diff options
Diffstat (limited to 'include/linux/pipe_fs_i.h')
| -rw-r--r-- | include/linux/pipe_fs_i.h | 26 |
1 files changed, 22 insertions, 4 deletions
diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h index 7f6a92ac9704..6402930282e5 100644 --- a/include/linux/pipe_fs_i.h +++ b/include/linux/pipe_fs_i.h @@ -14,6 +14,9 @@ #define PIPE_BUF_FLAG_LOSS 0x40 /* Message loss happened after this buffer */ #endif +#define PIPE_PREALLOC_MAX 8 /* max pages in prealloc pool */ +#define PIPE_PREALLOC_KEEP 2 /* keep at least this many after trim */ + /** * struct pipe_buffer - a linux kernel pipe buffer * @page: the page containing the data for the pipe buffer @@ -59,6 +62,21 @@ union pipe_index { }; /** + * struct anon_pipe_prealloc - per-pipe page preallocation pool + * @pages: array of cached pages (pool) + * @count: number of pages currently in the pool + * + * Each pipe keeps a small bounded pool of preallocated pages to reduce + * allocation overhead during writes. The pool is bounded at PIPE_PREALLOC_MAX + * and trimmed down to PIPE_PREALLOC_KEEP after a write completes. + */ +struct anon_pipe_prealloc { + struct page *pages[PIPE_PREALLOC_MAX]; + + unsigned int __data_racy count; +}; + +/** * struct pipe_inode_info - a linux kernel pipe * @mutex: mutex protecting the whole thing * @rd_wait: reader wait point in case of empty pipe @@ -68,13 +86,13 @@ union pipe_index { * @max_usage: The maximum number of slots that may be used in the ring * @ring_size: total number of buffers (should be a power of 2) * @nr_accounted: The amount this pipe accounts for in user->pipe_bufs - * @tmp_page: cached released page + * @prealloc: per-pipe page preallocation pool * @readers: number of current readers of this pipe * @writers: number of current writers of this pipe * @files: number of struct file referring this pipe (protected by ->i_lock) * @r_counter: reader counter * @w_counter: writer counter - * @poll_usage: is this pipe used for epoll, which has crazy wakeups? + * @pseudo_edgetrigger: has an EPOLLET consumer, enable per-write wakeups * @fasync_readers: reader side fasync * @fasync_writers: writer side fasync * @bufs: the circular array of pipe buffers @@ -95,11 +113,11 @@ struct pipe_inode_info { unsigned int files; unsigned int r_counter; unsigned int w_counter; - bool poll_usage; + bool pseudo_edgetrigger; #ifdef CONFIG_WATCH_QUEUE bool note_loss; #endif - struct page *tmp_page[2]; + struct anon_pipe_prealloc prealloc; struct fasync_struct *fasync_readers; struct fasync_struct *fasync_writers; struct pipe_buffer *bufs; |