Pipes can consume a significant amount of system memory, hence they
should be accounted to kmemcg.
This patch marks pipe_inode_info and anonymous pipe buffer page
allocations as __GFP_ACCOUNT so that they would be charged to kmemcg.
Note, since a pipe buffer page can be "stolen" and get reused for other
purposes, including mapping to userspace, we clear PageKmemcg thus
resetting page->_mapcount and uncharge it in anon_pipe_buf_steal, which
is introduced by this patch.
Signed-off-by: Vladimir Davydov <vdavy...@virtuozzo.com>
Cc: Alexander Viro <v...@zeniv.linux.org.uk>
---
fs/pipe.c | 32 ++++++++++++++++++++++++++------
1 file changed, 26 insertions(+), 6 deletions(-)
diff --git a/fs/pipe.c b/fs/pipe.c
index 0d3f5165cb0b..4b32928f5426 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -21,6 +21,7 @@
#include <linux/audit.h>
#include <linux/syscalls.h>
#include <linux/fcntl.h>
+#include <linux/memcontrol.h>
#include <asm/uaccess.h>
#include <asm/ioctls.h>
@@ -137,6 +138,22 @@ static void anon_pipe_buf_release(struct pipe_inode_info
*pipe,
put_page(page);
}
+static int anon_pipe_buf_steal(struct pipe_inode_info *pipe,
+ struct pipe_buffer *buf)
+{
+ struct page *page = buf->page;
+
+ if (page_count(page) == 1) {
+ if (memcg_kmem_enabled()) {
+ memcg_kmem_uncharge(page, 0);
+ __ClearPageKmemcg(page);
+ }
+ __SetPageLocked(page);
+ return 0;
+ }
+ return 1;
+}
+
/**
* generic_pipe_buf_steal - attempt to take ownership of a &pipe_buffer
* @pipe: the pipe that the buffer belongs to
@@ -219,7 +236,7 @@ static const struct pipe_buf_operations anon_pipe_buf_ops =
{
.can_merge = 1,
.confirm = generic_pipe_buf_confirm,
.release = anon_pipe_buf_release,
- .steal = generic_pipe_buf_steal,
+ .steal = anon_pipe_buf_steal,
.get = generic_pipe_buf_get,
};
@@ -227,7 +244,7 @@ static const struct pipe_buf_operations packet_pipe_buf_ops
= {
.can_merge = 0,
.confirm = generic_pipe_buf_confirm,
.release = anon_pipe_buf_release,
- .steal = generic_pipe_buf_steal,
+ .steal = anon_pipe_buf_steal,
.get = generic_pipe_buf_get,
};
@@ -405,7 +422,7 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
int copied;
if (!page) {
- page = alloc_page(GFP_HIGHUSER);
+ page = alloc_page(GFP_HIGHUSER | __GFP_ACCOUNT);
if (unlikely(!page)) {
ret = ret ? : -ENOMEM;
break;
@@ -611,7 +628,7 @@ struct pipe_inode_info *alloc_pipe_info(void)
{
struct pipe_inode_info *pipe;
- pipe = kzalloc(sizeof(struct pipe_inode_info), GFP_KERNEL);
+ pipe = kzalloc(sizeof(struct pipe_inode_info), GFP_KERNEL_ACCOUNT);
if (pipe) {
unsigned long pipe_bufs = PIPE_DEF_BUFFERS;
struct user_struct *user = get_current_user();
@@ -619,7 +636,9 @@ struct pipe_inode_info *alloc_pipe_info(void)
if (!too_many_pipe_buffers_hard(user)) {
if (too_many_pipe_buffers_soft(user))
pipe_bufs = 1;
- pipe->bufs = kzalloc(sizeof(struct pipe_buffer) *
pipe_bufs, GFP_KERNEL);
+ pipe->bufs = kcalloc(pipe_bufs,
+ sizeof(struct pipe_buffer),
+ GFP_KERNEL_ACCOUNT);
}
if (pipe->bufs) {
@@ -1010,7 +1029,8 @@ static long pipe_set_size(struct pipe_inode_info *pipe,
unsigned long nr_pages)
if (nr_pages < pipe->nrbufs)
return -EBUSY;
- bufs = kcalloc(nr_pages, sizeof(*bufs), GFP_KERNEL | __GFP_NOWARN);
+ bufs = kcalloc(nr_pages, sizeof(*bufs),
+ GFP_KERNEL_ACCOUNT | __GFP_NOWARN);
if (unlikely(!bufs))
return -ENOMEM;
--
2.1.4
