diff options
Diffstat (limited to '5eb51caa-sched-vcpu-pause-flags-atomic.patch')
| -rw-r--r-- | 5eb51caa-sched-vcpu-pause-flags-atomic.patch | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/5eb51caa-sched-vcpu-pause-flags-atomic.patch b/5eb51caa-sched-vcpu-pause-flags-atomic.patch new file mode 100644 index 0000000..848b593 --- /dev/null +++ b/5eb51caa-sched-vcpu-pause-flags-atomic.patch @@ -0,0 +1,76 @@ +# Commit e0d92d9bd7997c6bcda17a19aba4f3957dd1a2e9 +# Date 2020-05-08 10:47:38 +0200 +# Author Juergen Gross <jgross@suse.com> +# Committer Jan Beulich <jbeulich@suse.com> +sched: always modify vcpu pause flags atomically + +credit2 is currently modifying the pause flags of vcpus non-atomically +via sched_set_pause_flags() and sched_clear_pause_flags(). This is +dangerous as there are cases where the paus flags are modified without +any lock held. + +So drop the non-atomic pause flag modification functions and rename the +atomic ones dropping the _atomic suffix. + +Fixes: a76255b4266516 ("xen/sched: make credit2 scheduler vcpu agnostic.") +Signed-off-by: Juergen Gross <jgross@suse.com> +Reviewed-by: Dario Faggioli <dfaggioli@suse.com> + +--- a/xen/common/sched_credit.c ++++ b/xen/common/sched_credit.c +@@ -452,7 +452,7 @@ static inline void __runq_tickle(struct + SCHED_UNIT_STAT_CRANK(cur, kicked_away); + SCHED_UNIT_STAT_CRANK(cur, migrate_r); + SCHED_STAT_CRANK(migrate_kicked_away); +- sched_set_pause_flags_atomic(cur->unit, _VPF_migrating); ++ sched_set_pause_flags(cur->unit, _VPF_migrating); + } + /* Tickle cpu anyway, to let new preempt cur. */ + SCHED_STAT_CRANK(tickled_busy_cpu); +@@ -983,7 +983,7 @@ csched_unit_acct(struct csched_private * + { + SCHED_UNIT_STAT_CRANK(svc, migrate_r); + SCHED_STAT_CRANK(migrate_running); +- sched_set_pause_flags_atomic(currunit, _VPF_migrating); ++ sched_set_pause_flags(currunit, _VPF_migrating); + /* + * As we are about to tickle cpu, we should clear its bit in + * idlers. But, if we are here, it means there is someone running +--- a/xen/include/xen/sched-if.h ++++ b/xen/include/xen/sched-if.h +@@ -175,7 +175,7 @@ static inline void sched_set_pause_flags + struct vcpu *v; + + for_each_sched_unit_vcpu ( unit, v ) +- __set_bit(bit, &v->pause_flags); ++ set_bit(bit, &v->pause_flags); + } + + /* Clear a bit in pause_flags of all vcpus of a unit. */ +@@ -184,26 +184,6 @@ static inline void sched_clear_pause_fla + { + struct vcpu *v; + +- for_each_sched_unit_vcpu ( unit, v ) +- __clear_bit(bit, &v->pause_flags); +-} +- +-/* Set a bit in pause_flags of all vcpus of a unit via atomic updates. */ +-static inline void sched_set_pause_flags_atomic(struct sched_unit *unit, +- unsigned int bit) +-{ +- struct vcpu *v; +- +- for_each_sched_unit_vcpu ( unit, v ) +- set_bit(bit, &v->pause_flags); +-} +- +-/* Clear a bit in pause_flags of all vcpus of a unit via atomic updates. */ +-static inline void sched_clear_pause_flags_atomic(struct sched_unit *unit, +- unsigned int bit) +-{ +- struct vcpu *v; +- + for_each_sched_unit_vcpu ( unit, v ) + clear_bit(bit, &v->pause_flags); + } |