• Jesper Dangaard Brouer's avatar
    page_pool: refurbish version of page_pool code · ff7d6b27
    Jesper Dangaard Brouer authored
    Need a fast page recycle mechanism for ndo_xdp_xmit API for returning
    pages on DMA-TX completion time, which have good cross CPU
    performance, given DMA-TX completion time can happen on a remote CPU.
    
    Refurbish my page_pool code, that was presented[1] at MM-summit 2016.
    Adapted page_pool code to not depend the page allocator and
    integration into struct page.  The DMA mapping feature is kept,
    even-though it will not be activated/used in this patchset.
    
    [1] http://people.netfilter.org/hawk/presentations/MM-summit2016/generic_page_pool_mm_summit2016.pdf
    
    V2: Adjustments requested by Tariq
     - Changed page_pool_create return codes, don't return NULL, only
       ERR_PTR, as this simplifies err handling in drivers.
    
    V4: many small improvements and cleanups
    - Add DOC comment section, that can be used by kernel-doc
    - Improve fallback mode, to work better with refcnt based recycling
      e.g. remove a WARN as pointed out by Tariq
      e.g. quicker fallback if ptr_ring is empty.
    
    V5: Fixed SPDX license as pointed out by Alexei
    
    V6: Adjustments requested by Eric Dumazet
     - Adjust ____cacheline_aligned_in_smp usage/placement
     - Move rcu_head in struct page_pool
     - Free pages quicker on destroy, minimize resources delayed an RCU period
     - Remove code for forward/backward compat ABI interface
    
    V8: Issues found by kbuild test robot
     - Address sparse should be static warnings
     - Only compile+link when a driver use/select page_pool,
       mlx5 selects CONFIG_PAGE_POOL, although its first used in two patches
    Signed-off-by: default avatarJesper Dangaard Brouer <brouer@redhat.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    ff7d6b27
Kconfig 13.2 KB