lkml.org 
[lkml]   [2008]   [Nov]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Date
    Subject[mm] [PATCH 2/4] Memory cgroup resource counters for hierarchy (v4)

    Add support for building hierarchies in resource counters. Cgroups allows us
    to build a deep hierarchy, but we currently don't link the resource counters
    belonging to the memory controller control groups, in the same fashion
    as the corresponding cgroup entries in the cgroup hierarchy. This patch
    provides the infrastructure for resource counters that have the same hiearchy
    as their cgroup counter parts.

    These set of patches are based on the resource counter hiearchy patches posted
    by Pavel Emelianov.

    NOTE: Building hiearchies is expensive, deeper hierarchies imply charging
    the all the way up to the root. It is known that hiearchies are expensive,
    so the user needs to be careful and aware of the trade-offs before creating
    very deep ones.


    Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
    ---

    include/linux/res_counter.h | 8 ++++++--
    kernel/res_counter.c | 42 ++++++++++++++++++++++++++++++++++--------
    mm/memcontrol.c | 20 +++++++++++++-------
    3 files changed, 53 insertions(+), 17 deletions(-)

    diff -puN include/linux/res_counter.h~resource-counters-hierarchy-support include/linux/res_counter.h
    --- linux-2.6.28-rc4/include/linux/res_counter.h~resource-counters-hierarchy-support 2008-11-16 13:14:43.000000000 +0530
    +++ linux-2.6.28-rc4-balbir/include/linux/res_counter.h 2008-11-16 13:14:43.000000000 +0530
    @@ -43,6 +43,10 @@ struct res_counter {
    * the routines below consider this to be IRQ-safe
    */
    spinlock_t lock;
    + /*
    + * Parent counter, used for hierarchial resource accounting
    + */
    + struct res_counter *parent;
    };

    /**
    @@ -87,7 +91,7 @@ enum {
    * helpers for accounting
    */

    -void res_counter_init(struct res_counter *counter);
    +void res_counter_init(struct res_counter *counter, struct res_counter *parent);

    /*
    * charge - try to consume more resource.
    @@ -103,7 +107,7 @@ void res_counter_init(struct res_counter
    int __must_check res_counter_charge_locked(struct res_counter *counter,
    unsigned long val);
    int __must_check res_counter_charge(struct res_counter *counter,
    - unsigned long val);
    + unsigned long val, struct res_counter **limit_fail_at);

    /*
    * uncharge - tell that some portion of the resource is released
    diff -puN kernel/res_counter.c~resource-counters-hierarchy-support kernel/res_counter.c
    --- linux-2.6.28-rc4/kernel/res_counter.c~resource-counters-hierarchy-support 2008-11-16 13:14:43.000000000 +0530
    +++ linux-2.6.28-rc4-balbir/kernel/res_counter.c 2008-11-16 13:14:43.000000000 +0530
    @@ -15,10 +15,11 @@
    #include <linux/uaccess.h>
    #include <linux/mm.h>

    -void res_counter_init(struct res_counter *counter)
    +void res_counter_init(struct res_counter *counter, struct res_counter *parent)
    {
    spin_lock_init(&counter->lock);
    counter->limit = (unsigned long long)LLONG_MAX;
    + counter->parent = parent;
    }

    int res_counter_charge_locked(struct res_counter *counter, unsigned long val)
    @@ -34,14 +35,34 @@ int res_counter_charge_locked(struct res
    return 0;
    }

    -int res_counter_charge(struct res_counter *counter, unsigned long val)
    +int res_counter_charge(struct res_counter *counter, unsigned long val,
    + struct res_counter **limit_fail_at)
    {
    int ret;
    unsigned long flags;
    + struct res_counter *c, *u;

    - spin_lock_irqsave(&counter->lock, flags);
    - ret = res_counter_charge_locked(counter, val);
    - spin_unlock_irqrestore(&counter->lock, flags);
    + *limit_fail_at = NULL;
    + local_irq_save(flags);
    + for (c = counter; c != NULL; c = c->parent) {
    + spin_lock(&c->lock);
    + ret = res_counter_charge_locked(c, val);
    + spin_unlock(&c->lock);
    + if (ret < 0) {
    + *limit_fail_at = c;
    + goto undo;
    + }
    + }
    + ret = 0;
    + goto done;
    +undo:
    + for (u = counter; u != c; u = u->parent) {
    + spin_lock(&u->lock);
    + res_counter_uncharge_locked(u, val);
    + spin_unlock(&u->lock);
    + }
    +done:
    + local_irq_restore(flags);
    return ret;
    }

    @@ -56,10 +77,15 @@ void res_counter_uncharge_locked(struct
    void res_counter_uncharge(struct res_counter *counter, unsigned long val)
    {
    unsigned long flags;
    + struct res_counter *c;

    - spin_lock_irqsave(&counter->lock, flags);
    - res_counter_uncharge_locked(counter, val);
    - spin_unlock_irqrestore(&counter->lock, flags);
    + local_irq_save(flags);
    + for (c = counter; c != NULL; c = c->parent) {
    + spin_lock(&c->lock);
    + res_counter_uncharge_locked(c, val);
    + spin_unlock(&c->lock);
    + }
    + local_irq_restore(flags);
    }


    diff -puN mm/memcontrol.c~resource-counters-hierarchy-support mm/memcontrol.c
    --- linux-2.6.28-rc4/mm/memcontrol.c~resource-counters-hierarchy-support 2008-11-16 13:14:43.000000000 +0530
    +++ linux-2.6.28-rc4-balbir/mm/memcontrol.c 2008-11-16 13:14:43.000000000 +0530
    @@ -470,6 +470,7 @@ static int __mem_cgroup_try_charge(struc
    {
    struct mem_cgroup *mem;
    int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
    + struct res_counter *fail_res;
    /*
    * We always charge the cgroup the mm_struct belongs to.
    * The mm_struct's mem_cgroup changes on task migration if the
    @@ -498,11 +499,12 @@ static int __mem_cgroup_try_charge(struc
    int ret;
    bool noswap = false;

    - ret = res_counter_charge(&mem->res, PAGE_SIZE);
    + ret = res_counter_charge(&mem->res, PAGE_SIZE, &fail_res);
    if (likely(!ret)) {
    if (!do_swap_account)
    break;
    - ret = res_counter_charge(&mem->memsw, PAGE_SIZE);
    + ret = res_counter_charge(&mem->memsw, PAGE_SIZE,
    + &fail_res);
    if (likely(!ret))
    break;
    /* mem+swap counter fails */
    @@ -1687,22 +1689,26 @@ static void __init enable_swap_cgroup(vo
    static struct cgroup_subsys_state *
    mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
    {
    - struct mem_cgroup *mem;
    + struct mem_cgroup *mem, *parent;
    int node;

    mem = mem_cgroup_alloc();
    if (!mem)
    return ERR_PTR(-ENOMEM);

    - res_counter_init(&mem->res);
    - res_counter_init(&mem->memsw);
    -
    for_each_node_state(node, N_POSSIBLE)
    if (alloc_mem_cgroup_per_zone_info(mem, node))
    goto free_out;
    /* root ? */
    - if (cont->parent == NULL)
    + if (cont->parent == NULL) {
    enable_swap_cgroup();
    + parent = NULL;
    + } else
    + parent = mem_cgroup_from_cont(cont->parent);
    +
    + res_counter_init(&mem->res, parent ? &parent->res : NULL);
    + res_counter_init(&mem->memsw, parent ? &parent->memsw : NULL);
    +

    return &mem->css;
    free_out:
    _
    --
    Balbir


    \
     
     \ /
      Last update: 2008-11-16 09:13    [W:5.418 / U:0.004 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site