Re: svn commit: r358483 - head/sys/compat/linux
On Thu, 5 Mar 2020 16:15:10 +0300 Yuri Pankov
wrote:
> Tijl Coosemans wrote:
>> Author: tijl
>> Date: Sun Mar 1 13:12:04 2020
>> New Revision: 358483
>> URL: https://svnweb.freebsd.org/changeset/base/358483
>>
>> Log:
>>linuxulator: Map scheduler priorities to Linux priorities.
>>
>>On Linux the valid range of priorities for the SCHED_FIFO and SCHED_RR
>>scheduling policies is [1,99]. For SCHED_OTHER the single valid priority
>> is
>>0. On FreeBSD it is [0,31] for all policies. Programs are supposed to
>>query the valid range using sched_get_priority_(min|max), but of course
>> some
>>programs assume the Linux values are valid.
>>
>>This commit adds a tunable compat.linux.map_sched_prio. When enabled
>>sched_get_priority_(min|max) return the Linux values and
>> sched_setscheduler
>>and sched_(get|set)param translate between FreeBSD and Linux values.
>>
>>Because there are more Linux levels than FreeBSD levels, multiple Linux
>>levels map to a single FreeBSD level, which means pre-emption might not
>>happen as it does on Linux, so the tunable allows to disable this
>> behaviour.
>>It is enabled by default because I think it is unlikely that anyone runs
>>real-time software under Linux emulation on FreeBSD that critically relies
>>on correct pre-emption.
>>
>>This fixes FMOD, a commercial sound library used by several games.
>>
>>PR: 240043
>>Tested by:Alex S
>>Reviewed by: dchagin
>>MFC after:2 weeks
>>Differential Revision:https://reviews.freebsd.org/D23790
>>
>> Modified:
>>head/sys/compat/linux/linux_misc.c
>>head/sys/compat/linux/linux_misc.h
>>
>> Modified: head/sys/compat/linux/linux_misc.c
>> ==
>> --- head/sys/compat/linux/linux_misc.c Sun Mar 1 12:34:27 2020
>> (r358482)
>> +++ head/sys/compat/linux/linux_misc.c Sun Mar 1 13:12:04 2020
>> (r358483)
>> @@ -144,6 +144,11 @@ struct l_pselect6arg {
>> l_size_tss_len;
>> };
>>
>> +static bool map_sched_prio = true;
>> +SYSCTL_BOOL(_compat_linux, OID_AUTO, map_sched_prio, CTLFLAG_RDTUN,
>> +&map_sched_prio, 0, "Map scheduler priorities to Linux priorities "
>> +"(not POSIX compliant)");
>
> I'm seeing the following in the log:
>
> sysctl_warn_reuse: can't re-use a leaf (compat.linux.map_sched_prio)!
>
> Should this be done for both linux and linux32 (when one exists) or made
> to install one time only?
Ah, thanks for the report, I've moved it to linux_common in r358673.
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Re: svn commit: r358483 - head/sys/compat/linux
Tijl Coosemans wrote:
Author: tijl
Date: Sun Mar 1 13:12:04 2020
New Revision: 358483
URL: https://svnweb.freebsd.org/changeset/base/358483
Log:
linuxulator: Map scheduler priorities to Linux priorities.
On Linux the valid range of priorities for the SCHED_FIFO and SCHED_RR
scheduling policies is [1,99]. For SCHED_OTHER the single valid priority is
0. On FreeBSD it is [0,31] for all policies. Programs are supposed to
query the valid range using sched_get_priority_(min|max), but of course some
programs assume the Linux values are valid.
This commit adds a tunable compat.linux.map_sched_prio. When enabled
sched_get_priority_(min|max) return the Linux values and sched_setscheduler
and sched_(get|set)param translate between FreeBSD and Linux values.
Because there are more Linux levels than FreeBSD levels, multiple Linux
levels map to a single FreeBSD level, which means pre-emption might not
happen as it does on Linux, so the tunable allows to disable this behaviour.
It is enabled by default because I think it is unlikely that anyone runs
real-time software under Linux emulation on FreeBSD that critically relies
on correct pre-emption.
This fixes FMOD, a commercial sound library used by several games.
PR: 240043
Tested by: Alex S
Reviewed by: dchagin
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D23790
Modified:
head/sys/compat/linux/linux_misc.c
head/sys/compat/linux/linux_misc.h
Modified: head/sys/compat/linux/linux_misc.c
==
--- head/sys/compat/linux/linux_misc.c Sun Mar 1 12:34:27 2020
(r358482)
+++ head/sys/compat/linux/linux_misc.c Sun Mar 1 13:12:04 2020
(r358483)
@@ -144,6 +144,11 @@ struct l_pselect6arg {
l_size_tss_len;
};
+static bool map_sched_prio = true;
+SYSCTL_BOOL(_compat_linux, OID_AUTO, map_sched_prio, CTLFLAG_RDTUN,
+&map_sched_prio, 0, "Map scheduler priorities to Linux priorities "
+"(not POSIX compliant)");
I'm seeing the following in the log:
sysctl_warn_reuse: can't re-use a leaf (compat.linux.map_sched_prio)!
Should this be done for both linux and linux32 (when one exists) or made
to install one time only?
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svn commit: r358483 - head/sys/compat/linux
Author: tijl
Date: Sun Mar 1 13:12:04 2020
New Revision: 358483
URL: https://svnweb.freebsd.org/changeset/base/358483
Log:
linuxulator: Map scheduler priorities to Linux priorities.
On Linux the valid range of priorities for the SCHED_FIFO and SCHED_RR
scheduling policies is [1,99]. For SCHED_OTHER the single valid priority is
0. On FreeBSD it is [0,31] for all policies. Programs are supposed to
query the valid range using sched_get_priority_(min|max), but of course some
programs assume the Linux values are valid.
This commit adds a tunable compat.linux.map_sched_prio. When enabled
sched_get_priority_(min|max) return the Linux values and sched_setscheduler
and sched_(get|set)param translate between FreeBSD and Linux values.
Because there are more Linux levels than FreeBSD levels, multiple Linux
levels map to a single FreeBSD level, which means pre-emption might not
happen as it does on Linux, so the tunable allows to disable this behaviour.
It is enabled by default because I think it is unlikely that anyone runs
real-time software under Linux emulation on FreeBSD that critically relies
on correct pre-emption.
This fixes FMOD, a commercial sound library used by several games.
PR: 240043
Tested by:Alex S
Reviewed by: dchagin
MFC after:2 weeks
Differential Revision:https://reviews.freebsd.org/D23790
Modified:
head/sys/compat/linux/linux_misc.c
head/sys/compat/linux/linux_misc.h
Modified: head/sys/compat/linux/linux_misc.c
==
--- head/sys/compat/linux/linux_misc.c Sun Mar 1 12:34:27 2020
(r358482)
+++ head/sys/compat/linux/linux_misc.c Sun Mar 1 13:12:04 2020
(r358483)
@@ -144,6 +144,11 @@ struct l_pselect6arg {
l_size_tss_len;
};
+static bool map_sched_prio = true;
+SYSCTL_BOOL(_compat_linux, OID_AUTO, map_sched_prio, CTLFLAG_RDTUN,
+&map_sched_prio, 0, "Map scheduler priorities to Linux priorities "
+"(not POSIX compliant)");
+
static int linux_utimensat_nsec_valid(l_long);
@@ -1419,6 +1424,33 @@ linux_sched_setscheduler(struct thread *td,
if (error)
return (error);
+ if (map_sched_prio) {
+ switch (policy) {
+ case SCHED_OTHER:
+ if (sched_param.sched_priority != 0)
+ return (EINVAL);
+
+ sched_param.sched_priority =
+ PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE;
+ break;
+ case SCHED_FIFO:
+ case SCHED_RR:
+ if (sched_param.sched_priority < 1 ||
+ sched_param.sched_priority >= LINUX_MAX_RT_PRIO)
+ return (EINVAL);
+
+ /*
+* Map [1, LINUX_MAX_RT_PRIO - 1] to
+* [0, RTP_PRIO_MAX - RTP_PRIO_MIN] (rounding down).
+*/
+ sched_param.sched_priority =
+ (sched_param.sched_priority - 1) *
+ (RTP_PRIO_MAX - RTP_PRIO_MIN + 1) /
+ (LINUX_MAX_RT_PRIO - 1);
+ break;
+ }
+ }
+
tdt = linux_tdfind(td, args->pid, -1);
if (tdt == NULL)
return (ESRCH);
@@ -1462,6 +1494,20 @@ linux_sched_get_priority_max(struct thread *td,
{
struct sched_get_priority_max_args bsd;
+ if (map_sched_prio) {
+ switch (args->policy) {
+ case LINUX_SCHED_OTHER:
+ td->td_retval[0] = 0;
+ return (0);
+ case LINUX_SCHED_FIFO:
+ case LINUX_SCHED_RR:
+ td->td_retval[0] = LINUX_MAX_RT_PRIO - 1;
+ return (0);
+ default:
+ return (EINVAL);
+ }
+ }
+
switch (args->policy) {
case LINUX_SCHED_OTHER:
bsd.policy = SCHED_OTHER;
@@ -1484,6 +1530,20 @@ linux_sched_get_priority_min(struct thread *td,
{
struct sched_get_priority_min_args bsd;
+ if (map_sched_prio) {
+ switch (args->policy) {
+ case LINUX_SCHED_OTHER:
+ td->td_retval[0] = 0;
+ return (0);
+ case LINUX_SCHED_FIFO:
+ case LINUX_SCHED_RR:
+ td->td_retval[0] = 1;
+ return (0);
+ default:
+ return (EINVAL);
+ }
+ }
+
switch (args->policy) {
case LINUX_SCHED_OTHER:
bsd.policy = SCHED_OTHER;
@@ -1864,7 +1924,7 @@ linux_sched_setparam(struct thread *td,
{
struct sched_param sched_param;
struct thread *tdt;
- int error;
+ int err
