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author | Nate Diller <nate.diller@gmail.com> | 2006-01-24 09:07:58 (GMT) |
---|---|---|
committer | Jens Axboe <axboe@suse.de> | 2006-01-24 09:07:58 (GMT) |
commit | 5f00397644e01adfbebafb5d0ebc01eba522709d (patch) | |
tree | 30fa87541eb60d74a0c6476a624d827c1da4dbce | |
parent | 53e86061b5bd4aece9bbb6b00b30720200596ecb (diff) | |
download | linux-fsl-qoriq-5f00397644e01adfbebafb5d0ebc01eba522709d.tar.xz |
[BLOCK] elevator: default choice selection
My previous default iosched patch did a poor job dealing with the
'elevator=' boot-time option. The old behavior falls back to the
compiled-in default if the requested one is not registered at boot
time. This patch dynamically evaluates which default
to use, and emits a suitable error message when the requested scheduler
is not available. It also does the 'as' -> 'anticipatory' conversion
before elevator registration, which along with a modified registration
function, allows it to correctly indicate which default scheduler is
in use.
Tested for a range of boot options on 2.6.16-rc1-mm2.
Signed-off-by: Nate Diller <nate.diller@gmail.com>
Signed-off-by: Jens Axboe <axboe@suse.de>
-rw-r--r-- | block/elevator.c | 45 |
1 files changed, 14 insertions, 31 deletions
diff --git a/block/elevator.c b/block/elevator.c index c9f424d..dbbea73 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -139,35 +139,16 @@ static int elevator_attach(request_queue_t *q, struct elevator_type *e, static char chosen_elevator[16]; -static void elevator_setup_default(void) +static int __init elevator_setup(char *str) { - struct elevator_type *e; - - /* - * If default has not been set, use the compiled-in selection. - */ - if (!chosen_elevator[0]) - strcpy(chosen_elevator, CONFIG_DEFAULT_IOSCHED); - /* * Be backwards-compatible with previous kernels, so users * won't get the wrong elevator. */ - if (!strcmp(chosen_elevator, "as")) + if (!strcmp(str, "as")) strcpy(chosen_elevator, "anticipatory"); - - /* - * If the given scheduler is not available, fall back to the default - */ - if ((e = elevator_find(chosen_elevator))) - elevator_put(e); else - strcpy(chosen_elevator, CONFIG_DEFAULT_IOSCHED); -} - -static int __init elevator_setup(char *str) -{ - strncpy(chosen_elevator, str, sizeof(chosen_elevator) - 1); + strncpy(chosen_elevator, str, sizeof(chosen_elevator) - 1); return 0; } @@ -184,15 +165,15 @@ int elevator_init(request_queue_t *q, char *name) q->end_sector = 0; q->boundary_rq = NULL; - elevator_setup_default(); - - if (!name) - name = chosen_elevator; - - e = elevator_get(name); - if (!e) + if (name && !(e = elevator_get(name))) return -EINVAL; + if (!e && !(e = elevator_get(chosen_elevator))) { + e = elevator_get(CONFIG_DEFAULT_IOSCHED); + if (*chosen_elevator) + printk("I/O scheduler %s not found\n", chosen_elevator); + } + eq = kmalloc(sizeof(struct elevator_queue), GFP_KERNEL); if (!eq) { elevator_put(e); @@ -669,8 +650,10 @@ int elv_register(struct elevator_type *e) spin_unlock_irq(&elv_list_lock); printk(KERN_INFO "io scheduler %s registered", e->elevator_name); - if (!strcmp(e->elevator_name, chosen_elevator)) - printk(" (default)"); + if (!strcmp(e->elevator_name, chosen_elevator) || + (!*chosen_elevator && + !strcmp(e->elevator_name, CONFIG_DEFAULT_IOSCHED))) + printk(" (default)"); printk("\n"); return 0; } |