Messages in this thread Patch in this message |  | | Date | Mon, 18 Feb 2008 19:16:30 +0100 | | From | Jens Axboe <> | | Subject | Re: [PATCH 1/1] NBD: make nbd default to deadline I/O scheduler |
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On Tue, Feb 12 2008, Andrew Morton wrote: > On Sat, 09 Feb 2008 08:30:40 -0500 > Paul Clements <paul.clements@steeleye.com> wrote: > > > + old_e = disk->queue->elevator; > > + if (elevator_init(disk->queue, "deadline") == 0 || > > + elevator_init(disk->queue, "noop") == 0) { > > + elevator_exit(old_e); > > + } > > } > > afacit elevator_init() will not trigger a request_module(). And you really > do want to trigger the request_module() here. Perhaps the block layer > should provide a means of doing so?
Good point, I think elevator_get() should do that automatically. Does this look sane?
diff --git a/block/elevator.c b/block/elevator.c index bafbae0..88318c3 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -134,6 +134,21 @@ static struct elevator_type *elevator_get(const char *name) spin_lock(&elv_list_lock); e = elevator_find(name); + if (!e) { + char elv[ELV_NAME_MAX + strlen("-iosched")]; + + spin_unlock(&elv_list_lock); + + if (!strcmp(name, "anticipatory")) + sprintf(elv, "as-iosched"); + else + sprintf(elv, "%s-iosched", name); + + request_module(elv); + spin_lock(&elv_list_lock); + e = elevator_find(name); + } + if (e && !try_module_get(e->elevator_owner)) e = NULL; -- Jens Axboe
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