On 2024/12/18 2:19, Shakeel Butt wrote:
> On Fri, Dec 06, 2024 at 01:35:11AM +0000, Chen Ridong wrote:
>> From: Chen Ridong <chenridong@xxxxxxxxxx>
>>
>> Factor out the '__refill_obj_stock' function to make the code more
>> cohesive.
>>
>> Signed-off-by: Chen Ridong <chenridong@xxxxxxxxxx>
>> ---
>> mm/memcontrol.c | 31 ++++++++++++++++++-------------
>> 1 file changed, 18 insertions(+), 13 deletions(-)
>>
>> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
>> index f977e0be1c04..0c9331d7b606 100644
>> --- a/mm/memcontrol.c
>> +++ b/mm/memcontrol.c
>> @@ -2697,6 +2697,21 @@ void __memcg_kmem_uncharge_page(struct page *page, int order)
>> obj_cgroup_put(objcg);
>> }
>>
>> +/* If the cached_objcg was refilled, return true; otherwise, return false */
>> +static bool __refill_obj_stock(struct memcg_stock_pcp *stock,
>> + struct obj_cgroup *objcg, struct obj_cgroup **old_objcg)
>> +{
>> + if (READ_ONCE(stock->cached_objcg) != objcg) {
>
> Keep the above check in the calling functions and make this a void
> function. Also I think we need a better name.
>
Thank you for your review。
How about keeping the check in the calling functions and renaming like that:
/* Replace the stock objcg with objcg, return the old objcg */
static obj_cgroup *replace_stock_objcg (struct memcg_stock_pcp *stock,
struct obj_cgroup *objcg)
Best regards,
Ridong
>> + *old_objcg = drain_obj_stock(stock);
>> + obj_cgroup_get(objcg);
>> + stock->nr_bytes = atomic_read(&objcg->nr_charged_bytes)
>> + ? atomic_xchg(&objcg->nr_charged_bytes, 0) : 0;
>> + WRITE_ONCE(stock->cached_objcg, objcg);
>> + return true;
>> + }
>> + return false;
>> +}
>> +
>> static void mod_objcg_state(struct obj_cgroup *objcg, struct pglist_data *pgdat,
>> enum node_stat_item idx, int nr)
>> {
>> @@ -2713,12 +2728,7 @@ static void mod_objcg_state(struct obj_cgroup *objcg, struct pglist_data *pgdat,
>> * accumulating over a page of vmstat data or when pgdat or idx
>> * changes.
>> */
>> - if (READ_ONCE(stock->cached_objcg) != objcg) {
>> - old = drain_obj_stock(stock);
>> - obj_cgroup_get(objcg);
>> - stock->nr_bytes = atomic_read(&objcg->nr_charged_bytes)
>> - ? atomic_xchg(&objcg->nr_charged_bytes, 0) : 0;
>> - WRITE_ONCE(stock->cached_objcg, objcg);
>> + if (__refill_obj_stock(stock, objcg, &old)) {
>> stock->cached_pgdat = pgdat;
>> } else if (stock->cached_pgdat != pgdat) {
>> /* Flush the existing cached vmstat data */
>> @@ -2871,14 +2881,9 @@ static void refill_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes,
>> local_lock_irqsave(&memcg_stock.stock_lock, flags);
>>
>> stock = this_cpu_ptr(&memcg_stock);
>> - if (READ_ONCE(stock->cached_objcg) != objcg) { /* reset if necessary */
>> - old = drain_obj_stock(stock);
>> - obj_cgroup_get(objcg);
>> - WRITE_ONCE(stock->cached_objcg, objcg);
>> - stock->nr_bytes = atomic_read(&objcg->nr_charged_bytes)
>> - ? atomic_xchg(&objcg->nr_charged_bytes, 0) : 0;
>> + if (__refill_obj_stock(stock, objcg, &old))
>> allow_uncharge = true; /* Allow uncharge when objcg changes */
>> - }
>> +
>> stock->nr_bytes += nr_bytes;
>>
>> if (allow_uncharge && (stock->nr_bytes > PAGE_SIZE)) {
>> --
>> 2.34.1
>>
