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From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Arnd Bergmann <arnd@arndb.de>,
	Lukas Bulwahn <lukas.bulwahn@gmail.com>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Qiujun Huang <hqjagain@gmail.com>
Subject: [for-linus][PATCH 7/9] ring-buffer: Add rb_check_bpage in __rb_allocate_pages
Date: Wed, 16 Dec 2020 20:04:15 -0500	[thread overview]
Message-ID: <20201217010503.108121702@goodmis.org> (raw)
In-Reply-To: <20201217010408.742794078@goodmis.org>

From: Qiujun Huang <hqjagain@gmail.com>

It may be better to check each page is aligned by 4 bytes. The 2
least significant bits of the address will be used as flags.

Link: https://lkml.kernel.org/r/20201015113842.2921-1-hqjagain@gmail.com

Signed-off-by: Qiujun Huang <hqjagain@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/ring_buffer.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index e97ecf72c727..e03bc4e5d482 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -1423,7 +1423,8 @@ static int rb_check_pages(struct ring_buffer_per_cpu *cpu_buffer)
 	return 0;
 }
 
-static int __rb_allocate_pages(long nr_pages, struct list_head *pages, int cpu)
+static int __rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer,
+		long nr_pages, struct list_head *pages)
 {
 	struct buffer_page *bpage, *tmp;
 	bool user_thread = current->mm != NULL;
@@ -1463,13 +1464,15 @@ static int __rb_allocate_pages(long nr_pages, struct list_head *pages, int cpu)
 		struct page *page;
 
 		bpage = kzalloc_node(ALIGN(sizeof(*bpage), cache_line_size()),
-				    mflags, cpu_to_node(cpu));
+				    mflags, cpu_to_node(cpu_buffer->cpu));
 		if (!bpage)
 			goto free_pages;
 
+		rb_check_bpage(cpu_buffer, bpage);
+
 		list_add(&bpage->list, pages);
 
-		page = alloc_pages_node(cpu_to_node(cpu), mflags, 0);
+		page = alloc_pages_node(cpu_to_node(cpu_buffer->cpu), mflags, 0);
 		if (!page)
 			goto free_pages;
 		bpage->page = page_address(page);
@@ -1501,7 +1504,7 @@ static int rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer,
 
 	WARN_ON(!nr_pages);
 
-	if (__rb_allocate_pages(nr_pages, &pages, cpu_buffer->cpu))
+	if (__rb_allocate_pages(cpu_buffer, nr_pages, &pages))
 		return -ENOMEM;
 
 	/*
@@ -2008,8 +2011,8 @@ int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size,
 			 * allocated without receiving ENOMEM
 			 */
 			INIT_LIST_HEAD(&cpu_buffer->new_pages);
-			if (__rb_allocate_pages(cpu_buffer->nr_pages_to_update,
-						&cpu_buffer->new_pages, cpu)) {
+			if (__rb_allocate_pages(cpu_buffer, cpu_buffer->nr_pages_to_update,
+						&cpu_buffer->new_pages)) {
 				/* not enough memory for new pages */
 				err = -ENOMEM;
 				goto out_err;
@@ -2074,8 +2077,8 @@ 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,
-					    &cpu_buffer->new_pages, cpu_id)) {
+			__rb_allocate_pages(cpu_buffer, cpu_buffer->nr_pages_to_update,
+					    &cpu_buffer->new_pages)) {
 			err = -ENOMEM;
 			goto out_err;
 		}
-- 
2.29.2



  parent reply	other threads:[~2020-12-17  1:13 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-17  1:04 [for-linus][PATCH 0/9] tracing: Last minute fixes before pushing to Linus Steven Rostedt
2020-12-17  1:04 ` [for-linus][PATCH 1/9] ring-buffer: Remove obsolete rb_event_is_commit() Steven Rostedt
2020-12-17  1:04 ` [for-linus][PATCH 2/9] ring-buffer: Fix a typo in function description Steven Rostedt
2020-12-17  1:04 ` [for-linus][PATCH 3/9] seq_buf: Avoid type mismatch for seq_buf_init Steven Rostedt
2020-12-17  1:04 ` [for-linus][PATCH 4/9] tracing: Disable ftrace selftests when any tracer is running Steven Rostedt
2020-12-17  1:04 ` [for-linus][PATCH 5/9] tracing: Drop unneeded assignment in ring_buffer_resize() Steven Rostedt
2020-12-17  1:04 ` [for-linus][PATCH 6/9] ring-buffer: Fix two typos in comments Steven Rostedt
2020-12-17  1:04 ` Steven Rostedt [this message]
2020-12-17  1:04 ` [for-linus][PATCH 8/9] Revert: "ring-buffer: Remove HAVE_64BIT_ALIGNED_ACCESS" Steven Rostedt
2020-12-17  1:04 ` [for-linus][PATCH 9/9] tracing: Offload eval map updates to a work queue Steven Rostedt

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