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From: Uladzislau Rezki <urezki@gmail.com>
Date: Fri, 8 Mar 2024 11:28:05 +0100
To: Baoquan He <bhe@redhat.com>
Cc: Uladzislau Rezki <urezki@gmail.com>, rulinhuang <rulin.huang@intel.com>,
	akpm@linux-foundation.org, colin.king@intel.com, hch@infradead.org,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	lstoakes@gmail.com, tianyou.li@intel.com, tim.c.chen@intel.com,
	wangyang.guo@intel.com, zhiguo.zhou@intel.com
Subject: Re: [PATCH v7 1/2] mm/vmalloc: Moved macros with no functional
 change happened
Message-ID: <ZeroNTcyEMx6jiZF@pc636>
References: <20240301155417.1852290-1-rulin.huang@intel.com>
 <20240301155417.1852290-2-rulin.huang@intel.com>
 <Zei9n-VMxtzG8z4Y@pc636>
 <ZekW/nGXfTqOlvPZ@MiWiFi-R3L-srv>
 <ZeoSiP-hOeHG89BJ@pc638.lan>
 <ZerLB/LNWAOvC2HM@MiWiFi-R3L-srv>
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In-Reply-To: <ZerLB/LNWAOvC2HM@MiWiFi-R3L-srv>

> > 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@intel.com> 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
> 
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>

Looks even better :) It can be applied on on top of:

[PATCH v8] mm/vmalloc: Eliminated the lock contention from twice to once

We are a bit ahead since v8 will be taken later. Anyway please use the
reviewed-by tag once you send a complete patch. 

Thanks!

--
Uladzislau Rezki