perf/core: Drop PERF_EVENT_TXN

We currently use PERF_EVENT_TXN flag to determine if we are in the middle
of a transaction. If in a transaction, we defer the schedulability checks
from pmu->add() operation to the pmu->commit() operation.

Now that we have "transaction types" (PERF_PMU_TXN_ADD, PERF_PMU_TXN_READ)
we can use the type to determine if we are in a transaction and drop the
PERF_EVENT_TXN flag.

When PERF_EVENT_TXN is dropped, the cpuhw->group_flag on some architectures
becomes unused, so drop that field as well.

This is an extension of the Powerpc patch from Peter Zijlstra to s390,
Sparc and x86 architectures.

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1441336073-22750-11-git-send-email-sukadev@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
index c84074185c80b53eb868e47a27b386feab3b8df1..d1e65ce545b31f427629853a3803a6b0b4af0d9b 100644 (file)
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -48,7 +48,6 @@ struct cpu_hw_events {
        unsigned long amasks[MAX_HWEVENTS][MAX_EVENT_ALTERNATIVES];
        unsigned long avalues[MAX_HWEVENTS][MAX_EVENT_ALTERNATIVES];
 
-       unsigned int group_flag;
        unsigned int txn_flags;
        int n_txn_start;
 
@@ -1442,7 +1441,7 @@ static int power_pmu_add(struct perf_event *event, int ef_flags)
         * skip the schedulability test here, it will be performed
         * at commit time(->commit_txn) as a whole
         */
-       if (cpuhw->group_flag & PERF_EVENT_TXN)
+       if (cpuhw->txn_flags & PERF_PMU_TXN_ADD)
                goto nocheck;
 
        if (check_excludes(cpuhw->event, cpuhw->flags, n0, 1))
@@ -1603,7 +1602,6 @@ static void power_pmu_start_txn(struct pmu *pmu, unsigned int txn_flags)
                return;
 
        perf_pmu_disable(pmu);
-       cpuhw->group_flag |= PERF_EVENT_TXN;
        cpuhw->n_txn_start = cpuhw->n_events;
 }
 
@@ -1624,7 +1622,6 @@ static void power_pmu_cancel_txn(struct pmu *pmu)
        if (txn_flags & ~PERF_PMU_TXN_ADD)
                return;
 
-       cpuhw->group_flag &= ~PERF_EVENT_TXN;
        perf_pmu_enable(pmu);
 }
 
@@ -1659,7 +1656,6 @@ static int power_pmu_commit_txn(struct pmu *pmu)
        for (i = cpuhw->n_txn_start; i < n; ++i)
                cpuhw->event[i]->hw.config = cpuhw->events[i];
 
-       cpuhw->group_flag &= ~PERF_EVENT_TXN;
        cpuhw->txn_flags = 0;
        perf_pmu_enable(pmu);
        return 0;

diff --git a/arch/s390/kernel/perf_cpum_cf.c b/arch/s390/kernel/perf_cpum_cf.c
index 19138be412d63d51f7a9c9a0026fad2c8d78f126..cb774ff6e749070cefc5250fddfb45bf8d4c260d 100644 (file)
--- a/arch/s390/kernel/perf_cpum_cf.c
+++ b/arch/s390/kernel/perf_cpum_cf.c
@@ -536,7 +536,7 @@ static int cpumf_pmu_add(struct perf_event *event, int flags)
         * For group events transaction, the authorization check is
         * done in cpumf_pmu_commit_txn().
         */
-       if (!(cpuhw->flags & PERF_EVENT_TXN))
+       if (!(cpuhw->txn_flags & PERF_PMU_TXN_ADD))
                if (validate_ctr_auth(&event->hw))
                        return -EPERM;
 
@@ -590,7 +590,6 @@ static void cpumf_pmu_start_txn(struct pmu *pmu, unsigned int txn_flags)
                return;
 
        perf_pmu_disable(pmu);
-       cpuhw->flags |= PERF_EVENT_TXN;
        cpuhw->tx_state = cpuhw->state;
 }
 
@@ -613,7 +612,6 @@ static void cpumf_pmu_cancel_txn(struct pmu *pmu)
 
        WARN_ON(cpuhw->tx_state != cpuhw->state);
 
-       cpuhw->flags &= ~PERF_EVENT_TXN;
        perf_pmu_enable(pmu);
 }
 
@@ -640,7 +638,6 @@ static int cpumf_pmu_commit_txn(struct pmu *pmu)
        if ((state & cpuhw->info.auth_ctl) != state)
                return -EPERM;
 
-       cpuhw->flags &= ~PERF_EVENT_TXN;
        cpuhw->txn_flags = 0;
        perf_pmu_enable(pmu);
        return 0;

diff --git a/arch/sparc/kernel/perf_event.c b/arch/sparc/kernel/perf_event.c
index 2c0984d146ec97a8a921a2b6d6f32bebec912e84..b0da5aedb336c643baf9163c010c6c679ce6bbdc 100644 (file)
--- a/arch/sparc/kernel/perf_event.c
+++ b/arch/sparc/kernel/perf_event.c
@@ -108,7 +108,6 @@ struct cpu_hw_events {
        /* Enabled/disable state.  */
        int                     enabled;
 
-       unsigned int            group_flag;
        unsigned int            txn_flags;
 };
 static DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events) = { .enabled = 1, };
@@ -1380,7 +1379,7 @@ static int sparc_pmu_add(struct perf_event *event, int ef_flags)
         * skip the schedulability test here, it will be performed
         * at commit time(->commit_txn) as a whole
         */
-       if (cpuc->group_flag & PERF_EVENT_TXN)
+       if (cpuc->txn_flags & PERF_PMU_TXN_ADD)
                goto nocheck;
 
        if (check_excludes(cpuc->event, n0, 1))
@@ -1506,7 +1505,6 @@ static void sparc_pmu_start_txn(struct pmu *pmu, unsigned int txn_flags)
                return;
 
        perf_pmu_disable(pmu);
-       cpuhw->group_flag |= PERF_EVENT_TXN;
 }
 
 /*
@@ -1526,7 +1524,6 @@ static void sparc_pmu_cancel_txn(struct pmu *pmu)
        if (txn_flags & ~PERF_PMU_TXN_ADD)
                return;
 
-       cpuhw->group_flag &= ~PERF_EVENT_TXN;
        perf_pmu_enable(pmu);
 }
 
@@ -1556,7 +1553,6 @@ static int sparc_pmu_commit_txn(struct pmu *pmu)
        if (sparc_check_constraints(cpuc->event, cpuc->events, n))
                return -EAGAIN;
 
-       cpuc->group_flag &= ~PERF_EVENT_TXN;
        cpuc->txn_flags = 0;
        perf_pmu_enable(pmu);
        return 0;

diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index dc77ef470e0e246ce38df93d14176d65f0c1d5bb..4562cf070c279d5edeb0e18ae94c8bff94166dd8 100644 (file)
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -1175,7 +1175,7 @@ static int x86_pmu_add(struct perf_event *event, int flags)
         * skip the schedulability test here, it will be performed
         * at commit time (->commit_txn) as a whole.
         */
-       if (cpuc->group_flag & PERF_EVENT_TXN)
+       if (cpuc->txn_flags & PERF_PMU_TXN_ADD)
                goto done_collect;
 
        ret = x86_pmu.schedule_events(cpuc, n, assign);
@@ -1326,7 +1326,7 @@ static void x86_pmu_del(struct perf_event *event, int flags)
         * XXX assumes any ->del() called during a TXN will only be on
         * an event added during that same TXN.
         */
-       if (cpuc->group_flag & PERF_EVENT_TXN)
+       if (cpuc->txn_flags & PERF_PMU_TXN_ADD)
                return;
 
        /*
@@ -1764,7 +1764,6 @@ static void x86_pmu_start_txn(struct pmu *pmu, unsigned int txn_flags)
                return;
 
        perf_pmu_disable(pmu);
-       __this_cpu_or(cpu_hw_events.group_flag, PERF_EVENT_TXN);
        __this_cpu_write(cpu_hw_events.n_txn, 0);
 }
 
@@ -1785,7 +1784,6 @@ static void x86_pmu_cancel_txn(struct pmu *pmu)
        if (txn_flags & ~PERF_PMU_TXN_ADD)
                return;
 
-       __this_cpu_and(cpu_hw_events.group_flag, ~PERF_EVENT_TXN);
        /*
         * Truncate collected array by the number of events added in this
         * transaction. See x86_pmu_add() and x86_pmu_*_txn().
@@ -1830,7 +1828,6 @@ static int x86_pmu_commit_txn(struct pmu *pmu)
         */
        memcpy(cpuc->assign, assign, n*sizeof(int));
 
-       cpuc->group_flag &= ~PERF_EVENT_TXN;
        cpuc->txn_flags = 0;
        perf_pmu_enable(pmu);
        return 0;

diff --git a/arch/x86/kernel/cpu/perf_event.h b/arch/x86/kernel/cpu/perf_event.h
index c99c93b9e348edfaf5ec3800f3433958e3daf44e..953a0e4e3284f1c6612930383253bdc7d372e04a 100644 (file)
--- a/arch/x86/kernel/cpu/perf_event.h
+++ b/arch/x86/kernel/cpu/perf_event.h
@@ -195,7 +195,6 @@ struct cpu_hw_events {
 
        int                     n_excl; /* the number of exclusive events */
 
-       unsigned int            group_flag;
        unsigned int            txn_flags;
        int                     is_fake;
 

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index b83cea932f74f67d0c904a618e7f8f5535b35010..d841d33bcdc9c370742db6408e1f979594d37099 100644 (file)
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -199,8 +199,6 @@ struct perf_event;
 /*
  * Common implementation detail of pmu::{start,commit,cancel}_txn
  */
-#define PERF_EVENT_TXN 0x1
-
 #define PERF_PMU_TXN_ADD  0x1          /* txn to add/schedule event on PMU */
 #define PERF_PMU_TXN_READ 0x2          /* txn to read event group from PMU */