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powerpc/pseries: Do not save the previous DTL mask value 

When CONFIG_VIRT_CPU_ACCOUNTING_NATIVE is enabled, we always initialize
DTL enable mask to DTL_LOG_PREEMPT (0x2). There are no other places
where the mask is changed. As such, when reading the DTL log buffer
through debugfs, there is no need to save and restore the previous mask
value.

We don't need to save and restore the earlier mask value if
CONFIG_VIRT_CPU_ACCOUNTING_NATIVE is not enabled. So, remove the field
from the structure as well.

Acked-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Naveen N. Rao 2019-07-03 22:33:55 +05:30 committed by Michael Ellerman
parent 515bbc8ab4
commit 5b3306f084
1 changed files with 1 additions and 3 deletions
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4
arch/powerpc/platforms/pseries/dtl.c
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@ -55,7 +55,6 @@ struct dtl_ring {
struct dtl_entry *write_ptr;
struct dtl_entry *buf;
struct dtl_entry *buf_end;
u8 saved_dtl_mask;
};
static DEFINE_PER_CPU(struct dtl_ring, dtl_rings);
@ -105,7 +104,6 @@ static int dtl_start(struct dtl *dtl)
dtlr->write_ptr = dtl->buf;
/* enable event logging */
dtlr->saved_dtl_mask = lppaca_of(dtl->cpu).dtl_enable_mask;
lppaca_of(dtl->cpu).dtl_enable_mask |= dtl_event_mask;
dtl_consumer = consume_dtle;
@ -123,7 +121,7 @@ static void dtl_stop(struct dtl *dtl)
dtlr->buf = NULL;
/* restore dtl_enable_mask */
lppaca_of(dtl->cpu).dtl_enable_mask = dtlr->saved_dtl_mask;
lppaca_of(dtl->cpu).dtl_enable_mask = DTL_LOG_PREEMPT;
if (atomic_dec_and_test(&dtl_count))
dtl_consumer = NULL;