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" <[email protected]>
Signed-off-by: "Chen, Tim C" <[email protected]>
Co-developed-by: "King, Colin" <[email protected]>
Signed-off-by: "King, Colin" <[email protected]>
Signed-off-by: rulinhuang <[email protected]>
---
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(-)
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
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" <[email protected]>
> Signed-off-by: "Chen, Tim C" <[email protected]>
> Co-developed-by: "King, Colin" <[email protected]>
> Signed-off-by: "King, Colin" <[email protected]>
> Signed-off-by: rulinhuang <[email protected]>
> ---
> 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 <[email protected]>
>
> 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
>
On Wed, Mar 06, 2024 at 09:14:40PM -0500, 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" <[email protected]>
> Signed-off-by: "Chen, Tim C" <[email protected]>
> Co-developed-by: "King, Colin" <[email protected]>
> Signed-off-by: "King, Colin" <[email protected]>
> Signed-off-by: rulinhuang <[email protected]>
> ---
> 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(-)
>
> 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
>
Thank you to be patient and thank you for your work!
Reviewed-by: Uladzislau Rezki (Sony) <[email protected]>
--
Uladzislau Rezki
On Wed, 6 Mar 2024 21:14:40 -0500 rulinhuang <[email protected]> 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.