Messages in this thread Patch in this message | | | Date | Fri, 09 Nov 2012 12:09:38 +0100 | From | Daniel Wagner <> | Subject | Re: [PATCH 1/9 v3] cgroup: add cgroup_subsys->post_create() |
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Hi Tejun,
On 08.11.2012 20:07, Tejun Heo wrote:> Subject: cgroup: add cgroup_subsys->post_create() > > Currently, there's no way for a controller to find out whether a new > cgroup finished all ->create() allocatinos successfully and is > considered "live" by cgroup.
I'd like add hierarchy support to net_prio and the first thing to do is to get rid of get_prioidx(). It looks like it would be nice to be able to use use_id and post_create() for this but as I read the code this might not work because the netdev might access resources allocated between create() and post_create(). So my question is would it make sense to move
cgroup_create():
if (ss->use_id) { err = alloc_css_id(ss, parent, cgrp); if (err) goto err_destroy; }
part before create() or add some protection between create() and post_create() callback in net_prio. I have a patch but I see I could drop it completely if post_create() is there.
cheers, daniel
From 84fbbdf0dc5d3460389e39a00a3ee553ee55b563 Mon Sep 17 00:00:00 2001 From: Daniel Wagner <daniel.wagner@bmw-carit.de> Date: Thu, 8 Nov 2012 17:17:21 +0100 Subject: [PATCH] cgroups: net_prio: Use IDR library to assign netprio index
get_prioidx() allocated a new id whenever it was called. put_prioidx() gave an id back. get_pioidx() could can reallocate the id later on. So that is exactly what IDR offers and so let's use it.
Signed-off-by: Daniel Wagner <daniel.wagner@bmw-carit.de> --- net/core/netprio_cgroup.c | 51 +++++++++-------------------------------------- 1 file changed, 9 insertions(+), 42 deletions(-)
diff --git a/net/core/netprio_cgroup.c b/net/core/netprio_cgroup.c index 847c02b..3c1b612 100644 --- a/net/core/netprio_cgroup.c +++ b/net/core/netprio_cgroup.c @@ -27,10 +27,7 @@
#include <linux/fdtable.h>
-#define PRIOIDX_SZ 128 - -static unsigned long prioidx_map[PRIOIDX_SZ]; -static DEFINE_SPINLOCK(prioidx_map_lock); +static DEFINE_IDA(netprio_ida); static atomic_t max_prioidx = ATOMIC_INIT(0);
static inline struct cgroup_netprio_state *cgrp_netprio_state(struct cgroup *cgrp) @@ -39,34 +36,6 @@ static inline struct cgroup_netprio_state *cgrp_netprio_state(struct cgroup *cgr struct cgroup_netprio_state, css); }
-static int get_prioidx(u32 *prio) -{ - unsigned long flags; - u32 prioidx; - - spin_lock_irqsave(&prioidx_map_lock, flags); - prioidx = find_first_zero_bit(prioidx_map, sizeof(unsigned long) * PRIOIDX_SZ); - if (prioidx == sizeof(unsigned long) * PRIOIDX_SZ) { - spin_unlock_irqrestore(&prioidx_map_lock, flags); - return -ENOSPC; - } - set_bit(prioidx, prioidx_map); - if (atomic_read(&max_prioidx) < prioidx) - atomic_set(&max_prioidx, prioidx); - spin_unlock_irqrestore(&prioidx_map_lock, flags); - *prio = prioidx; - return 0; -} - -static void put_prioidx(u32 idx) -{ - unsigned long flags; - - spin_lock_irqsave(&prioidx_map_lock, flags); - clear_bit(idx, prioidx_map); - spin_unlock_irqrestore(&prioidx_map_lock, flags); -} - static int extend_netdev_table(struct net_device *dev, u32 new_len) { size_t new_size = sizeof(struct netprio_map) + @@ -120,9 +89,9 @@ static struct cgroup_subsys_state *cgrp_create(struct cgroup *cgrp) if (cgrp->parent && cgrp_netprio_state(cgrp->parent)->prioidx) goto out;
- ret = get_prioidx(&cs->prioidx); - if (ret < 0) { - pr_warn("No space in priority index array\n"); + cs->prioidx = ida_simple_get(&netprio_ida, 0, 0, GFP_KERNEL); + if (cs->prioidx < 0) { + ret = cs->prioidx; goto out; }
@@ -146,7 +115,7 @@ static void cgrp_destroy(struct cgroup *cgrp) map->priomap[cs->prioidx] = 0; } rtnl_unlock(); - put_prioidx(cs->prioidx); + ida_simple_remove(&netprio_ida, cs->prioidx); kfree(cs); }
@@ -284,12 +253,10 @@ struct cgroup_subsys net_prio_subsys = { .module = THIS_MODULE,
/* - * net_prio has artificial limit on the number of cgroups and - * disallows nesting making it impossible to co-mount it with other - * hierarchical subsystems. Remove the artificially low PRIOIDX_SZ - * limit and properly nest configuration such that children follow - * their parents' configurations by default and are allowed to - * override and remove the following. + * net_prio has artificial limit on properly nest + * configuration such that children follow their parents' + * configurations by default and are allowed to override and + * remove the following. */ .broken_hierarchy = true, }; -- 1.7.11.7
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