Messages in this thread Patch in this message | | | Date | Sun, 2 Aug 2009 17:12:53 +0100 (BST) | From | Hugh Dickins <> | Subject | Re: memory-controller patch fails to boot in qemu [mmotm] |
| |
On Sun, 2 Aug 2009, Balbir Singh wrote: > * Hugh Dickins <hugh.dickins@tiscali.co.uk> [2009-08-01 23:09:09]: > > > > Hmm, this a weird function, passed an argument just to tell it to do > > nothing. Perhaps a placeholder for something more sensible to come? > > The argument is passed a result of a function, It no-ops quite > frequently for the root cgroup.
The more often it no-ops, the sillier it is to be called in the first place: here's an updated patch which fixes that too.
[PATCH mmotm] memory controller: soft limit organize cgroups v9 fix
CONFIG_CGROUP_MEM_RES_CTLR=y CONFIG_PREEMPT=y mmotm fails to boot: Kernel panic - not syncing: No init found; after lots of scheduling while atomics, starting from when async_thread does sd_probe_async.
mem_cgroup_soft_limit_check() was doing an unbalanced get_cpu(): don't get_cpu if we won't need it, and put_cpu if we did get_cpu.
And fix the silliness of passing it an "over_soft_limit" argument that just tells it to return false when false.
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> --- Fix to memory-controller-soft-limit-organize-cgroups-v9.patch
mm/memcontrol.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-)
--- mmotm/mm/memcontrol.c 2009-08-01 05:48:08.000000000 +0100 +++ linux/mm/memcontrol.c 2009-08-02 16:56:02.000000000 +0100 @@ -371,23 +371,21 @@ mem_cgroup_remove_exceeded(struct mem_cg spin_unlock(&mctz->lock); } -static bool mem_cgroup_soft_limit_check(struct mem_cgroup *mem, - bool over_soft_limit) +static bool mem_cgroup_soft_limit_check(struct mem_cgroup *mem) { bool ret = false; - int cpu = get_cpu(); + int cpu; s64 val; struct mem_cgroup_stat_cpu *cpustat; - if (!over_soft_limit) - return ret; - + cpu = get_cpu(); cpustat = &mem->stat.cpustat[cpu]; val = __mem_cgroup_stat_read_local(cpustat, MEM_CGROUP_STAT_EVENTS); if (unlikely(val > SOFTLIMIT_EVENTS_THRESH)) { __mem_cgroup_stat_reset_safe(cpustat, MEM_CGROUP_STAT_EVENTS); ret = true; } + put_cpu(); return ret; } @@ -1342,7 +1340,7 @@ static int __mem_cgroup_try_charge(struc if (soft_fail_res) { mem_over_soft_limit = mem_cgroup_from_res_counter(soft_fail_res, res); - if (mem_cgroup_soft_limit_check(mem_over_soft_limit, true)) + if (mem_cgroup_soft_limit_check(mem_over_soft_limit)) mem_cgroup_update_tree(mem_over_soft_limit, page); } return 0; @@ -1873,7 +1871,7 @@ __mem_cgroup_uncharge_common(struct page mz = page_cgroup_zoneinfo(pc); unlock_page_cgroup(pc); - if (mem_cgroup_soft_limit_check(mem, soft_limit_excess)) + if (soft_limit_excess && mem_cgroup_soft_limit_check(mem)) mem_cgroup_update_tree(mem, page); /* at swapout, this memcg will be accessed to record to swap */ if (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
| |