[PATCH] Optimize select/poll by putting small data sets on the stack

[net-next-2.6.git] / include / linux / poll.h

diff --git a/include/linux/poll.h b/include/linux/poll.h
index 8e8f6098508aca2992e6402f12e83087d3846757..51e1b56741fb153013e50f6b1167b9a36345232f 100644 (file)
--- a/include/linux/poll.h
+++ b/include/linux/poll.h
@@ -11,6 +11,15 @@
 #include <linux/mm.h>
 #include <asm/uaccess.h>
 
+/* ~832 bytes of stack space used max in sys_select/sys_poll before allocating
+   additional memory. */
+#define MAX_STACK_ALLOC 832
+#define FRONTEND_STACK_ALLOC   256
+#define SELECT_STACK_ALLOC     FRONTEND_STACK_ALLOC
+#define POLL_STACK_ALLOC       FRONTEND_STACK_ALLOC
+#define WQUEUES_STACK_ALLOC    (MAX_STACK_ALLOC - FRONTEND_STACK_ALLOC)
+#define N_INLINE_POLL_ENTRIES  (WQUEUES_STACK_ALLOC / sizeof(struct poll_table_entry))
+
 struct poll_table_struct;
 
 /* 
@@ -33,6 +42,12 @@ static inline void init_poll_funcptr(poll_table *pt, poll_queue_proc qproc)
        pt->qproc = qproc;
 }
 
+struct poll_table_entry {
+       struct file * filp;
+       wait_queue_t wait;
+       wait_queue_head_t * wait_address;
+};
+
 /*
  * Structures and helpers for sys_poll/sys_poll
  */
@@ -40,6 +55,8 @@ struct poll_wqueues {
        poll_table pt;
        struct poll_table_page * table;
        int error;
+       int inline_index;
+       struct poll_table_entry inline_entries[N_INLINE_POLL_ENTRIES];
 };
 
 extern void poll_initwait(struct poll_wqueues *pwq);