• Jaewon Kim's avatar
    mm: cma: print allocation failure reason and bitmap status · dbe43d4d
    Jaewon Kim authored
    There are many reasons of CMA allocation failure such as EBUSY, ENOMEM,
    EINTR.  But we did not know error reason so far.  This patch prints the
    error value.
    
    Additionally if CONFIG_CMA_DEBUG is enabled, this patch shows bitmap
    status to know available pages.  Actually CMA internally tries on all
    available regions because some regions can be failed because of EBUSY.
    Bitmap status is useful to know in detail on both ENONEM and EBUSY;
    
     ENOMEM: not tried at all because of no available region
             it could be too small total region or could be fragmentation issue
     EBUSY:  tried some region but all failed
    
    This is an ENOMEM example with this patch.
    
        [2:   Binder:714_1:  744] cma: cma_alloc: alloc failed, req-size: 256 pages, ret: -12
    
    If CONFIG_CMA_DEBUG is enabled, avabile pages also will be shown as
    concatenated size@position format.  So 4@572 means that there are 4
    available pages at 572 position starting from 0 position.
    
        [2:   Binder:714_1:  744] cma: number of available pages: 4@572+7@585+7@601+8@632+38@730+166@1114+127@1921=> 357 free of 2048 total pages
    
    Link: http://lkml.kernel.org/r/1485909785-3952-1-git-send-email-jaewon31.kim@samsung.comSigned-off-by: default avatarJaewon Kim <jaewon31.kim@samsung.com>
    Acked-by: default avatarMichal Nazarewicz <mina86@mina86.com>
    Cc: Laura Abbott <labbott@redhat.com>
    Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    dbe43d4d
cma.c 13 KB