tracing: remove on the fly allocator from function profiler (318e0a73) · Commits · 戴 / test

kernel/trace/ftrace.c

+43 −33

Original line number	Diff line number	Diff line
		@@ -401,6 +401,8 @@ static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
		int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
		{
		struct ftrace_profile_page *pg;
		int functions;
		int pages;
		int i;

		/* If we already allocated, do nothing */
		@@ -411,22 +413,46 @@ int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
		if (!stat->pages)
		return -ENOMEM;

		#ifdef CONFIG_DYNAMIC_FTRACE
		functions = ftrace_update_tot_cnt;
		#else
		/*
		* We do not know the number of functions that exist because
		* dynamic tracing is what counts them. With past experience
		* we have around 20K functions. That should be more than enough.
		* It is highly unlikely we will execute every function in
		* the kernel.
		*/
		functions = 20000;
		#endif

		pg = stat->start = stat->pages;

		/* allocate 10 more pages to start */
		for (i = 0; i < 10; i++) {
		pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);

		for (i = 0; i < pages; i++) {
		pg->next = (void *)get_zeroed_page(GFP_KERNEL);
		/*
		* We only care about allocating profile_pages, if
		* we failed to allocate here, hopefully we will allocate
		* later.
		*/
		if (!pg->next)
		break;
		goto out_free;
		pg = pg->next;
		}

		return 0;

		out_free:
		pg = stat->start;
		while (pg) {
		unsigned long tmp = (unsigned long)pg;

		pg = pg->next;
		free_page(tmp);
		}

		free_page((unsigned long)stat->pages);
		stat->pages = NULL;
		stat->start = NULL;

		return -ENOMEM;
		}

		static int ftrace_profile_init_cpu(int cpu)
		@@ -460,7 +486,7 @@ static int ftrace_profile_init_cpu(int cpu)
		ftrace_profile_bits++;
		}

		/* Preallocate a few pages */
		/* Preallocate the function profiling pages */
		if (ftrace_profile_pages_init(stat) < 0) {
		kfree(stat->hash);
		stat->hash = NULL;
		@@ -516,24 +542,21 @@ static void ftrace_add_profile(struct ftrace_profile_stat *stat,
		hlist_add_head_rcu(&rec->node, &stat->hash[key]);
		}

		/* Interrupts must be disabled calling this */
		/*
		* The memory is already allocated, this simply finds a new record to use.
		*/
		static struct ftrace_profile *
		ftrace_profile_alloc(struct ftrace_profile_stat *stat,
		unsigned long ip, bool alloc_safe)
		ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
		{
		struct ftrace_profile *rec = NULL;

		/* prevent recursion */
		/* prevent recursion (from NMIs) */
		if (atomic_inc_return(&stat->disabled) != 1)
		goto out;

		/* Try to always keep another page available */
		if (!stat->pages->next && alloc_safe)
		stat->pages->next = (void *)get_zeroed_page(GFP_ATOMIC);

		/*
		* Try to find the function again since another
		* task on another CPU could have added it
		* Try to find the function again since an NMI
		* could have added it
		*/
		rec = ftrace_find_profiled_func(stat, ip);
		if (rec)
		@@ -555,29 +578,16 @@ ftrace_profile_alloc(struct ftrace_profile_stat *stat,
		return rec;
		}

		/*
		* If we are not in an interrupt, or softirq and
		* and interrupts are disabled and preemption is not enabled
		* (not in a spinlock) then it should be safe to allocate memory.
		*/
		static bool ftrace_safe_to_allocate(void)
		{
		return !in_interrupt() && irqs_disabled() && !preempt_count();
		}

		static void
		function_profile_call(unsigned long ip, unsigned long parent_ip)
		{
		struct ftrace_profile_stat *stat;
		struct ftrace_profile *rec;
		unsigned long flags;
		bool alloc_safe;

		if (!ftrace_profile_enabled)
		return;

		alloc_safe = ftrace_safe_to_allocate();

		local_irq_save(flags);

		stat = &__get_cpu_var(ftrace_profile_stats);
		@@ -586,7 +596,7 @@ function_profile_call(unsigned long ip, unsigned long parent_ip)

		rec = ftrace_find_profiled_func(stat, ip);
		if (!rec) {
		rec = ftrace_profile_alloc(stat, ip, alloc_safe);
		rec = ftrace_profile_alloc(stat, ip);
		if (!rec)
		goto out;
		}

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