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    • /[pkg-src]/trunk/kernel26-magellan/patches-2.6.21-r4/0007-2.6.21-sched-limit_policy_changes.patch

    Contents of /trunk/kernel26-magellan/patches-2.6.21-r4/0007-2.6.21-sched-limit_policy_changes.patch

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    Revision 222 - (show annotations) (download)
    Tue Jun 12 08:03:28 2007 UTC (16 years, 10 months ago) by niro
    File size: 1532 byte(s) 
    files for 2.6.21-magellan-r4
    1 Many applications explicitly set SCHED_NORMAL on threads thus undoing the
    2 usefulness of the SCHED_ISO, SCHED_BATCH and SCHED_IDLEPRIO policies.
    3
    4 For unprivileged users:
    5
    6 Only allow non realtime policies to be downgraded from ISO->BATCH->IDLEPRIO
    7 but not back to NORMAL.
    8
    9 Signed-off-by: Con Kolivas <kernel@kolivas.org>
    10
    11 ---
    12 kernel/sched.c | 26 ++++++++++++++++++++++++++
    13 1 file changed, 26 insertions(+)
    14
    15 Index: linux-2.6.21-ck2/kernel/sched.c
    16 ===================================================================
    17 --- linux-2.6.21-ck2.orig/kernel/sched.c 2007-05-14 19:30:31.000000000 +1000
    18 +++ linux-2.6.21-ck2/kernel/sched.c 2007-05-14 19:30:31.000000000 +1000
    19 @@ -4295,6 +4295,31 @@ recheck:
    20 if (param->sched_priority > p->rt_priority &&
    21 param->sched_priority > rlim_rtprio)
    22 return -EPERM;
    23 + } else {
    24 + switch (p->policy) {
    25 + /*
    26 + * Can only downgrade policies but not back to
    27 + * SCHED_NORMAL
    28 + */
    29 + case SCHED_ISO:
    30 + if (policy == SCHED_ISO)
    31 + goto out;
    32 + if (policy == SCHED_NORMAL)
    33 + return -EPERM;
    34 + break;
    35 + case SCHED_BATCH:
    36 + if (policy == SCHED_BATCH)
    37 + goto out;
    38 + if (policy != SCHED_IDLEPRIO)
    39 + return -EPERM;
    40 + break;
    41 + case SCHED_IDLEPRIO:
    42 + if (policy == SCHED_IDLEPRIO)
    43 + goto out;
    44 + return -EPERM;
    45 + default:
    46 + break;
    47 + }
    48 }
    49
    50 /* can't change other user's priorities */
    51 @@ -4351,6 +4376,7 @@ recheck:
    52
    53 rt_mutex_adjust_pi(p);
    54
    55 +out:
    56 return 0;
    57 }
    58 EXPORT_SYMBOL_GPL(sched_setscheduler);