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Date: Wed, 2 Sep 2020 13:00:21 -0700
From: Nachammai Karuppiah <nachukannan@...il.com>
To: Steven Rostedt <rostedt@...dmis.org>,
Ingo Molnar <mingo@...hat.com>,
Rob Herring <robh+dt@...nel.org>,
Frank Rowand <frowand.list@...il.com>,
Kees Cook <keescook@...omium.org>,
Anton Vorontsov <anton@...msg.org>,
Colin Cross <ccross@...roid.com>,
Tony Luck <tony.luck@...el.com>
Cc: joel@...lfernandes.org, linux-kernel@...r.kernel.org,
Nachammai Karuppiah <nachukannan@...il.com>
Subject: [RFC PATCH 6/7] tracing: Use ramtrace alloc and free methods while using persistent RAM
If persistent RAM is being used to record trace entries, allocate and
free pages using ramtrace_alloc_page and ramtrace_free_page.
Signed-off-by: Nachammai Karuppiah <nachukannan@...il.com>
---
kernel/trace/ring_buffer.c | 122 +++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 119 insertions(+), 3 deletions(-)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 34e50c1..c99719e 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -353,6 +353,18 @@ static void free_buffer_page(struct buffer_page *bpage)
kfree(bpage);
}
+#ifdef CONFIG_TRACE_EVENTS_TO_PSTORE
+static void
+free_buffer_page_cpu(struct buffer_page *bpage, int cpu, bool use_pstore)
+{
+ if (use_pstore) {
+ ramtrace_free_page(bpage->page, cpu);
+ kfree(bpage);
+ } else
+ free_buffer_page(bpage);
+}
+#endif
+
/*
* We need to fit the time_stamp delta into 27 bits.
*/
@@ -1200,7 +1212,12 @@ static int rb_check_pages(struct ring_buffer_per_cpu *cpu_buffer)
return 0;
}
+#ifdef CONFIG_TRACE_EVENTS_TO_PSTORE
+static int __rb_allocate_pages(long nr_pages, struct list_head *pages, int cpu,
+ bool use_pstore)
+#else
static int __rb_allocate_pages(long nr_pages, struct list_head *pages, int cpu)
+#endif
{
struct buffer_page *bpage, *tmp;
bool user_thread = current->mm != NULL;
@@ -1214,6 +1231,11 @@ static int __rb_allocate_pages(long nr_pages, struct list_head *pages, int cpu)
* to prevent doing any allocation when it is obvious that it is
* not going to succeed.
*/
+#ifdef CONFIG_TRACE_EVENTS_TO_PSTORE
+ if (use_pstore)
+ i = ramtrace_available_mem();
+ else
+#endif
i = si_mem_available();
if (i < nr_pages)
return -ENOMEM;
@@ -1246,10 +1268,22 @@ static int __rb_allocate_pages(long nr_pages, struct list_head *pages, int cpu)
list_add(&bpage->list, pages);
+#ifdef CONFIG_TRACE_EVENTS_TO_PSTORE
+ if (use_pstore) {
+ void *address = ramtrace_alloc_page(cpu);
+
+ if (!address)
+ goto free_pages;
+ bpage->page = address;
+ } else {
+#endif
page = alloc_pages_node(cpu_to_node(cpu), mflags, 0);
if (!page)
goto free_pages;
bpage->page = page_address(page);
+#ifdef CONFIG_TRACE_EVENTS_TO_PSTORE
+ }
+#endif
rb_init_page(bpage->page);
if (user_thread && fatal_signal_pending(current))
@@ -1263,7 +1297,11 @@ static int __rb_allocate_pages(long nr_pages, struct list_head *pages, int cpu)
free_pages:
list_for_each_entry_safe(bpage, tmp, pages, list) {
list_del_init(&bpage->list);
+#ifdef CONFIG_TRACE_EVENTS_TO_PSTORE
+ free_buffer_page_cpu(bpage, cpu, use_pstore);
+#else
free_buffer_page(bpage);
+#endif
}
if (user_thread)
clear_current_oom_origin();
@@ -1278,7 +1316,12 @@ static int rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer,
WARN_ON(!nr_pages);
+#ifdef CONFIG_TRACE_EVENTS_TO_PSTORE
+ if (__rb_allocate_pages(nr_pages, &pages, cpu_buffer->cpu,
+ cpu_buffer->use_pstore))
+#else
if (__rb_allocate_pages(nr_pages, &pages, cpu_buffer->cpu))
+#endif
return -ENOMEM;
/*
@@ -1414,10 +1457,23 @@ rb_allocate_cpu_buffer(struct trace_buffer *buffer, long nr_pages, int cpu)
rb_check_bpage(cpu_buffer, bpage);
cpu_buffer->reader_page = bpage;
+
+#ifdef CONFIG_TRACE_EVENTS_TO_PSTORE
+ if (cpu_buffer->use_pstore) {
+ void *address = ramtrace_alloc_page(cpu);
+
+ if (!address)
+ goto fail_free_reader;
+ bpage->page = address;
+ } else {
+#endif
page = alloc_pages_node(cpu_to_node(cpu), GFP_KERNEL, 0);
if (!page)
goto fail_free_reader;
bpage->page = page_address(page);
+#ifdef CONFIG_TRACE_EVENTS_TO_PSTORE
+ }
+#endif
rb_init_page(bpage->page);
INIT_LIST_HEAD(&cpu_buffer->reader_page->list);
@@ -1436,7 +1492,12 @@ rb_allocate_cpu_buffer(struct trace_buffer *buffer, long nr_pages, int cpu)
return cpu_buffer;
fail_free_reader:
+#ifdef CONFIG_TRACE_EVENTS_TO_PSTORE
+ free_buffer_page_cpu(cpu_buffer->reader_page, cpu,
+ cpu_buffer->use_pstore);
+#else
free_buffer_page(cpu_buffer->reader_page);
+#endif
fail_free_buffer:
kfree(cpu_buffer);
@@ -1447,18 +1508,32 @@ static void rb_free_cpu_buffer(struct ring_buffer_per_cpu *cpu_buffer)
{
struct list_head *head = cpu_buffer->pages;
struct buffer_page *bpage, *tmp;
-
+#ifdef CONFIG_TRACE_EVENTS_TO_PSTORE
+ free_buffer_page_cpu(cpu_buffer->reader_page, cpu_buffer->cpu,
+ cpu_buffer->use_pstore);
+#else
free_buffer_page(cpu_buffer->reader_page);
+#endif
rb_head_page_deactivate(cpu_buffer);
if (head) {
list_for_each_entry_safe(bpage, tmp, head, list) {
list_del_init(&bpage->list);
+#ifdef CONFIG_TRACE_EVENTS_TO_PSTORE
+ free_buffer_page_cpu(bpage, cpu_buffer->cpu,
+ cpu_buffer->use_pstore);
+#else
free_buffer_page(bpage);
+#endif
}
bpage = list_entry(head, struct buffer_page, list);
+#ifdef CONFIG_TRACE_EVENTS_TO_PSTORE
+ free_buffer_page_cpu(bpage, cpu_buffer->cpu,
+ cpu_buffer->use_pstore);
+#else
free_buffer_page(bpage);
+#endif
}
kfree(cpu_buffer);
@@ -1832,7 +1907,12 @@ rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned long nr_pages)
* We have already removed references to this list item, just
* free up the buffer_page and its page
*/
+#ifdef CONFIG_TRACE_EVENTS_TO_PSTORE
+ free_buffer_page_cpu(to_remove_page, cpu_buffer->cpu,
+ cpu_buffer->use_pstore);
+#else
free_buffer_page(to_remove_page);
+#endif
nr_removed--;
} while (to_remove_page != last_page);
@@ -1913,7 +1993,12 @@ rb_insert_pages(struct ring_buffer_per_cpu *cpu_buffer)
list_for_each_entry_safe(bpage, tmp, &cpu_buffer->new_pages,
list) {
list_del_init(&bpage->list);
+#ifdef CONFIG_TRACE_EVENTS_TO_PSTORE
+ free_buffer_page_cpu(bpage, cpu_buffer->cpu,
+ cpu_buffer->use_pstore);
+#else
free_buffer_page(bpage);
+#endif
}
}
return success;
@@ -2252,8 +2337,14 @@ int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size,
* allocated without receiving ENOMEM
*/
INIT_LIST_HEAD(&cpu_buffer->new_pages);
+#ifdef CONFIG_TRACE_EVENTS_TO_PSTORE
+ if (__rb_allocate_pages(cpu_buffer->nr_pages_to_update,
+ &cpu_buffer->new_pages, cpu,
+ cpu_buffer->use_pstore)) {
+#else
if (__rb_allocate_pages(cpu_buffer->nr_pages_to_update,
&cpu_buffer->new_pages, cpu)) {
+#endif
/* not enough memory for new pages */
err = -ENOMEM;
goto out_err;
@@ -2319,7 +2410,12 @@ int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size,
INIT_LIST_HEAD(&cpu_buffer->new_pages);
if (cpu_buffer->nr_pages_to_update > 0 &&
__rb_allocate_pages(cpu_buffer->nr_pages_to_update,
+#ifdef CONFIG_TRACE_EVENTS_TO_PSTORE
+ &cpu_buffer->new_pages, cpu_id,
+ cpu_buffer->use_pstore)) {
+#else
&cpu_buffer->new_pages, cpu_id)) {
+#endif
err = -ENOMEM;
goto out_err;
}
@@ -2379,7 +2475,12 @@ int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size,
list_for_each_entry_safe(bpage, tmp, &cpu_buffer->new_pages,
list) {
list_del_init(&bpage->list);
+#ifdef CONFIG_TRACE_EVENTS_TO_PSTORE
+ free_buffer_page_cpu(bpage, cpu,
+ cpu_buffer->use_pstore);
+#else
free_buffer_page(bpage);
+#endif
}
}
out_err_unlock:
@@ -5184,13 +5285,22 @@ void *ring_buffer_alloc_read_page(struct trace_buffer *buffer, int cpu)
if (bpage)
goto out;
+#ifdef CONFIG_TRACE_EVENTS_TO_PSTORE
+ if (cpu_buffer->use_pstore) {
+ bpage = (struct buffer_data_page *)ramtrace_alloc_page(cpu);
+ if (!bpage)
+ return ERR_PTR(-ENOMEM);
+ } else {
+#endif
page = alloc_pages_node(cpu_to_node(cpu),
GFP_KERNEL | __GFP_NORETRY, 0);
if (!page)
return ERR_PTR(-ENOMEM);
bpage = page_address(page);
-
+#ifdef CONFIG_TRACE_EVENTS_TO_PSTORE
+ }
+#endif
out:
rb_init_page(bpage);
down_read(&trace_read_sem);
@@ -5229,7 +5339,13 @@ void ring_buffer_free_read_page(struct trace_buffer *buffer, int cpu, void *data
arch_spin_unlock(&cpu_buffer->lock);
local_irq_restore(flags);
- out:
+out:
+#ifdef CONFIG_TRACE_EVENTS_TO_PSTORE
+ if (cpu_buffer->use_pstore) {
+ ramtrace_free_page(bpage, cpu);
+ return;
+ }
+#endif
free_page((unsigned long)bpage);
up_read(&trace_read_sem);
}
--
2.7.4
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