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From: Yosry Ahmed To: Vitaly Wool Cc: linux-mm@kvack.org, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, Nhat Pham , Shakeel Butt , Johannes Weiner , Igor Belousov , Minchan Kim , Sergey Senozhatsky Subject: Re: [PATCH v4] mm: add zblock allocator Message-ID: References: <20250412154207.2152667-1-vitaly.wool@konsulko.se> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250412154207.2152667-1-vitaly.wool@konsulko.se> X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Queue-Id: 6D6614000B X-Rspamd-Server: rspam04 X-Stat-Signature: 3gg9uxbzcy8asoaogb89ogb59ert5b8p X-HE-Tag: 1745318804-644792 X-HE-Meta: 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 w0NiTNkA /BPUj50awrg3haleGwEDC+OFMMi8ynBilr9jF0NwuTDNB5s7b2lOTcH17wuWeuzHwjeacOr0sxQbxJwYgAjBF1ukF3H3NUpfrzEraNvsKdQ4wOEb5ZjHy+d5LhDJGFb8VfIi9Ftx/cnsKuQ4DI+Nq5C4xx3f1q2v9u9vOoZUNH56xClZ5IYdH+IkXZg== 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 Sat, Apr 12, 2025 at 05:42:07PM +0200, Vitaly Wool wrote: > zblock is a special purpose allocator for storing compressed pages. > It stores integer number of same size objects per its block. These > blocks consist of several physical pages (2**n, i. e. 1/2/4/8). > > With zblock, it is possible to densely arrange objects of various sizes > resulting in low internal fragmentation. Also this allocator tries to > fill incomplete blocks instead of adding new ones, in many cases > providing a compression ratio comparable to zmalloc's. > > zblock is also in most cases superior to zsmalloc with regard to > average performance and worst execution times, thus allowing for better > response time and real-time characteristics of the whole system. > > High memory and page migration are currently not supported by zblock. > > Signed-off-by: Vitaly Wool > Signed-off-by: Igor Belousov Please CC me when sending zswap-related patches, not sure how you're picking the CC list. Also, CC'ing the zsmalloc maintainers here for the discussion of adding a new allocator vs improving zsmalloc. I didn't look too closely but I generally agree that we should improve zsmalloc where possible rather than add a new allocator. We are trying not to repeat the zbud/z3fold or slub/slob stories here. Zsmalloc is getting a lot of mileage from both zswap and zram, and is more-or-less battle-tested. Let's work toward building upon that instead of starting over.