On Thu 29-05-14 12:15:53, Johannes Weiner wrote: > This function was split out because mem_cgroup_try_charge() got too > big. But having essentially one sequence of operations arbitrarily > split in half is not good for reworking the code. Fold it back in. > > Signed-off-by: Johannes Weiner <[email protected]>
Acked-by: Michal Hocko <[email protected]> > --- > mm/memcontrol.c | 166 > ++++++++++++++++++++++---------------------------------- > 1 file changed, 64 insertions(+), 102 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 4df733e13727..c3c10ab98355 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -2552,80 +2552,6 @@ static int memcg_cpu_hotplug_callback(struct > notifier_block *nb, > return NOTIFY_OK; > } > > - > -/* See mem_cgroup_try_charge() for details */ > -enum { > - CHARGE_OK, /* success */ > - CHARGE_RETRY, /* need to retry but retry is not bad */ > - CHARGE_NOMEM, /* we can't do more. return -ENOMEM */ > - CHARGE_WOULDBLOCK, /* GFP_WAIT wasn't set and no enough res. */ > -}; > - > -static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask, > - unsigned int nr_pages, unsigned int min_pages, > - bool invoke_oom) > -{ > - unsigned long csize = nr_pages * PAGE_SIZE; > - struct mem_cgroup *mem_over_limit; > - struct res_counter *fail_res; > - unsigned long flags = 0; > - int ret; > - > - ret = res_counter_charge(&memcg->res, csize, &fail_res); > - > - if (likely(!ret)) { > - if (!do_swap_account) > - return CHARGE_OK; > - ret = res_counter_charge(&memcg->memsw, csize, &fail_res); > - if (likely(!ret)) > - return CHARGE_OK; > - > - res_counter_uncharge(&memcg->res, csize); > - mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw); > - flags |= MEM_CGROUP_RECLAIM_NOSWAP; > - } else > - mem_over_limit = mem_cgroup_from_res_counter(fail_res, res); > - /* > - * Never reclaim on behalf of optional batching, retry with a > - * single page instead. > - */ > - if (nr_pages > min_pages) > - return CHARGE_RETRY; > - > - if (!(gfp_mask & __GFP_WAIT)) > - return CHARGE_WOULDBLOCK; > - > - if (gfp_mask & __GFP_NORETRY) > - return CHARGE_NOMEM; > - > - ret = mem_cgroup_reclaim(mem_over_limit, gfp_mask, flags); > - if (mem_cgroup_margin(mem_over_limit) >= nr_pages) > - return CHARGE_RETRY; > - /* > - * Even though the limit is exceeded at this point, reclaim > - * may have been able to free some pages. Retry the charge > - * before killing the task. > - * > - * Only for regular pages, though: huge pages are rather > - * unlikely to succeed so close to the limit, and we fall back > - * to regular pages anyway in case of failure. > - */ > - if (nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER) && ret) > - return CHARGE_RETRY; > - > - /* > - * At task move, charge accounts can be doubly counted. So, it's > - * better to wait until the end of task_move if something is going on. > - */ > - if (mem_cgroup_wait_acct_move(mem_over_limit)) > - return CHARGE_RETRY; > - > - if (invoke_oom) > - mem_cgroup_oom(mem_over_limit, gfp_mask, get_order(csize)); > - > - return CHARGE_NOMEM; > -} > - > /** > * mem_cgroup_try_charge - try charging a memcg > * @memcg: memcg to charge > @@ -2642,7 +2568,11 @@ static int mem_cgroup_try_charge(struct mem_cgroup > *memcg, > { > unsigned int batch = max(CHARGE_BATCH, nr_pages); > int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES; > - int ret; > + struct mem_cgroup *mem_over_limit; > + struct res_counter *fail_res; > + unsigned long nr_reclaimed; > + unsigned long flags = 0; > + unsigned long long size; > > if (mem_cgroup_is_root(memcg)) > goto done; > @@ -2662,44 +2592,76 @@ static int mem_cgroup_try_charge(struct mem_cgroup > *memcg, > > if (gfp_mask & __GFP_NOFAIL) > oom = false; > -again: > +retry: > if (consume_stock(memcg, nr_pages)) > goto done; > > - do { > - bool invoke_oom = oom && !nr_oom_retries; > + size = batch * PAGE_SIZE; > + if (!res_counter_charge(&memcg->res, size, &fail_res)) { > + if (!do_swap_account) > + goto done_restock; > + if (!res_counter_charge(&memcg->memsw, size, &fail_res)) > + goto done_restock; > + res_counter_uncharge(&memcg->res, size); > + mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw); > + flags |= MEM_CGROUP_RECLAIM_NOSWAP; > + } else > + mem_over_limit = mem_cgroup_from_res_counter(fail_res, res); > > - /* If killed, bypass charge */ > - if (fatal_signal_pending(current)) > - goto bypass; > + if (batch > nr_pages) { > + batch = nr_pages; > + goto retry; > + } > > - ret = mem_cgroup_do_charge(memcg, gfp_mask, batch, > - nr_pages, invoke_oom); > - switch (ret) { > - case CHARGE_OK: > - break; > - case CHARGE_RETRY: /* not in OOM situation but retry */ > - batch = nr_pages; > - goto again; > - case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */ > - goto nomem; > - case CHARGE_NOMEM: /* OOM routine works */ > - if (!oom || invoke_oom) > - goto nomem; > - nr_oom_retries--; > - break; > - } > - } while (ret != CHARGE_OK); > + if (!(gfp_mask & __GFP_WAIT)) > + goto nomem; > > - if (batch > nr_pages) > - refill_stock(memcg, batch - nr_pages); > -done: > - return 0; > + if (gfp_mask & __GFP_NORETRY) > + goto nomem; > + > + nr_reclaimed = mem_cgroup_reclaim(mem_over_limit, gfp_mask, flags); > + > + if (mem_cgroup_margin(mem_over_limit) >= batch) > + goto retry; > + /* > + * Even though the limit is exceeded at this point, reclaim > + * may have been able to free some pages. Retry the charge > + * before killing the task. > + * > + * Only for regular pages, though: huge pages are rather > + * unlikely to succeed so close to the limit, and we fall back > + * to regular pages anyway in case of failure. > + */ > + if (nr_reclaimed && batch <= (1 << PAGE_ALLOC_COSTLY_ORDER)) > + goto retry; > + /* > + * At task move, charge accounts can be doubly counted. So, it's > + * better to wait until the end of task_move if something is going on. > + */ > + if (mem_cgroup_wait_acct_move(mem_over_limit)) > + goto retry; > + > + if (fatal_signal_pending(current)) > + goto bypass; > + > + if (!oom) > + goto nomem; > + > + if (nr_oom_retries--) > + goto retry; > + > + mem_cgroup_oom(mem_over_limit, gfp_mask, get_order(batch)); > nomem: > if (!(gfp_mask & __GFP_NOFAIL)) > return -ENOMEM; > bypass: > return -EINTR; > + > +done_restock: > + if (batch > nr_pages) > + refill_stock(memcg, batch - nr_pages); > +done: > + return 0; > } > > /** > -- > 1.9.3 > -- Michal Hocko SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
