Re: [PATCH v2 1/9] mm: vmalloc: Add va_alloc() helper

From: Uladzislau Rezki <urezki@gmail.com>
To: Baoquan He <bhe@redhat.com>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>,
	linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Lorenzo Stoakes <lstoakes@gmail.com>,
	Christoph Hellwig <hch@infradead.org>,
	Matthew Wilcox <willy@infradead.org>,
	"Liam R . Howlett" <Liam.Howlett@oracle.com>,
	Dave Chinner <david@fromorbit.com>,
	"Paul E . McKenney" <paulmck@kernel.org>,
	Joel Fernandes <joel@joelfernandes.org>,
	Oleksiy Avramchenko <oleksiy.avramchenko@sony.com>,
	Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v2 1/9] mm: vmalloc: Add va_alloc() helper
Date: Wed, 6 Sep 2023 17:06:22 +0200	[thread overview]
Message-ID: <ZPiVbvdtoDob7fA+@pc636> (raw)
In-Reply-To: <ZPgTR19GX9EI8J0d@MiWiFi-R3L-srv>

On Wed, Sep 06, 2023 at 01:51:03PM +0800, Baoquan He wrote:
> On 08/29/23 at 10:11am, Uladzislau Rezki (Sony) wrote:
> > Currently __alloc_vmap_area() function contains an open codded
> > logic that finds and adjusts a VA based on allocation request.
> > 
> > Introduce a va_alloc() helper that adjusts found VA only. It
> > will be used later at least in two places.
> > 
> > There is no a functional change as a result of this patch.
> > 
> > Reviewed-by: Christoph Hellwig <hch@lst.de>
> > Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
> > Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
> > ---
> >  mm/vmalloc.c | 41 ++++++++++++++++++++++++++++-------------
> >  1 file changed, 28 insertions(+), 13 deletions(-)
> > 
> > diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> > index 93cf99aba335..00afc1ee4756 100644
> > --- a/mm/vmalloc.c
> > +++ b/mm/vmalloc.c
> > @@ -1481,6 +1481,32 @@ adjust_va_to_fit_type(struct rb_root *root, struct list_head *head,
> >  	return 0;
> >  }
> >  
> > +static unsigned long
> > +va_alloc(struct vmap_area *va,
> > +		struct rb_root *root, struct list_head *head,
> > +		unsigned long size, unsigned long align,
> > +		unsigned long vstart, unsigned long vend)
> > +{
> > +	unsigned long nva_start_addr;
> > +	int ret;
> > +
> > +	if (va->va_start > vstart)
> > +		nva_start_addr = ALIGN(va->va_start, align);
> > +	else
> > +		nva_start_addr = ALIGN(vstart, align);
> > +
> > +	/* Check the "vend" restriction. */
> > +	if (nva_start_addr + size > vend)
> > +		return vend;
> > +
> > +	/* Update the free vmap_area. */
> > +	ret = adjust_va_to_fit_type(root, head, va, nva_start_addr, size);
> > +	if (WARN_ON_ONCE(ret))
> > +		return vend;
> > +
> > +	return nva_start_addr;
> > +}
> > +
> >  /*
> >   * Returns a start address of the newly allocated area, if success.
> >   * Otherwise a vend is returned that indicates failure.
> > @@ -1493,7 +1519,6 @@ __alloc_vmap_area(struct rb_root *root, struct list_head *head,
> >  	bool adjust_search_size = true;
> >  	unsigned long nva_start_addr;
> >  	struct vmap_area *va;
> > -	int ret;
> >  
> >  	/*
> >  	 * Do not adjust when:
> > @@ -1511,18 +1536,8 @@ __alloc_vmap_area(struct rb_root *root, struct list_head *head,
> >  	if (unlikely(!va))
> >  		return vend;
> >  
> > -	if (va->va_start > vstart)
> > -		nva_start_addr = ALIGN(va->va_start, align);
> > -	else
> > -		nva_start_addr = ALIGN(vstart, align);
> > -
> > -	/* Check the "vend" restriction. */
> > -	if (nva_start_addr + size > vend)
> > -		return vend;
> > -
> > -	/* Update the free vmap_area. */
> > -	ret = adjust_va_to_fit_type(root, head, va, nva_start_addr, size);
> > -	if (WARN_ON_ONCE(ret))
> > +	nva_start_addr = va_alloc(va, root, head, size, align, vstart, vend);
> > +	if (nva_start_addr == vend)
> >  		return vend;
> >  
> >  #if DEBUG_AUGMENT_LOWEST_MATCH_CHECK
> > -- 
> > 2.30.2
> 
> Reviewed-by: Baoquan He <bhe@redhat.com>
> 
Thanks, i picked it for V3.

--
Uladzislau Rezki