On Wed, Dec 05, 2018 at 02:49:39PM +0800, Xin Long wrote:
> Without the support for the total_nr_elements's growing or shrinking
> dynamically, flex_array is not that 'flexible'. Like when users want
> to change the size, they have to redo flex_array_alloc and copy all
> the elements from the old to the new one. The worse thing is every
> element's memory gets changed.
>
> To implement flex_array_resize based on current code, the difficult
> thing is to process the size border of FLEX_ARRAY_BASE_BYTES_LEFT,
> where the base data memory may change to an array for the 2nd level
> data memory for growing, likewise for shrinking.
>
> To make this part easier, we separate the base data memory and define
> FLEX_ARRAY_BASE_SIZE as a same value of FLEX_ARRAY_PART_SIZE, as Neil
> suggested. When new size is crossing the border, the base memory is
> allocated as the array for the 2nd level data memory and its part[0]
> is pointed to the old base memory, and do the opposite for shrinking.
>
> But it doesn't do any memory allocation or shrinking for elements in
> flex_array_resize, as which should be done by flex_array_prealloc or
> flex_array_shrink called by users. No memory leaks can be caused by
> that.
>
> SCTP has benefited a lot from flex_array_resize() for managing its
> stream memory so far.
>
> Xin Long (3):
> flex_array: make FLEX_ARRAY_BASE_SIZE the same value of
> FLEX_ARRAY_PART_SIZE
> flex_array: support flex_array_resize
> sctp: fa_resize sctp stream instead of redo fa_alloc
>
> include/linux/flex_array.h | 40 ++++++++++-----------
> lib/flex_array.c | 73 ++++++++++++++++++++++++++++++++++++--
> net/sctp/stream.c | 87
> +++++++++++++++++++++-------------------------
> 3 files changed, 130 insertions(+), 70 deletions(-)
>
> --
> 2.1.0
>
>
Series
Acked-by: Neil Horman <nhor...@tuxdriver.com>
