lkml.org 
[lkml]   [2017]   [Apr]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectQuestion on ___GFP_NOLOCKDEP - Was: Re: [PATCH 1/1] Remove hardcoding of ___GFP_xxx bitmasks
    From
    Date
    On 26/04/17 18:29, Igor Stoppa wrote:

    > On 26/04/17 17:47, Michal Hocko wrote:

    [...]

    >> Also the current mm tree has ___GFP_NOLOCKDEP which is not addressed
    >> here so I suspect you have based your change on the Linus tree.

    > I used your tree from kernel.org

    I found it, I was using master, instead of auto-latest (is it correct?)
    But now I see something that I do not understand (apologies if I'm
    asking something obvious).

    First there is:

    [...]
    #define ___GFP_WRITE 0x800000u
    #define ___GFP_KSWAPD_RECLAIM 0x1000000u
    #ifdef CONFIG_LOCKDEP
    #define ___GFP_NOLOCKDEP 0x4000000u
    #else
    #define ___GFP_NOLOCKDEP 0
    #endif

    Then:

    /* Room for N __GFP_FOO bits */
    #define __GFP_BITS_SHIFT (25 + IS_ENABLED(CONFIG_LOCKDEP))



    Shouldn't it be either:
    ___GFP_NOLOCKDEP 0x2000000u

    or:

    #define __GFP_BITS_SHIFT (25 + 2 * IS_ENABLED(CONFIG_LOCKDEP))


    thanks, igor

    \
     
     \ /
      Last update: 2017-04-27 14:18    [W:2.835 / U:0.984 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site