Messages in this thread | | | Date | Mon, 3 Aug 2009 01:18:28 +0900 (JST) | Subject | Re: memory-controller patch fails to boot in qemu [mmotm] | From | "KAMEZAWA Hiroyuki" <> |
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Hugh Dickins wrote: > 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>
nice fix, thank you very much.
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> --- > 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) >
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