From: Sergey Senozhatsky <senozhatsky@chromium.org>
To: Chengming Zhou <zhouchengming@bytedance.com>
Cc: yosryahmed@google.com,
Sergey Senozhatsky <senozhatsky@chromium.org>,
hannes@cmpxchg.org, nphamcs@gmail.com,
Andrew Morton <akpm@linux-foundation.org>,
Minchan Kim <minchan@kernel.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 1/2] mm/zsmalloc: don't hold locks of all pages when free_zspage()
Date: Wed, 28 Feb 2024 15:01:13 +0900 [thread overview]
Message-ID: <20240228060113.GJ11972@google.com> (raw)
In-Reply-To: <20240226-zsmalloc-zspage-rcu-v1-1-456b0ef1a89d@bytedance.com>
On (24/02/27 03:02), Chengming Zhou wrote:
> static void __free_zspage(struct zs_pool *pool, struct size_class *class,
> struct zspage *zspage)
> {
> @@ -834,13 +841,12 @@ static void __free_zspage(struct zs_pool *pool, struct size_class *class,
> VM_BUG_ON_PAGE(!PageLocked(page), page);
Who owns page lock here if free_zspage() doesn't trylock_zspage() no longer?
> next = get_next_page(page);
> reset_page(page);
> - unlock_page(page);
> dec_zone_page_state(page, NR_ZSPAGES);
> put_page(page);
> page = next;
> } while (page != NULL);
>
> - cache_free_zspage(pool, zspage);
> + call_rcu(&zspage->rcu_head, rcu_free_zspage);
>
> class_stat_dec(class, ZS_OBJS_ALLOCATED, class->objs_per_zspage);
> atomic_long_sub(class->pages_per_zspage, &pool->pages_allocated);
> @@ -852,16 +858,6 @@ static void free_zspage(struct zs_pool *pool, struct size_class *class,
> VM_BUG_ON(get_zspage_inuse(zspage));
> VM_BUG_ON(list_empty(&zspage->list));
>
> - /*
> - * Since zs_free couldn't be sleepable, this function cannot call
> - * lock_page. The page locks trylock_zspage got will be released
> - * by __free_zspage.
> - */
> - if (!trylock_zspage(zspage)) {
> - kick_deferred_free(pool);
> - return;
> - }
> -
> remove_zspage(class, zspage);
> __free_zspage(pool, class, zspage);
> }
next prev parent reply other threads:[~2024-02-28 6:01 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-27 3:02 [PATCH 0/2] mm/zsmalloc: simplify synchronization between zs_page_migrate() and free_zspage() Chengming Zhou
2024-02-27 3:02 ` [PATCH 1/2] mm/zsmalloc: don't hold locks of all pages when free_zspage() Chengming Zhou
2024-02-28 4:33 ` Sergey Senozhatsky
2024-02-28 5:14 ` Chengming Zhou
2024-02-28 5:29 ` Sergey Senozhatsky
2024-02-28 5:42 ` Chengming Zhou
2024-02-28 6:07 ` Sergey Senozhatsky
2024-02-28 6:01 ` Sergey Senozhatsky [this message]
2024-02-28 6:44 ` Chengming Zhou
2024-02-28 6:14 ` Sergey Senozhatsky
2024-02-28 6:49 ` Chengming Zhou
2024-02-27 3:02 ` [PATCH 2/2] mm/zsmalloc: remove the deferred free mechanism Chengming Zhou
2024-02-28 1:57 ` [PATCH 0/2] mm/zsmalloc: simplify synchronization between zs_page_migrate() and free_zspage() Sergey Senozhatsky
2024-02-28 2:22 ` [External] " Chengming Zhou
2024-02-28 3:54 ` Sergey Senozhatsky
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