Systemd/src/core/swap.h
Lennart Poettering a57f7e2c82 core: rework how we match mount units against each other
Previously to automatically create dependencies between mount units we
matched every mount unit agains all others resulting in O(n^2)
complexity. On setups with large amounts of mount units this might make
things slow.

This change replaces the matching code to use a hashtable that is keyed
by a path prefix, and points to a set of units that require that path to
be around. When a new mount unit is installed it is hence sufficient to
simply look up this set of units via its own file system paths to know
which units to order after itself.

This patch also changes all unit types to only create automatic mount
dependencies via the RequiresMountsFor= logic, and this is exposed to
the outside to make things more transparent.

With this change we still have some O(n) complexities in place when
handling mounts, but that's currently unavoidable due to kernel APIs,
and still substantially better than O(n^2) as before.

https://bugs.freedesktop.org/show_bug.cgi?id=69740
2013-09-26 20:20:30 +02:00

121 lines
3.2 KiB
C

/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
#pragma once
/***
This file is part of systemd.
Copyright 2010 Lennart Poettering
Copyright 2010 Maarten Lankhorst
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
typedef struct Swap Swap;
#include "unit.h"
typedef enum SwapState {
SWAP_DEAD,
SWAP_ACTIVATING,
SWAP_ACTIVE,
SWAP_DEACTIVATING,
SWAP_ACTIVATING_SIGTERM,
SWAP_ACTIVATING_SIGKILL,
SWAP_DEACTIVATING_SIGTERM,
SWAP_DEACTIVATING_SIGKILL,
SWAP_FAILED,
_SWAP_STATE_MAX,
_SWAP_STATE_INVALID = -1
} SwapState;
typedef enum SwapExecCommand {
SWAP_EXEC_ACTIVATE,
SWAP_EXEC_DEACTIVATE,
_SWAP_EXEC_COMMAND_MAX,
_SWAP_EXEC_COMMAND_INVALID = -1
} SwapExecCommand;
typedef struct SwapParameters {
char *what;
int priority;
bool noauto:1;
bool nofail:1;
} SwapParameters;
typedef enum SwapResult {
SWAP_SUCCESS,
SWAP_FAILURE_RESOURCES,
SWAP_FAILURE_TIMEOUT,
SWAP_FAILURE_EXIT_CODE,
SWAP_FAILURE_SIGNAL,
SWAP_FAILURE_CORE_DUMP,
_SWAP_RESULT_MAX,
_SWAP_RESULT_INVALID = -1
} SwapResult;
struct Swap {
Unit meta;
char *what;
SwapParameters parameters_proc_swaps;
SwapParameters parameters_fragment;
bool from_proc_swaps:1;
bool from_fragment:1;
/* Used while looking for swaps that vanished or got added
* from/to /proc/swaps */
bool is_active:1;
bool just_activated:1;
SwapResult result;
usec_t timeout_usec;
ExecCommand exec_command[_SWAP_EXEC_COMMAND_MAX];
ExecContext exec_context;
KillContext kill_context;
CGroupContext cgroup_context;
SwapState state, deserialized_state;
ExecCommand* control_command;
SwapExecCommand control_command_id;
pid_t control_pid;
Watch timer_watch;
/* In order to be able to distinguish dependencies on
different device nodes we might end up creating multiple
devices for the same swap. We chain them up here. */
LIST_FIELDS(struct Swap, same_proc_swaps);
};
extern const UnitVTable swap_vtable;
int swap_dispatch_reload(Manager *m);
int swap_fd_event(Manager *m, int events);
const char* swap_state_to_string(SwapState i) _const_;
SwapState swap_state_from_string(const char *s) _pure_;
const char* swap_exec_command_to_string(SwapExecCommand i) _const_;
SwapExecCommand swap_exec_command_from_string(const char *s) _pure_;
const char* swap_result_to_string(SwapResult i) _const_;
SwapResult swap_result_from_string(const char *s) _pure_;