The flag PERF_X86_EVENT_COMMITTED is used to find uncommitted events for which to call put_event_constraint() when scheduling fails. These are the newly added events to the list, and must form, per definition, the tail of cpuc->event_list[]. By computing the list index of the last successfull schedule, then iteration can start there and the flag is redundant. There are only 3 callers of x86_schedule_events(), notably: - x86_pmu_add() - x86_pmu_commit_txn() - validate_group() For x86_pmu_add(), cpuc->n_events isn't updated until after schedule_events() succeeds, therefore cpuc->n_events points to the desired index. For x86_pmu_commit_txn(), cpuc->n_events is updated, but we can trivially compute the desired value with cpuc->n_txn -- the number of events added in this transaction. For validate_group(), we can make the rule for x86_pmu_add() work by simply setting cpuc->n_events to 0 before calling schedule_events(). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Stephane Eranian <eranian@google.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Ingo Molnar <mingo@kernel.org>
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.
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