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Wed, 14 Aug 2024 20:13:20 -0700 (PDT) Received: from google.com ([2401:fa00:8f:203:f7dc:2307:3c4b:963e]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-201f03a565bsm3116565ad.263.2024.08.14.20.13.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 14 Aug 2024 20:13:20 -0700 (PDT) Date: Thu, 15 Aug 2024 12:13:14 +0900 From: Sergey Senozhatsky To: Alex Shi Cc: Matthew Wilcox , Sergey Senozhatsky , Yosry Ahmed , Andrew Morton , alexs@kernel.org, Vitaly Wool , Miaohe Lin , linux-kernel@vger.kernel.org, linux-mm@kvack.org, minchan@kernel.org, david@redhat.com, 42.hyeyoo@gmail.com, nphamcs@gmail.com Subject: Re: [PATCH v5 00/21] mm/zsmalloc: add zpdesc memory descriptor for zswap.zpool Message-ID: <20240815031314.GA12106@google.com> References: <20240806022143.3924396-1-alexs@kernel.org> <20240806022311.3924442-1-alexs@kernel.org> <20240806123213.2a747a8321bdf452b3307fa9@linux-foundation.org> <20240807051754.GA428000@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 15CC312000E X-Stat-Signature: yyi5crm94oikd7as4g11nxiieuy6hn78 X-Rspam-User: X-HE-Tag: 1723691601-451151 X-HE-Meta: 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 eOQ3zFW4 G1IALrZGyCSTA4HbxDCJ9Gc6eiH3YodXeSf5E4V1EWDUuCoWhusCzEyuJRYRq1HfE8EzlI1nbpQcW8RlxZdVUNsG34TuhJgaRPAId+Lf0R0ko00h2f3+TFu5tYm5F9WZjaz9Y/VSMqnbrDjXNn2yIOe+RzheuJWh0Ts/3kb2PN31huHg3G8XDUwYFeOEKiDS2DNHPI87Um1sj9KMEJk0glqIIItm230BOuhbA5H4nf19YOWNWRNy4wX9SBX5lbjUAlWFM9b8A6+ihypjbOIDGU0wq6ASPTnicMOOwVzs1ucS3AxOnOe+fyz+BhYJ09Drk22KOvL6+i0PcaSJcS+srcfLgN1XTwZAVS2cVwWuYWkNI20l5KRSpjmdlQVIRwyU/fl9fZkfVW70/zalqZjhf6hunOQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On (24/08/09 10:32), Alex Shi wrote: [..] > >> and we "chain" zpdesc-s to form a zspage, and make each of them point to > >> a corresponding struct page (memdesc -> *page), then it'll resemble current > >> zsmalloc and should work for everyone? I also assume for zspdesc-s zsmalloc > >> will need to maintain a dedicated kmem_cache? > > Right, we could do that. Each memdesc has to be a multiple of 16 bytes, > > sp we'd be doing something like allocating 32 bytes for each page. > > Is there really 32 bytes of information that we want to store for > > each page? Or could we store all of the information in (a somewhat > > larger) zspage? Assuming we allocate 3 pages per zspage, if we allocate > > an extra 64 bytes in the zspage, we've saved 32 bytes per zspage. > > Thanks for the suggestions! Yes, it's a good direction we could try after this > patchset. Alex, may I ask what exactly you will "try"?