diff options
author | Johannes Weiner <hannes@cmpxchg.org> | 2014-08-06 16:05:55 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-08-06 18:01:17 -0700 |
commit | 9476db974d9e18885123fcebc09f4596bb922e5f (patch) | |
tree | 70701f82e65c98a0ee5314d0eb3da9863e0f2091 /mm | |
parent | 0029e19ebf84dcd70b226820daa7747b28d5956d (diff) | |
download | linux-9476db974d9e18885123fcebc09f4596bb922e5f.tar.bz2 |
mm: memcontrol: simplify move precharge function
The move precharge function does some baroque things: it tries raw
res_counter charging of the entire amount first, and then falls back to
a loop of one-by-one charges, with checks for pending signals and
cond_resched() batching.
Just use mem_cgroup_try_charge() without __GFP_WAIT for the first bulk
charge attempt. In the one-by-one loop, remove the signal check (this
is already checked in try_charge), and simply call cond_resched() after
every charge - it's not that expensive.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r-- | mm/memcontrol.c | 48 |
1 files changed, 15 insertions, 33 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 8aaca8267dfe..8a4159efa3c0 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -6385,56 +6385,38 @@ static void mem_cgroup_css_reset(struct cgroup_subsys_state *css) #ifdef CONFIG_MMU /* Handlers for move charge at task migration. */ -#define PRECHARGE_COUNT_AT_ONCE 256 static int mem_cgroup_do_precharge(unsigned long count) { int ret = 0; - int batch_count = PRECHARGE_COUNT_AT_ONCE; - struct mem_cgroup *memcg = mc.to; - if (mem_cgroup_is_root(memcg)) { + if (mem_cgroup_is_root(mc.to)) { mc.precharge += count; /* we don't need css_get for root */ return ret; } - /* try to charge at once */ - if (count > 1) { - struct res_counter *dummy; - /* - * "memcg" cannot be under rmdir() because we've already checked - * by cgroup_lock_live_cgroup() that it is not removed and we - * are still under the same cgroup_mutex. So we can postpone - * css_get(). - */ - if (res_counter_charge(&memcg->res, PAGE_SIZE * count, &dummy)) - goto one_by_one; - if (do_swap_account && res_counter_charge(&memcg->memsw, - PAGE_SIZE * count, &dummy)) { - res_counter_uncharge(&memcg->res, PAGE_SIZE * count); - goto one_by_one; - } + + /* Try a single bulk charge without reclaim first */ + ret = mem_cgroup_try_charge(mc.to, GFP_KERNEL & ~__GFP_WAIT, count); + if (!ret) { mc.precharge += count; return ret; } -one_by_one: - /* fall back to one by one charge */ + + /* Try charges one by one with reclaim */ while (count--) { - if (signal_pending(current)) { - ret = -EINTR; - break; - } - if (!batch_count--) { - batch_count = PRECHARGE_COUNT_AT_ONCE; - cond_resched(); - } - ret = mem_cgroup_try_charge(memcg, + ret = mem_cgroup_try_charge(mc.to, GFP_KERNEL & ~__GFP_NORETRY, 1); + /* + * In case of failure, any residual charges against + * mc.to will be dropped by mem_cgroup_clear_mc() + * later on. + */ if (ret) - /* mem_cgroup_clear_mc() will do uncharge later */ return ret; mc.precharge++; + cond_resched(); } - return ret; + return 0; } /** |