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Tue, 12 May 2026 02:38:02 -0700 (PDT) Message-ID: <46eb7e35-0f8e-e667-1f86-f518fe699378@gmail.com> Date: Tue, 12 May 2026 17:37:51 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.15.0 Subject: Re: [PATCH 2/3] mm/zswap: Implement proactive writeback To: Nhat Pham Cc: akpm@linux-foundation.org, tj@kernel.org, hannes@cmpxchg.org, shakeel.butt@linux.dev, mhocko@kernel.org, yosry@kernel.org, mkoutny@suse.com, chengming.zhou@linux.dev, muchun.song@linux.dev, roman.gushchin@linux.dev, cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, Hao Jia References: <20260511105149.75584-1-jiahao.kernel@gmail.com> <20260511105149.75584-3-jiahao.kernel@gmail.com> From: Hao Jia In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 2026/5/12 03:54, Nhat Pham wrote: > On Mon, May 11, 2026 at 3:52 AM Hao Jia wrote: >> diff --git a/mm/zswap.c b/mm/zswap.c >> index 19538d6f169a..1173ac6836fa 100644 >> --- a/mm/zswap.c >> +++ b/mm/zswap.c >> @@ -36,6 +36,7 @@ >> #include >> #include >> #include >> +#include >> >> #include "swap.h" >> #include "internal.h" >> @@ -160,6 +161,12 @@ struct zswap_pool { >> char tfm_name[CRYPTO_MAX_ALG_NAME]; >> }; >> >> +struct zswap_shrink_walk_arg { >> + ktime_t cutoff_time; >> + bool proactive; >> + bool encountered_page_in_swapcache; >> +}; >> + >> /* Global LRU lists shared by all zswap pools. */ >> static struct list_lru zswap_list_lru; >> >> @@ -183,6 +190,7 @@ static struct shrinker *zswap_shrinker; >> * handle - zsmalloc allocation handle that stores the compressed page data >> * objcg - the obj_cgroup that the compressed memory is charged to >> * lru - handle to the pool's lru used to evict pages. >> + * store_time - Time when the entry was stored, for proactive writeback. >> */ >> struct zswap_entry { >> swp_entry_t swpentry; >> @@ -192,6 +200,7 @@ struct zswap_entry { >> unsigned long handle; >> struct obj_cgroup *objcg; >> struct list_head lru; >> + ktime_t store_time; > > On the implementation side - will this blow up struct zswap_entry > memory footprint? If so, can you guard this behind a CONFIG option, if > we are to go this route? Thanks for the review. I'll address this in v2. Thanks, Hao