Re: [kvm-unit-tests PATCH v1 06/12] lib/alloc.h: remove align_min from struct alloc_ops

[Claudio Imbrenda <imbrenda@linux.ibm.com>]

On Thu, 24 Dec 2020 10:17:20 -0800
Krish Sadhukhan <krish.sadhukhan@oracle.com> wrote:

> On 12/16/20 12:11 PM, Claudio Imbrenda wrote:
> > Remove align_min from struct alloc_ops, since it is no longer used.
> >
> > Signed-off-by: Claudio Imbrenda<imbrenda@linux.ibm.com>
> > ---
> >   lib/alloc.h      | 1 -
> >   lib/alloc_page.c | 1 -
> >   lib/alloc_phys.c | 9 +++++----
> >   lib/vmalloc.c    | 1 -
> >   4 files changed, 5 insertions(+), 7 deletions(-)
> >
> > diff --git a/lib/alloc.h b/lib/alloc.h
> > index 9b4b634..db90b01 100644
> > --- a/lib/alloc.h
> > +++ b/lib/alloc.h
> > @@ -25,7 +25,6 @@
> >   struct alloc_ops {
> >   	void *(*memalign)(size_t alignment, size_t size);
> >   	void (*free)(void *ptr);
> > -	size_t align_min;
> >   };
> >   
> >   extern struct alloc_ops *alloc_ops;
> > diff --git a/lib/alloc_page.c b/lib/alloc_page.c
> > index 8d2700d..b1cdf21 100644
> > --- a/lib/alloc_page.c
> > +++ b/lib/alloc_page.c
> > @@ -385,7 +385,6 @@ void *memalign_pages_area(unsigned int area,
> > size_t alignment, size_t size) static struct alloc_ops
> > page_alloc_ops = { .memalign = memalign_pages,
> >   	.free = free_pages,
> > -	.align_min = PAGE_SIZE,
> >   };
> >   
> >   /*
> > diff --git a/lib/alloc_phys.c b/lib/alloc_phys.c
> > index 72e20f7..a4d2bf2 100644
> > --- a/lib/alloc_phys.c
> > +++ b/lib/alloc_phys.c
> > @@ -29,8 +29,8 @@ static phys_addr_t base, top;
> >   static void *early_memalign(size_t alignment, size_t size);
> >   static struct alloc_ops early_alloc_ops = {
> >   	.memalign = early_memalign,
> > -	.align_min = DEFAULT_MINIMUM_ALIGNMENT
> >   };
> > +static size_t align_min;  
> 
> 
> I don't see any caller of phys_alloc_set_minimum_alignment(). So when 

lib/arm/setup.c:150
lib/powerpc/setup.c:150

> you are comparing against this variable in phys_alloc_aligned_safe() 
> below, you are comparing against zero. Is that what you is intended
> or should 'align_min' be set some default ?

if the architecture specific code did not specify anything better, 0 is
ok.
 
> >   
> >   struct alloc_ops *alloc_ops = &early_alloc_ops;
> >   
> > @@ -39,8 +39,7 @@ void phys_alloc_show(void)
> >   	int i;
> >   
> >   	spin_lock(&lock);
> > -	printf("phys_alloc minimum alignment: %#" PRIx64 "\n",
> > -		(u64)early_alloc_ops.align_min);
> > +	printf("phys_alloc minimum alignment: %#" PRIx64 "\n",
> > (u64)align_min); for (i = 0; i < nr_regions; ++i)
> >   		printf("%016" PRIx64 "-%016" PRIx64 " [%s]\n",
> >   			(u64)regions[i].base,
> > @@ -64,7 +63,7 @@ void phys_alloc_set_minimum_alignment(phys_addr_t
> > align) {
> >   	assert(align && !(align & (align - 1)));
> >   	spin_lock(&lock);
> > -	early_alloc_ops.align_min = align;
> > +	align_min = align;
> >   	spin_unlock(&lock);
> >   }
> >   
> > @@ -83,6 +82,8 @@ static phys_addr_t
> > phys_alloc_aligned_safe(phys_addr_t size, top_safe = MIN(top_safe,
> > 1ULL << 32); 
> >   	assert(base < top_safe);
> > +	if (align < align_min)
> > +		align = align_min;
> >   
> >   	addr = ALIGN(base, align);
> >   	size += addr - base;
> > diff --git a/lib/vmalloc.c b/lib/vmalloc.c
> > index 7a49adf..e146162 100644
> > --- a/lib/vmalloc.c
> > +++ b/lib/vmalloc.c
> > @@ -190,7 +190,6 @@ static void vm_free(void *mem)
> >   static struct alloc_ops vmalloc_ops = {
> >   	.memalign = vm_memalign,
> >   	.free = vm_free,
> > -	.align_min = PAGE_SIZE,
> >   };
> >   
> >   void __attribute__((__weak__)) find_highmem(void)