Re: [Xen-devel] [PATCH v2 COLOPre 04/13] tools/libxc: export xc_bitops.h

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

On Thu, 2015-06-11 at 10:07 +0800, Yang Hongyang wrote:
> 
> On 06/10/2015 11:20 PM, Ian Campbell wrote:
> > On Mon, 2015-06-08 at 11:43 +0800, Yang Hongyang wrote:
> >> When we are under COLO, we will send dirty page bitmap info from
> >> secondary to primary at every checkpoint.
> >
> > ... and this is a _libxl_ operation? Is that the right layer here?
> 
> For the first question, Yes, this is done in the suspend callback on
> restore side. We do this in libxl because currently we only added a
> back channel on libxl side. There're no back channel in libxc.
> 
> By considering this more, if we do this in libxc part, the code will be
> less complex: we can drop the 4th & 9th patch of this series and also
> get rid of the get_dirty_pfn() callback. instead we will add a patch to
> add back channel in libxc.

That sounds better to me, but lets see what Andrew thinks.

> 
> For the second question, I'm not sure, what's Andrew's opinion? which
> is the right layer to do this operation, libxl or libxc?
> 
> >
> >>   So we need to get/test
> >> the dirty page bitmap. We just expose xc_bitops.h for libxl use.
> >>
> >> NOTE:
> >>    Need to make clean and rerun configure to get it compiled.
> >>
> >> Signed-off-by: Yang Hongyang <yanghy@xxxxxxxxxxxxxx>
> >> ---
> >>   tools/libxc/include/xc_bitops.h | 76 
> >> +++++++++++++++++++++++++++++++++++++++++
> >>   tools/libxc/xc_bitops.h         | 76 
> >> -----------------------------------------
> >>   2 files changed, 76 insertions(+), 76 deletions(-)
> >>   create mode 100644 tools/libxc/include/xc_bitops.h
> >>   delete mode 100644 tools/libxc/xc_bitops.h
> >>
> >> diff --git a/tools/libxc/include/xc_bitops.h 
> >> b/tools/libxc/include/xc_bitops.h
> >> new file mode 100644
> >> index 0000000..cd749f4
> >> --- /dev/null
> >> +++ b/tools/libxc/include/xc_bitops.h
> >> @@ -0,0 +1,76 @@
> >> +#ifndef XC_BITOPS_H
> >> +#define XC_BITOPS_H 1
> >> +
> >> +/* bitmap operations for single threaded access */
> >> +
> >> +#include <stdlib.h>
> >> +#include <string.h>
> >> +
> >> +#define BITS_PER_LONG (sizeof(unsigned long) * 8)
> >> +#define ORDER_LONG (sizeof(unsigned long) == 4 ? 5 : 6)
> >> +
> >> +#define BITMAP_ENTRY(_nr,_bmap) ((_bmap))[(_nr)/BITS_PER_LONG]
> >> +#define BITMAP_SHIFT(_nr) ((_nr) % BITS_PER_LONG)
> >> +
> >> +/* calculate required space for number of longs needed to hold nr_bits */
> >> +static inline int bitmap_size(int nr_bits)
> >> +{
> >> +    int nr_long, nr_bytes;
> >> +    nr_long = (nr_bits + BITS_PER_LONG - 1) >> ORDER_LONG;
> >> +    nr_bytes = nr_long * sizeof(unsigned long);
> >> +    return nr_bytes;
> >> +}
> >> +
> >> +static inline unsigned long *bitmap_alloc(int nr_bits)
> >> +{
> >> +    return calloc(1, bitmap_size(nr_bits));
> >> +}
> >> +
> >> +static inline void bitmap_set(unsigned long *addr, int nr_bits)
> >> +{
> >> +    memset(addr, 0xff, bitmap_size(nr_bits));
> >> +}
> >> +
> >> +static inline void bitmap_clear(unsigned long *addr, int nr_bits)
> >> +{
> >> +    memset(addr, 0, bitmap_size(nr_bits));
> >> +}
> >> +
> >> +static inline int test_bit(int nr, unsigned long *addr)
> >> +{
> >> +    return (BITMAP_ENTRY(nr, addr) >> BITMAP_SHIFT(nr)) & 1;
> >> +}
> >> +
> >> +static inline void clear_bit(int nr, unsigned long *addr)
> >> +{
> >> +    BITMAP_ENTRY(nr, addr) &= ~(1UL << BITMAP_SHIFT(nr));
> >> +}
> >> +
> >> +static inline void set_bit(int nr, unsigned long *addr)
> >> +{
> >> +    BITMAP_ENTRY(nr, addr) |= (1UL << BITMAP_SHIFT(nr));
> >> +}
> >> +
> >> +static inline int test_and_clear_bit(int nr, unsigned long *addr)
> >> +{
> >> +    int oldbit = test_bit(nr, addr);
> >> +    clear_bit(nr, addr);
> >> +    return oldbit;
> >> +}
> >> +
> >> +static inline int test_and_set_bit(int nr, unsigned long *addr)
> >> +{
> >> +    int oldbit = test_bit(nr, addr);
> >> +    set_bit(nr, addr);
> >> +    return oldbit;
> >> +}
> >> +
> >> +static inline void bitmap_or(unsigned long *dst, const unsigned long 
> >> *other,
> >> +                             int nr_bits)
> >> +{
> >> +    int i, nr_longs = (bitmap_size(nr_bits) / sizeof(unsigned long));
> >> +    for ( i = 0; i < nr_longs; ++i )
> >> +        dst[i] |= other[i];
> >> +}
> >> +
> >> +#endif  /* XC_BITOPS_H */
> >> diff --git a/tools/libxc/xc_bitops.h b/tools/libxc/xc_bitops.h
> >> deleted file mode 100644
> >> index cd749f4..0000000
> >> --- a/tools/libxc/xc_bitops.h
> >> +++ /dev/null
> >> @@ -1,76 +0,0 @@
> >> -#ifndef XC_BITOPS_H
> >> -#define XC_BITOPS_H 1
> >> -
> >> -/* bitmap operations for single threaded access */
> >> -
> >> -#include <stdlib.h>
> >> -#include <string.h>
> >> -
> >> -#define BITS_PER_LONG (sizeof(unsigned long) * 8)
> >> -#define ORDER_LONG (sizeof(unsigned long) == 4 ? 5 : 6)
> >> -
> >> -#define BITMAP_ENTRY(_nr,_bmap) ((_bmap))[(_nr)/BITS_PER_LONG]
> >> -#define BITMAP_SHIFT(_nr) ((_nr) % BITS_PER_LONG)
> >> -
> >> -/* calculate required space for number of longs needed to hold nr_bits */
> >> -static inline int bitmap_size(int nr_bits)
> >> -{
> >> -    int nr_long, nr_bytes;
> >> -    nr_long = (nr_bits + BITS_PER_LONG - 1) >> ORDER_LONG;
> >> -    nr_bytes = nr_long * sizeof(unsigned long);
> >> -    return nr_bytes;
> >> -}
> >> -
> >> -static inline unsigned long *bitmap_alloc(int nr_bits)
> >> -{
> >> -    return calloc(1, bitmap_size(nr_bits));
> >> -}
> >> -
> >> -static inline void bitmap_set(unsigned long *addr, int nr_bits)
> >> -{
> >> -    memset(addr, 0xff, bitmap_size(nr_bits));
> >> -}
> >> -
> >> -static inline void bitmap_clear(unsigned long *addr, int nr_bits)
> >> -{
> >> -    memset(addr, 0, bitmap_size(nr_bits));
> >> -}
> >> -
> >> -static inline int test_bit(int nr, unsigned long *addr)
> >> -{
> >> -    return (BITMAP_ENTRY(nr, addr) >> BITMAP_SHIFT(nr)) & 1;
> >> -}
> >> -
> >> -static inline void clear_bit(int nr, unsigned long *addr)
> >> -{
> >> -    BITMAP_ENTRY(nr, addr) &= ~(1UL << BITMAP_SHIFT(nr));
> >> -}
> >> -
> >> -static inline void set_bit(int nr, unsigned long *addr)
> >> -{
> >> -    BITMAP_ENTRY(nr, addr) |= (1UL << BITMAP_SHIFT(nr));
> >> -}
> >> -
> >> -static inline int test_and_clear_bit(int nr, unsigned long *addr)
> >> -{
> >> -    int oldbit = test_bit(nr, addr);
> >> -    clear_bit(nr, addr);
> >> -    return oldbit;
> >> -}
> >> -
> >> -static inline int test_and_set_bit(int nr, unsigned long *addr)
> >> -{
> >> -    int oldbit = test_bit(nr, addr);
> >> -    set_bit(nr, addr);
> >> -    return oldbit;
> >> -}
> >> -
> >> -static inline void bitmap_or(unsigned long *dst, const unsigned long 
> >> *other,
> >> -                             int nr_bits)
> >> -{
> >> -    int i, nr_longs = (bitmap_size(nr_bits) / sizeof(unsigned long));
> >> -    for ( i = 0; i < nr_longs; ++i )
> >> -        dst[i] |= other[i];
> >> -}
> >> -
> >> -#endif  /* XC_BITOPS_H */
> >
> >
> > .
> >
> 



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