Re: [PATCH v2 02/18] mini-os: remove unused alloc_contig_pages() function

[Samuel Thibault <samuel.thibault@ens-lyon.org>]

Juergen Gross, on Fri 05 Aug 2016 19:35:46 +0200, wrote:
> alloc_contig_pages() is never used anywhere in mini-os. Remove it.
> 
> Signed-off-by: Juergen Gross <jgross@suse.com>
> Reviewed-by: Wei Liu <wei.liu2@citrix.com>

Acked-by: Samuel Thibault <samuel.thibault@ens-lyon.org>

> ---
>  arch/x86/mm.c | 142 ----------------------------------------------------------
>  include/mm.h  |   1 -
>  2 files changed, 143 deletions(-)
> 
> diff --git a/arch/x86/mm.c b/arch/x86/mm.c
> index ae1036e..c59a5d3 100644
> --- a/arch/x86/mm.c
> +++ b/arch/x86/mm.c
> @@ -652,148 +652,6 @@ int unmap_frames(unsigned long va, unsigned long num_frames)
>  }
>  
>  /*
> - * Allocate pages which are contiguous in machine memory.
> - * Returns a VA to where they are mapped or 0 on failure.
> - * 
> - * addr_bits indicates if the region has restrictions on where it is
> - * located. Typical values are 32 (if for example PCI devices can't access
> - * 64bit memory) or 0 for no restrictions.
> - *
> - * Allocated pages can be freed using the page allocators free_pages() 
> - * function.
> - *
> - * based on Linux function xen_create_contiguous_region()
> - */
> -#define MAX_CONTIG_ORDER 9 /* 2MB */
> -unsigned long alloc_contig_pages(int order, unsigned int addr_bits)
> -{
> -    unsigned long in_va, va;
> -    unsigned long in_frames[1UL << order], out_frames, mfn;
> -    multicall_entry_t call[1UL << order];
> -    unsigned int i, num_pages = 1UL << order;
> -    int ret, exch_success;
> -
> -    /* pass in num_pages 'extends' of size 1 and
> -     * request 1 extend of size 'order */
> -    struct xen_memory_exchange exchange = {
> -        .in = {
> -            .nr_extents   = num_pages,
> -            .extent_order = 0,
> -            .domid        = DOMID_SELF
> -        },
> -        .out = {
> -            .nr_extents   = 1,
> -            .extent_order = order,
> -            .address_bits = addr_bits,
> -            .domid        = DOMID_SELF
> -        },
> -        .nr_exchanged = 0
> -    };
> -
> -    if ( order > MAX_CONTIG_ORDER )
> -    {
> -        printk("alloc_contig_pages: order too large 0x%x > 0x%x\n",
> -               order, MAX_CONTIG_ORDER);
> -        return 0;
> -    }
> -
> -    /* Allocate some potentially discontiguous pages */
> -    in_va = alloc_pages(order);
> -    if ( !in_va )
> -    {
> -        printk("alloc_contig_pages: could not get enough pages (order=0x%x\n",
> -               order);
> -        return 0;
> -    }
> -
> -    /* set up arguments for exchange hyper call */
> -    set_xen_guest_handle(exchange.in.extent_start, in_frames);
> -    set_xen_guest_handle(exchange.out.extent_start, &out_frames);
> -
> -    /* unmap current frames, keep a list of MFNs */
> -    for ( i = 0; i < num_pages; i++ )
> -    {
> -        int arg = 0;
> -
> -        va = in_va + (PAGE_SIZE * i);
> -        in_frames[i] = virt_to_mfn(va);
> -
> -        /* update P2M mapping */
> -        phys_to_machine_mapping[virt_to_pfn(va)] = INVALID_P2M_ENTRY;
> -
> -        /* build multi call */
> -        call[i].op = __HYPERVISOR_update_va_mapping;
> -        call[i].args[arg++] = va;
> -        call[i].args[arg++] = 0;
> -#ifdef __i386__
> -        call[i].args[arg++] = 0;
> -#endif  
> -        call[i].args[arg++] = UVMF_INVLPG;
> -    }
> -
> -    ret = HYPERVISOR_multicall(call, i);
> -    if ( ret )
> -    {
> -        printk("Odd, update_va_mapping hypercall failed with rc=%d.\n", ret);
> -        return 0;
> -    }
> -
> -    /* try getting a contig range of MFNs */
> -    out_frames = virt_to_pfn(in_va); /* PFNs to populate */
> -    ret = HYPERVISOR_memory_op(XENMEM_exchange, &exchange);
> -    if ( ret ) {
> -        printk("mem exchanged order=0x%x failed with rc=%d, nr_exchanged=%lu\n",
> -               order, ret, exchange.nr_exchanged);
> -        /* we still need to return the allocated pages above to the pool
> -         * ie. map them back into the 1:1 mapping etc. so we continue but 
> -         * in the end return the pages to the page allocator and return 0. */
> -        exch_success = 0;
> -    }
> -    else
> -        exch_success = 1;
> -
> -    /* map frames into 1:1 and update p2m */
> -    for ( i = 0; i < num_pages; i++ )
> -    {
> -        int arg = 0;
> -        pte_t pte;
> -
> -        va = in_va + (PAGE_SIZE * i);
> -        mfn = i < exchange.nr_exchanged ? (out_frames + i) : in_frames[i];
> -        pte = __pte(mfn << PAGE_SHIFT | L1_PROT);
> -
> -        /* update P2M mapping */
> -        phys_to_machine_mapping[virt_to_pfn(va)] = mfn;
> -
> -        /* build multi call */
> -        call[i].op = __HYPERVISOR_update_va_mapping;
> -        call[i].args[arg++] = va;
> -#ifdef __x86_64__
> -        call[i].args[arg++] = (pgentry_t)pte.pte;
> -#else
> -        call[i].args[arg++] = pte.pte_low;
> -        call[i].args[arg++] = pte.pte_high;
> -#endif  
> -        call[i].args[arg++] = UVMF_INVLPG;
> -    }
> -    ret = HYPERVISOR_multicall(call, i);
> -    if ( ret )
> -    {
> -        printk("update_va_mapping hypercall no. 2 failed with rc=%d.\n", ret);
> -        return 0;
> -    }
> -
> -    if ( !exch_success )
> -    {
> -        /* since the exchanged failed we just free the pages as well */
> -        free_pages((void *) in_va, order);
> -        return 0;
> -    }
> -    
> -    return in_va;
> -}
> -
> -/*
>   * Clear some of the bootstrap memory
>   */
>  static void clear_bootstrap(void)
> diff --git a/include/mm.h b/include/mm.h
> index f57d8ab..a48f485 100644
> --- a/include/mm.h
> +++ b/include/mm.h
> @@ -71,7 +71,6 @@ void do_map_frames(unsigned long addr,
>          const unsigned long *f, unsigned long n, unsigned long stride,
>  	unsigned long increment, domid_t id, int *err, unsigned long prot);
>  int unmap_frames(unsigned long va, unsigned long num_frames);
> -unsigned long alloc_contig_pages(int order, unsigned int addr_bits);
>  #ifdef HAVE_LIBC
>  extern unsigned long heap, brk, heap_mapped, heap_end;
>  #endif
> -- 
> 2.6.6
> 

-- 
Samuel
<c> ya(ka|ma|to)* ca existe une fois sur 2 au japon, c'est facile ;-)
 -+- #ens-mim au japon -+-

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