• Hugh Dickins's avatar
    mm: raise MemFree by reverting percpu_pagelist_fraction to 0 · 1b76b02f
    Hugh Dickins authored
    Why is there less MemFree than there used to be?  It perturbed a test,
    so I've just been bisecting linux-next, and now find the offender went
    upstream yesterday.
    Commit 93278814
     "mm: fix division by 0 in percpu_pagelist_fraction()"
    mistakenly initialized percpu_pagelist_fraction to the sysctl's minimum 8,
    which leaves 1/8th of memory on percpu lists (on each cpu??); but most of
    us expect it to be left unset at 0 (and it's not then used as a divisor).
      MemTotal: 8061476kB  8061476kB  8061476kB  8061476kB  8061476kB  8061476kB
      Repetitive test with percpu_pagelist_fraction 8:
      MemFree:  6948420kB  6237172kB  6949696kB  6840692kB  6949048kB  6862984kB
      Same test with percpu_pagelist_fraction back to 0:
      MemFree:  7945000kB  7944908kB  7948568kB  7949060kB  7948796kB  7948812kB
    Signed-off-by: default avatarHugh Dickins <hughd@google.com>
    [ We really should fix the crazy sysctl interface too, but that's a
      separate thing - Linus ]
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
page_alloc.c 157 KB