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>
This commit is contained in:
parent
0029e19ebf
commit
9476db974d
1 changed files with 15 additions and 33 deletions
|
@ -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;
|
||||
}
|
||||
|
||||
/**
|
||||
|
|
Loading…
Reference in a new issue