percpu: add tracepoint support for percpu memory

Add support for tracepoints to the following events: chunk allocation,
chunk free, area allocation, area free, and area allocation failure.
This should let us replay percpu memory requests and evaluate
corresponding decisions.

Signed-off-by: Dennis Zhou <dennisz@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Dennis Zhou 2017-06-19 19:28:32 -04:00 committed by Tejun Heo
parent 30a5b5367e
commit df95e795a7
4 changed files with 141 additions and 0 deletions

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@ -0,0 +1,125 @@
#undef TRACE_SYSTEM
#define TRACE_SYSTEM percpu
#if !defined(_TRACE_PERCPU_H) || defined(TRACE_HEADER_MULTI_READ)
#define _TRACE_PERCPU_H
#include <linux/tracepoint.h>
TRACE_EVENT(percpu_alloc_percpu,
TP_PROTO(bool reserved, bool is_atomic, size_t size,
size_t align, void *base_addr, int off, void __percpu *ptr),
TP_ARGS(reserved, is_atomic, size, align, base_addr, off, ptr),
TP_STRUCT__entry(
__field( bool, reserved )
__field( bool, is_atomic )
__field( size_t, size )
__field( size_t, align )
__field( void *, base_addr )
__field( int, off )
__field( void __percpu *, ptr )
),
TP_fast_assign(
__entry->reserved = reserved;
__entry->is_atomic = is_atomic;
__entry->size = size;
__entry->align = align;
__entry->base_addr = base_addr;
__entry->off = off;
__entry->ptr = ptr;
),
TP_printk("reserved=%d is_atomic=%d size=%zu align=%zu base_addr=%p off=%d ptr=%p",
__entry->reserved, __entry->is_atomic,
__entry->size, __entry->align,
__entry->base_addr, __entry->off, __entry->ptr)
);
TRACE_EVENT(percpu_free_percpu,
TP_PROTO(void *base_addr, int off, void __percpu *ptr),
TP_ARGS(base_addr, off, ptr),
TP_STRUCT__entry(
__field( void *, base_addr )
__field( int, off )
__field( void __percpu *, ptr )
),
TP_fast_assign(
__entry->base_addr = base_addr;
__entry->off = off;
__entry->ptr = ptr;
),
TP_printk("base_addr=%p off=%d ptr=%p",
__entry->base_addr, __entry->off, __entry->ptr)
);
TRACE_EVENT(percpu_alloc_percpu_fail,
TP_PROTO(bool reserved, bool is_atomic, size_t size, size_t align),
TP_ARGS(reserved, is_atomic, size, align),
TP_STRUCT__entry(
__field( bool, reserved )
__field( bool, is_atomic )
__field( size_t, size )
__field( size_t, align )
),
TP_fast_assign(
__entry->reserved = reserved;
__entry->is_atomic = is_atomic;
__entry->size = size;
__entry->align = align;
),
TP_printk("reserved=%d is_atomic=%d size=%zu align=%zu",
__entry->reserved, __entry->is_atomic,
__entry->size, __entry->align)
);
TRACE_EVENT(percpu_create_chunk,
TP_PROTO(void *base_addr),
TP_ARGS(base_addr),
TP_STRUCT__entry(
__field( void *, base_addr )
),
TP_fast_assign(
__entry->base_addr = base_addr;
),
TP_printk("base_addr=%p", __entry->base_addr)
);
TRACE_EVENT(percpu_destroy_chunk,
TP_PROTO(void *base_addr),
TP_ARGS(base_addr),
TP_STRUCT__entry(
__field( void *, base_addr )
),
TP_fast_assign(
__entry->base_addr = base_addr;
),
TP_printk("base_addr=%p", __entry->base_addr)
);
#endif /* _TRACE_PERCPU_H */
#include <trace/define_trace.h>

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@ -73,6 +73,7 @@ static struct pcpu_chunk *pcpu_create_chunk(void)
spin_unlock_irq(&pcpu_lock);
pcpu_stats_chunk_alloc();
trace_percpu_create_chunk(chunk->base_addr);
return chunk;
}
@ -82,6 +83,7 @@ static void pcpu_destroy_chunk(struct pcpu_chunk *chunk)
const int nr_pages = pcpu_group_sizes[0] >> PAGE_SHIFT;
pcpu_stats_chunk_dealloc();
trace_percpu_destroy_chunk(chunk->base_addr);
if (chunk && chunk->data)
__free_pages(chunk->data, order_base_2(nr_pages));

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@ -345,6 +345,7 @@ static struct pcpu_chunk *pcpu_create_chunk(void)
chunk->base_addr = vms[0]->addr - pcpu_group_offsets[0];
pcpu_stats_chunk_alloc();
trace_percpu_create_chunk(chunk->base_addr);
return chunk;
}
@ -352,6 +353,7 @@ static struct pcpu_chunk *pcpu_create_chunk(void)
static void pcpu_destroy_chunk(struct pcpu_chunk *chunk)
{
pcpu_stats_chunk_dealloc();
trace_percpu_destroy_chunk(chunk->base_addr);
if (chunk && chunk->data)
pcpu_free_vm_areas(chunk->data, pcpu_nr_groups);

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@ -76,6 +76,9 @@
#include <asm/tlbflush.h>
#include <asm/io.h>
#define CREATE_TRACE_POINTS
#include <trace/events/percpu.h>
#include "percpu-internal.h"
#define PCPU_SLOT_BASE_SHIFT 5 /* 1-31 shares the same slot */
@ -1015,11 +1018,17 @@ area_found:
ptr = __addr_to_pcpu_ptr(chunk->base_addr + off);
kmemleak_alloc_percpu(ptr, size, gfp);
trace_percpu_alloc_percpu(reserved, is_atomic, size, align,
chunk->base_addr, off, ptr);
return ptr;
fail_unlock:
spin_unlock_irqrestore(&pcpu_lock, flags);
fail:
trace_percpu_alloc_percpu_fail(reserved, is_atomic, size, align);
if (!is_atomic && warn_limit) {
pr_warn("allocation failed, size=%zu align=%zu atomic=%d, %s\n",
size, align, is_atomic, err);
@ -1269,6 +1278,8 @@ void free_percpu(void __percpu *ptr)
}
}
trace_percpu_free_percpu(chunk->base_addr, off, ptr);
spin_unlock_irqrestore(&pcpu_lock, flags);
}
EXPORT_SYMBOL_GPL(free_percpu);
@ -1719,6 +1730,7 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
pcpu_chunk_relocate(pcpu_first_chunk, -1);
pcpu_stats_chunk_alloc();
trace_percpu_create_chunk(base_addr);
/* we're done */
pcpu_base_addr = base_addr;