[Devel] [PATCH vz9 v2] mm: per memory cgroup page cache limit
Pavel Tikhomirov
ptikhomirov at virtuozzo.com
Fri Jan 20 15:15:02 MSK 2023
On 20.01.2023 11:47, Alexander Atanasov wrote:
> From: Andrey Ryabinin <ryabinin.a.a at gmail.com>
>
> Forward port feature: mm: per memory cgroup page cache limit.
>
> The original implementation consisted of these commits:
> commit 758d52e33a67 ("configs: Enable CONFIG_PAGE_EXTENSION")
> commit 741beaa93c89 ("mm: introduce page vz extension (using page_ext)")
> commit d42d3c8b849d ("mm/memcg: limit page cache in memcg hack")
>
> This port drops the page vz extensions in favor of using a memcg_data
> bit to mark a page as cache. The benefit is that the implementation
> and porting got more simple. If we require new flags then the newly
> introduced folio can be used.
Why do you remove interface description? Please bring it back.
Feature exposes two files to set limit and to check usage at
/sys/fs/cgroup/memory/pagecache_limiter/memory.cache.limit_in_bytes
/sys/fs/cgroup/memory/pagecache_limiter/memory.cache.usage_in_bytes
and is enabled via /sys/fs/cgroup/memory/pagecache_limiter/tasks.
>
> https://jira.sw.ru/browse/PSBM-144609
> Signed-off-by: Alexander Atanasov <alexander.atanasov at virtuozzo.com>
> Signed-off-by: Andrey Ryabinin <ryabinin.a.a at gmail.com>
> ---
> include/linux/memcontrol.h | 29 ++++-
> mm/filemap.c | 3 +-
> mm/memcontrol.c | 219 ++++++++++++++++++++++++++++++-------
> 3 files changed, 207 insertions(+), 44 deletions(-)
>
> v1->v2: addressing Pavel's comments for v1
> - fixed compilation without MEMCG
> - try to preserve author
> - fixed line alignment
> - add missed bug traps and WARN_ONs
> - fixed spelling error
>
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index 561db06f1fd8..1a49416300c9 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -273,6 +273,7 @@ struct mem_cgroup {
> /* Legacy consumer-oriented counters */
> struct page_counter kmem; /* v1 only */
> struct page_counter tcpmem; /* v1 only */
> + struct page_counter cache;
>
> /* Range enforcement for interrupt charges */
> struct work_struct high_work;
> @@ -405,8 +406,10 @@ enum page_memcg_data_flags {
> MEMCG_DATA_OBJCGS = (1UL << 0),
> /* page has been accounted as a non-slab kernel page */
> MEMCG_DATA_KMEM = (1UL << 1),
> + /* page has been accounted as a cache page */
> + MEMCG_DATA_PGCACHE = (1UL << 2),
> /* the next bit after the last actual flag */
> - __NR_MEMCG_DATA_FLAGS = (1UL << 2),
> + __NR_MEMCG_DATA_FLAGS = (1UL << 3),
> };
>
> #define MEMCG_DATA_FLAGS_MASK (__NR_MEMCG_DATA_FLAGS - 1)
> @@ -771,11 +774,25 @@ int __mem_cgroup_charge(struct folio *folio, struct mm_struct *mm, gfp_t gfp);
> static inline int mem_cgroup_charge(struct folio *folio, struct mm_struct *mm,
> gfp_t gfp)
> {
> - if (mem_cgroup_disabled())
> - return 0;
> return __mem_cgroup_charge(folio, mm, gfp);
> }
>
> +int mem_cgroup_charge_cache(struct folio *folio, struct mm_struct *mm,
> + gfp_t gfp);
One more space here please.
> +
> +/*
> + * folio_memcg_cache - Check if the folio has the pgcache flag set.
> + * @folio: Pointer to the folio.
> + *
> + * Checks if the folio has page cache flag set. The caller must ensure
> + * that the folio has an associated memory cgroup. It's not safe to call
> + * this function against some types of folios, e.g. slab folios.
> + */
> +static inline bool folio_memcg_cache(struct folio *folio)
> +{
> + return folio->memcg_data & MEMCG_DATA_PGCACHE;
> +}
> +
> int mem_cgroup_swapin_charge_page(struct page *page, struct mm_struct *mm,
> gfp_t gfp, swp_entry_t entry);
> void mem_cgroup_swapin_uncharge_swap(swp_entry_t entry);
> @@ -1339,6 +1356,12 @@ static inline int mem_cgroup_charge(struct folio *folio,
> return 0;
> }
>
> +static inline int mem_cgroup_charge_cache(struct folio *folio,
> + struct mm_struct *mm, gfp_t gfp)
> +{
> + return 0;
> +}
> +
> static inline int mem_cgroup_swapin_charge_page(struct page *page,
> struct mm_struct *mm, gfp_t gfp, swp_entry_t entry)
> {
> diff --git a/mm/filemap.c b/mm/filemap.c
> index 2d63e53980e4..d568ffc0d416 100644
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -841,7 +841,8 @@ noinline int __filemap_add_folio(struct address_space *mapping,
> mapping_set_update(&xas, mapping);
>
> if (!huge) {
> - int error = mem_cgroup_charge(folio, NULL, gfp);
> + int error = mem_cgroup_charge_cache(folio, NULL, gfp);
> +
> VM_BUG_ON_FOLIO(index & (folio_nr_pages(folio) - 1), folio);
> if (error)
> return error;
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 6fa13539f3e5..6b462152e77f 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -218,6 +218,7 @@ enum res_type {
> _OOM_TYPE,
> _KMEM,
> _TCP,
> + _CACHE,
> };
>
> #define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val))
> @@ -2207,6 +2208,7 @@ struct memcg_stock_pcp {
> int nr_slab_unreclaimable_b;
> #endif
>
> + unsigned int cache_nr_pages;
> struct work_struct work;
> unsigned long flags;
> #define FLUSHING_CACHED_CHARGE 0
> @@ -2248,7 +2250,8 @@ static void memcg_account_kmem(struct mem_cgroup *memcg, int nr_pages)
> *
> * returns true if successful, false otherwise.
> */
> -static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
> +static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages,
> + bool cache)
> {
> struct memcg_stock_pcp *stock;
> unsigned long flags;
> @@ -2260,9 +2263,16 @@ static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
> local_lock_irqsave(&memcg_stock.stock_lock, flags);
>
> stock = this_cpu_ptr(&memcg_stock);
> - if (memcg == stock->cached && stock->nr_pages >= nr_pages) {
> - stock->nr_pages -= nr_pages;
> - ret = true;
> + if (memcg == stock->cached) {
> + if (cache && stock->cache_nr_pages >= nr_pages) {
> + stock->cache_nr_pages -= nr_pages;
> + ret = true;
> + }
> +
> + if (!cache && stock->nr_pages >= nr_pages) {
> + stock->nr_pages -= nr_pages;
> + ret = true;
> + }
> }
>
> local_unlock_irqrestore(&memcg_stock.stock_lock, flags);
> @@ -2276,15 +2286,20 @@ static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
> static void drain_stock(struct memcg_stock_pcp *stock)
> {
> struct mem_cgroup *old = stock->cached;
> + unsigned long nr_pages = stock->nr_pages + stock->cache_nr_pages;
>
> if (!old)
> return;
>
> - if (stock->nr_pages) {
> - page_counter_uncharge(&old->memory, stock->nr_pages);
> + if (stock->cache_nr_pages)
> + page_counter_uncharge(&old->cache, stock->cache_nr_pages);
> +
> + if (nr_pages) {
> + page_counter_uncharge(&old->memory, nr_pages);
> if (do_memsw_account())
> - page_counter_uncharge(&old->memsw, stock->nr_pages);
> + page_counter_uncharge(&old->memsw, nr_pages);
> stock->nr_pages = 0;
> + stock->cache_nr_pages = 0;
> }
>
> css_put(&old->css);
> @@ -2318,9 +2333,11 @@ static void drain_local_stock(struct work_struct *dummy)
> * Cache charges(val) to local per_cpu area.
> * This will be consumed by consume_stock() function, later.
> */
> -static void __refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
> +static void __refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages,
> + bool cache)
> {
> struct memcg_stock_pcp *stock;
> + unsigned long stock_nr_pages;
>
> stock = this_cpu_ptr(&memcg_stock);
> if (stock->cached != memcg) { /* reset if necessary */
> @@ -2328,18 +2345,23 @@ static void __refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
> css_get(&memcg->css);
> stock->cached = memcg;
> }
> - stock->nr_pages += nr_pages;
> + if (!cache)
> + stock->nr_pages += nr_pages;
> + else
> + stock->cache_nr_pages += nr_pages;
>
> - if (stock->nr_pages > MEMCG_CHARGE_BATCH)
> + stock_nr_pages = stock->nr_pages + stock->cache_nr_pages;
> + if (stock_nr_pages > MEMCG_CHARGE_BATCH)
> drain_stock(stock);
> }
>
> -static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
> +static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages,
> + bool cache)
> {
> unsigned long flags;
>
> local_lock_irqsave(&memcg_stock.stock_lock, flags);
> - __refill_stock(memcg, nr_pages);
> + __refill_stock(memcg, nr_pages, cache);
> local_unlock_irqrestore(&memcg_stock.stock_lock, flags);
> }
>
> @@ -2366,10 +2388,12 @@ static void drain_all_stock(struct mem_cgroup *root_memcg)
> struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
> struct mem_cgroup *memcg;
> bool flush = false;
> + unsigned long nr_pages = stock->nr_pages +
> + stock->cache_nr_pages;
>
> rcu_read_lock();
> memcg = stock->cached;
> - if (memcg && stock->nr_pages &&
> + if (memcg && nr_pages &&
> mem_cgroup_is_descendant(memcg, root_memcg))
> flush = true;
> else if (obj_stock_flush_required(stock, root_memcg))
> @@ -2406,17 +2430,27 @@ static unsigned long reclaim_high(struct mem_cgroup *memcg,
>
> do {
> unsigned long pflags;
> + long cache_overused;
>
> - if (page_counter_read(&memcg->memory) <=
> - READ_ONCE(memcg->memory.high))
> - continue;
> + if (page_counter_read(&memcg->memory) >
> + READ_ONCE(memcg->memory.high)) {
> + memcg_memory_event(memcg, MEMCG_HIGH);
> +
> + psi_memstall_enter(&pflags);
> + nr_reclaimed += try_to_free_mem_cgroup_pages(memcg,
> + nr_pages, gfp_mask, true);
> + psi_memstall_leave(&pflags);
> + }
>
> - memcg_memory_event(memcg, MEMCG_HIGH);
> + cache_overused = page_counter_read(&memcg->cache) -
> + memcg->cache.max;
>
> - psi_memstall_enter(&pflags);
> - nr_reclaimed += try_to_free_mem_cgroup_pages(memcg, nr_pages,
> - gfp_mask, true);
> - psi_memstall_leave(&pflags);
> + if (cache_overused > 0) {
> + psi_memstall_enter(&pflags);
> + nr_reclaimed += try_to_free_mem_cgroup_pages(memcg,
> + cache_overused, gfp_mask, false);
> + psi_memstall_leave(&pflags);
> + }
> } while ((memcg = parent_mem_cgroup(memcg)) &&
> !mem_cgroup_is_root(memcg));
>
> @@ -2652,7 +2686,7 @@ void mem_cgroup_handle_over_high(void)
> }
>
> static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask,
> - unsigned int nr_pages)
> + unsigned int nr_pages, bool cache_charge)
Also one more space.
> {
> unsigned int batch = max(MEMCG_CHARGE_BATCH, nr_pages);
> int nr_retries = MAX_RECLAIM_RETRIES;
> @@ -2666,8 +2700,8 @@ static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask,
> unsigned long pflags;
>
> retry:
> - if (consume_stock(memcg, nr_pages))
> - return 0;
> + if (consume_stock(memcg, nr_pages, cache_charge))
> + goto done;
>
> if (!do_memsw_account() ||
> page_counter_try_charge(&memcg->memsw, batch, &counter)) {
> @@ -2780,13 +2814,19 @@ static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask,
> page_counter_charge(&memcg->memory, nr_pages);
> if (do_memsw_account())
> page_counter_charge(&memcg->memsw, nr_pages);
> + if (cache_charge)
> + page_counter_charge(&memcg->cache, nr_pages);
>
> return 0;
>
> done_restock:
> + if (cache_charge)
> + page_counter_charge(&memcg->cache, batch);
> +
> if (batch > nr_pages)
> - refill_stock(memcg, batch - nr_pages);
> + refill_stock(memcg, batch - nr_pages, cache_charge);
>
> +done:
> /*
> * If the hierarchy is above the normal consumption range, schedule
> * reclaim on returning to userland. We can perform reclaim here
> @@ -2826,6 +2866,9 @@ static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask,
> current->memcg_nr_pages_over_high += batch;
> set_notify_resume(current);
> break;
> + } else if (page_counter_read(&memcg->cache) > memcg->cache.max) {
> + if (!work_pending(&memcg->high_work))
> + schedule_work(&memcg->high_work);
> }
> } while ((memcg = parent_mem_cgroup(memcg)));
>
> @@ -2833,12 +2876,12 @@ static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask,
> }
>
> static inline int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
> - unsigned int nr_pages)
> + unsigned int nr_pages, bool cache_charge)
> {
> if (mem_cgroup_is_root(memcg))
> return 0;
>
> - return try_charge_memcg(memcg, gfp_mask, nr_pages);
> + return try_charge_memcg(memcg, gfp_mask, nr_pages, cache_charge);
> }
>
> static inline void cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages)
> @@ -3024,7 +3067,7 @@ static void obj_cgroup_uncharge_pages(struct obj_cgroup *objcg,
> memcg = get_mem_cgroup_from_objcg(objcg);
>
> memcg_account_kmem(memcg, -nr_pages);
> - refill_stock(memcg, nr_pages);
> + refill_stock(memcg, nr_pages, false);
>
> css_put(&memcg->css);
> }
> @@ -3045,7 +3088,7 @@ static int obj_cgroup_charge_pages(struct obj_cgroup *objcg, gfp_t gfp,
>
> memcg = get_mem_cgroup_from_objcg(objcg);
>
> - ret = try_charge_memcg(memcg, gfp, nr_pages);
> + ret = try_charge_memcg(memcg, gfp, nr_pages, false);
> if (ret)
> goto out;
>
> @@ -3204,7 +3247,7 @@ static struct obj_cgroup *drain_obj_stock(struct memcg_stock_pcp *stock)
> memcg = get_mem_cgroup_from_objcg(old);
>
> memcg_account_kmem(memcg, -nr_pages);
> - __refill_stock(memcg, nr_pages);
> + __refill_stock(memcg, nr_pages, false);
>
> css_put(&memcg->css);
> }
> @@ -3352,7 +3395,7 @@ int memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp,
> {
> int ret = 0;
>
> - ret = try_charge(memcg, gfp, nr_pages);
> + ret = try_charge(memcg, gfp, nr_pages, false);
> if (!ret)
> page_counter_charge(&memcg->kmem, nr_pages);
>
> @@ -3711,6 +3754,9 @@ static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css,
> case _TCP:
> counter = &memcg->tcpmem;
> break;
> + case _CACHE:
> + counter = &memcg->cache;
> + break;
> default:
> BUG();
> }
> @@ -3829,6 +3875,43 @@ static int memcg_update_tcp_max(struct mem_cgroup *memcg, unsigned long max)
> return ret;
> }
>
> +static int memcg_update_cache_max(struct mem_cgroup *memcg,
> + unsigned long limit)
Same.
> +{
> + unsigned long nr_pages;
> + bool enlarge = false;
> + int ret;
> +
> + do {
> + if (signal_pending(current)) {
> + ret = -EINTR;
> + break;
> + }
> + mutex_lock(&memcg_max_mutex);
> +
> + if (limit > memcg->cache.max)
> + enlarge = true;
> +
> + ret = page_counter_set_max(&memcg->cache, limit);
> + mutex_unlock(&memcg_max_mutex);
> +
> + if (!ret)
> + break;
> +
> + nr_pages = max_t(long, 1, page_counter_read(&memcg->cache) - limit);
> + if (!try_to_free_mem_cgroup_pages(memcg, nr_pages,
> + GFP_KERNEL, false)) {
> + ret = -EBUSY;
> + break;
> + }
> + } while (1);
> +
> + if (!ret && enlarge)
> + memcg_oom_recover(memcg);
> +
> + return ret;
> +}
> +
> /*
> * The user of this function is...
> * RES_LIMIT.
> @@ -3865,6 +3948,9 @@ static ssize_t mem_cgroup_write(struct kernfs_open_file *of,
> case _TCP:
> ret = memcg_update_tcp_max(memcg, nr_pages);
> break;
> + case _CACHE:
> + ret = memcg_update_cache_max(memcg, nr_pages);
> + break;
> }
> break;
> case RES_SOFT_LIMIT:
> @@ -3898,6 +3984,9 @@ static ssize_t mem_cgroup_reset(struct kernfs_open_file *of, char *buf,
> case _TCP:
> counter = &memcg->tcpmem;
> break;
> + case _CACHE:
> + counter = &memcg->cache;
> + break;
> default:
> BUG();
> }
> @@ -5541,6 +5630,17 @@ static struct cftype mem_cgroup_legacy_files[] = {
> {
> .name = "pressure_level",
> },
> + {
> + .name = "cache.limit_in_bytes",
> + .private = MEMFILE_PRIVATE(_CACHE, RES_LIMIT),
> + .write = mem_cgroup_write,
> + .read_u64 = mem_cgroup_read_u64,
> + },
> + {
> + .name = "cache.usage_in_bytes",
> + .private = MEMFILE_PRIVATE(_CACHE, RES_USAGE),
> + .read_u64 = mem_cgroup_read_u64,
> + },
> #ifdef CONFIG_NUMA
> {
> .name = "numa_stat",
> @@ -5825,11 +5925,13 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
> page_counter_init(&memcg->swap, &parent->swap);
> page_counter_init(&memcg->kmem, &parent->kmem);
> page_counter_init(&memcg->tcpmem, &parent->tcpmem);
> + page_counter_init(&memcg->cache, &parent->cache);
> } else {
> page_counter_init(&memcg->memory, NULL);
> page_counter_init(&memcg->swap, NULL);
> page_counter_init(&memcg->kmem, NULL);
> page_counter_init(&memcg->tcpmem, NULL);
> + page_counter_init(&memcg->cache, NULL);
>
> root_mem_cgroup = memcg;
> return &memcg->css;
> @@ -5950,6 +6052,7 @@ static void mem_cgroup_css_reset(struct cgroup_subsys_state *css)
> page_counter_set_max(&memcg->swap, PAGE_COUNTER_MAX);
> page_counter_set_max(&memcg->kmem, PAGE_COUNTER_MAX);
> page_counter_set_max(&memcg->tcpmem, PAGE_COUNTER_MAX);
> + page_counter_set_max(&memcg->cache, PAGE_COUNTER_MAX);
> page_counter_set_min(&memcg->memory, 0);
> page_counter_set_low(&memcg->memory, 0);
> page_counter_set_high(&memcg->memory, PAGE_COUNTER_MAX);
> @@ -6051,7 +6154,8 @@ static int mem_cgroup_do_precharge(unsigned long count)
> int ret;
>
> /* Try a single bulk charge without reclaim first, kswapd may wake */
> - ret = try_charge(mc.to, GFP_KERNEL & ~__GFP_DIRECT_RECLAIM, count);
> + ret = try_charge(mc.to, GFP_KERNEL & ~__GFP_DIRECT_RECLAIM, count,
> + false);
> if (!ret) {
> mc.precharge += count;
> return ret;
> @@ -6059,7 +6163,7 @@ static int mem_cgroup_do_precharge(unsigned long count)
>
> /* Try charges one by one with reclaim, but do not retry */
> while (count--) {
> - ret = try_charge(mc.to, GFP_KERNEL | __GFP_NORETRY, 1);
> + ret = try_charge(mc.to, GFP_KERNEL | __GFP_NORETRY, 1, false);
> if (ret)
> return ret;
> mc.precharge++;
> @@ -7285,18 +7389,27 @@ void mem_cgroup_calculate_protection(struct mem_cgroup *root,
> }
>
> static int charge_memcg(struct folio *folio, struct mem_cgroup *memcg,
> - gfp_t gfp)
> + gfp_t gfp, bool cache_charge)
> {
> long nr_pages = folio_nr_pages(folio);
> int ret;
>
> - ret = try_charge(memcg, gfp, nr_pages);
> + ret = try_charge(memcg, gfp, nr_pages, cache_charge);
> if (ret)
> goto out;
>
> css_get(&memcg->css);
> commit_charge(folio, memcg);
>
> + /*
> + * We always cleanup this flag on uncharging, it means
> + * that during charging we shouldn't have this flag set
> + */
> +
> + VM_BUG_ON(folio_memcg_cache(folio));
> + if (cache_charge)
> + WRITE_ONCE(folio->memcg_data,
> + READ_ONCE(folio->memcg_data) | MEMCG_DATA_PGCACHE);
> local_irq_disable();
> mem_cgroup_charge_statistics(memcg, nr_pages);
> memcg_check_events(memcg, folio_nid(folio));
> @@ -7305,18 +7418,32 @@ static int charge_memcg(struct folio *folio, struct mem_cgroup *memcg,
> return ret;
> }
>
> -int __mem_cgroup_charge(struct folio *folio, struct mm_struct *mm, gfp_t gfp)
> +static int __mem_cgroup_charge_gen(struct folio *folio, struct mm_struct *mm,
> + gfp_t gfp_mask, bool cache_charge)
> {
> struct mem_cgroup *memcg;
> int ret;
>
> + if (mem_cgroup_disabled())
> + return 0;
> +
> memcg = get_mem_cgroup_from_mm(mm);
> - ret = charge_memcg(folio, memcg, gfp);
> + ret = charge_memcg(folio, memcg, gfp_mask, cache_charge);
> css_put(&memcg->css);
>
> return ret;
> }
>
> +int __mem_cgroup_charge(struct folio *folio, struct mm_struct *mm, gfp_t gfp)
> +{
> + return __mem_cgroup_charge_gen(folio, mm, gfp, false);
> +}
> +
> +int mem_cgroup_charge_cache(struct folio *folio, struct mm_struct *mm, gfp_t gfp)
> +{
> + return __mem_cgroup_charge_gen(folio, mm, gfp, true);
> +}
> +
> /**
> * mem_cgroup_swapin_charge_page - charge a newly allocated page for swapin
> * @page: page to charge
> @@ -7347,7 +7474,7 @@ int mem_cgroup_swapin_charge_page(struct page *page, struct mm_struct *mm,
> memcg = get_mem_cgroup_from_mm(mm);
> rcu_read_unlock();
>
> - ret = charge_memcg(folio, memcg, gfp);
> + ret = charge_memcg(folio, memcg, gfp, false);
>
> css_put(&memcg->css);
> return ret;
> @@ -7391,6 +7518,7 @@ struct uncharge_gather {
> unsigned long nr_memory;
> unsigned long pgpgout;
> unsigned long nr_kmem;
> + unsigned long nr_pgcache;
> int nid;
> };
>
> @@ -7409,6 +7537,9 @@ static void uncharge_batch(const struct uncharge_gather *ug)
> page_counter_uncharge(&ug->memcg->memsw, ug->nr_memory);
> if (ug->nr_kmem)
> memcg_account_kmem(ug->memcg, -ug->nr_kmem);
> + if (ug->nr_pgcache)
> + page_counter_uncharge(&ug->memcg->cache, ug->nr_pgcache);
> +
> memcg_oom_recover(ug->memcg);
> }
>
> @@ -7470,6 +7601,8 @@ static void uncharge_folio(struct folio *folio, struct uncharge_gather *ug)
> folio->memcg_data = 0;
> obj_cgroup_put(objcg);
> } else {
> + if (folio_memcg_cache(folio))
> + ug->nr_pgcache += nr_pages;
> /* LRU pages aren't accounted at the root level */
> if (!mem_cgroup_is_root(memcg))
> ug->nr_memory += nr_pages;
> @@ -7553,6 +7686,12 @@ void mem_cgroup_migrate(struct folio *old, struct folio *new)
> page_counter_charge(&memcg->memsw, nr_pages);
> }
>
> + WARN_ON((!PageAnon(&new->page) && !PageSwapBacked(&new->page)) |
> + folio_memcg_cache(new));
It was in the original patch:
+ WARN_ON((!PageAnon(newpage) && !PageSwapBacked(newpage)) !=
+ PageVzPageCache(newpage));
meaning that we check that pages marked as page cache are not anon and
not swap and vice versa. When you change "!=" to "|" now all pages
marked as page cache or non-anon-non-swap woutl trigger this warning.
> +
> + if (folio_memcg_cache(new))
> + page_counter_charge(&memcg->cache, nr_pages);
> +
> css_get(&memcg->css);
> commit_charge(new, memcg);
>
> @@ -7621,7 +7760,7 @@ bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages,
> return false;
> }
>
> - if (try_charge(memcg, gfp_mask, nr_pages) == 0) {
> + if (try_charge(memcg, gfp_mask, nr_pages, false) == 0) {
> mod_memcg_state(memcg, MEMCG_SOCK, nr_pages);
> return true;
> }
> @@ -7643,7 +7782,7 @@ void mem_cgroup_uncharge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages)
>
> mod_memcg_state(memcg, MEMCG_SOCK, -nr_pages);
>
> - refill_stock(memcg, nr_pages);
> + refill_stock(memcg, nr_pages, false);
> }
>
> static int __init cgroup_memory(char *s)
--
Best regards, Tikhomirov Pavel
Software Developer, Virtuozzo.
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