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linux-next/fs/pstore/internal.h
Joel Fernandes fbccdeb8d7 pstore: Add ftrace timestamp counter
In preparation for merging the per CPU buffers into one buffer when
we retrieve the pstore ftrace data, we store the timestamp as a
counter in the ftrace pstore record.  We store the CPU number as well
if !PSTORE_CPU_IN_IP, in this case we shift the counter and may lose
ordering there but we preserve the same record size. The timestamp counter
is also racy, and not doing any locking or synchronization here results
in the benefit of lower overhead. Since we don't care much here for exact
ordering of function traces across CPUs, we don't synchronize and may lose
some counter updates but I'm ok with that.

Using trace_clock() results in much lower performance so avoid using it
since we don't want accuracy in timestamp and need a rough ordering to
perform merge.

Signed-off-by: Joel Fernandes <joelaf@google.com>
[kees: updated commit message, added comments]
Signed-off-by: Kees Cook <keescook@chromium.org>
2016-11-15 16:34:27 -08:00

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945 B
C

#ifndef __PSTORE_INTERNAL_H__
#define __PSTORE_INTERNAL_H__
#include <linux/types.h>
#include <linux/time.h>
#include <linux/pstore.h>
#ifdef CONFIG_PSTORE_FTRACE
extern void pstore_register_ftrace(void);
extern void pstore_unregister_ftrace(void);
#else
static inline void pstore_register_ftrace(void) {}
static inline void pstore_unregister_ftrace(void) {}
#endif
#ifdef CONFIG_PSTORE_PMSG
extern void pstore_register_pmsg(void);
extern void pstore_unregister_pmsg(void);
#else
static inline void pstore_register_pmsg(void) {}
static inline void pstore_unregister_pmsg(void) {}
#endif
extern struct pstore_info *psinfo;
extern void pstore_set_kmsg_bytes(int);
extern void pstore_get_records(int);
extern int pstore_mkfile(enum pstore_type_id, char *psname, u64 id,
int count, char *data, bool compressed,
size_t size, struct timespec time,
struct pstore_info *psi);
extern bool pstore_is_mounted(void);
#endif