lkml.org 
[lkml]   [2008]   [Apr]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH] xfs: reduce stack usage in xfs_bmap_btalloc()
    Denys Vlasenko wrote:
    > Hi David,
    >
    > This patch reduces xfs_bmap_btalloc() stack usage by 50 bytes
    > by moving part of its body into a helper function.
    >
    > This results in some variables not taking stack space in
    > xfs_bmap_btalloc() anymore.
    >
    > The helper itself does not call anything stack-deep.
    > Stack-deep call to xfs_alloc_vextent() happen
    > in xfs_bmap_btalloc(), as before.
    >
    > Compile tested only.
    >
    > Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
    > --
    > vda
    >

    Looks like a very good approach, it pushes a lot of large local vars off
    into the helper.

    There is one build-time problem if DEBUG is turned on:

    if (args.fsbno != NULLFSBLOCK) {
    ap->firstblock = ap->rval = args.fsbno;
    ASSERT(nullfb || fb_agno == args.agno ||
    (ap->low && fb_agno < args.agno));

    in xfs_bmap_btalloc, which no longer has an fb_agno variable which the
    ASSERT macro uses.

    Thanks,

    -Eric


    \
     
     \ /
      Last update: 2008-04-26 20:57    [W:0.023 / U:128.052 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site