mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-15 23:25:07 +00:00
39d6d08b2e
User processes may require many events and when they do the cache performance of a byte index status check is less ideal than a bit index. The previous event limit per-page was 4096, the new limit is 32,768. This change adds a bitwise index to the user_reg struct. Programs check that the bit at status_bit has a bit set within the status page(s). Link: https://lkml.kernel.org/r/20220728233309.1896-6-beaub@linux.microsoft.com Link: https://lore.kernel.org/all/2059213643.196683.1648499088753.JavaMail.zimbra@efficios.com/ Suggested-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
54 lines
1.4 KiB
C
54 lines
1.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
|
|
/*
|
|
* Copyright (c) 2021, Microsoft Corporation.
|
|
*
|
|
* Authors:
|
|
* Beau Belgrave <beaub@linux.microsoft.com>
|
|
*/
|
|
#ifndef _UAPI_LINUX_USER_EVENTS_H
|
|
#define _UAPI_LINUX_USER_EVENTS_H
|
|
|
|
#include <linux/types.h>
|
|
#include <linux/ioctl.h>
|
|
|
|
#ifdef __KERNEL__
|
|
#include <linux/uio.h>
|
|
#else
|
|
#include <sys/uio.h>
|
|
#endif
|
|
|
|
#define USER_EVENTS_SYSTEM "user_events"
|
|
#define USER_EVENTS_PREFIX "u:"
|
|
|
|
/* Create dynamic location entry within a 32-bit value */
|
|
#define DYN_LOC(offset, size) ((size) << 16 | (offset))
|
|
|
|
/*
|
|
* Describes an event registration and stores the results of the registration.
|
|
* This structure is passed to the DIAG_IOCSREG ioctl, callers at a minimum
|
|
* must set the size and name_args before invocation.
|
|
*/
|
|
struct user_reg {
|
|
|
|
/* Input: Size of the user_reg structure being used */
|
|
__u32 size;
|
|
|
|
/* Input: Pointer to string with event name, description and flags */
|
|
__u64 name_args;
|
|
|
|
/* Output: Bitwise index of the event within the status page */
|
|
__u32 status_bit;
|
|
|
|
/* Output: Index of the event to use when writing data */
|
|
__u32 write_index;
|
|
} __attribute__((__packed__));
|
|
|
|
#define DIAG_IOC_MAGIC '*'
|
|
|
|
/* Requests to register a user_event */
|
|
#define DIAG_IOCSREG _IOWR(DIAG_IOC_MAGIC, 0, struct user_reg*)
|
|
|
|
/* Requests to delete a user_event */
|
|
#define DIAG_IOCSDEL _IOW(DIAG_IOC_MAGIC, 1, char*)
|
|
|
|
#endif /* _UAPI_LINUX_USER_EVENTS_H */
|