmap_area(size, align, start, end, node, gfp_mask, 0, area); if (IS_ERR(va)) { kfree(area); return NULL; -- 2.41.0 > > Just an example: > > <snip> > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index 25a8df497255..b6050e018539 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -1841,6 +1841,30 @@ node_alloc(unsigned long size, unsigned long align, > return va; > } > > +static inline void > +__pre_setup_vmalloc_vm(struct vm_struct *vm, > + unsigned long flags, const void *caller) > +{ > + vm->flags = flags; > + vm->caller = caller; > +} > + > +static inline void > +__post_setup_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va) > +{ > + vm->addr = (void *)va->va_start; > + vm->size = va->va_end - va->va_start; > + va->vm = vm; > +} > + > +static inline void > +setup_vmalloc_vm_locked(struct vm_struct *vm, struct vmap_area *va, > + unsigned long flags, const void *caller) > +{ > + __pre_setup_vmalloc_vm(vm, flags, caller); > + __post_setup_vmalloc_vm(vm, va); > +} > + > /* > * Allocate a region of KVA of the specified size and alignment, within the > * vstart and vend. > @@ -1849,7 +1873,7 @@ 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) > { > struct vmap_node *vn; > struct vmap_area *va; > @@ -1912,6 +1936,9 @@ static struct vmap_area *alloc_vmap_area(unsigned long size, > va->vm = NULL; > va->flags = (va_flags | vn_id); > > + if (vm) > + __post_setup_vmalloc_vm(vm, va); > + > vn = addr_to_node(va->va_start); > > spin_lock(&vn->busy.lock); > @@ -2486,7 +2513,7 @@ 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); > if (IS_ERR(va)) { > kfree(vb); > return ERR_CAST(va); > @@ -2843,7 +2870,8 @@ 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); > + > if (IS_ERR(va)) > return NULL; > > @@ -2946,26 +2974,6 @@ 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 +3010,15 @@ 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); > + /* post-setup is done in the alloc_vmap_area(). */ > + __pre_setup_vmalloc_vm(area, flags, caller); > + > + va = alloc_vmap_area(size, align, start, end, node, gfp_mask, 0, area); > 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. > <snip> > > -- > Uladzislau Rezki >
