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Received: from loth.rohan.me.apana.org.au ([192.168.167.2]) by formenos.hmeau.com with smtp (Exim 4.96 #2 (Debian)) id 1vfA3D-00Fxah-2j; Mon, 12 Jan 2026 13:01:12 +0800 Received: by loth.rohan.me.apana.org.au (sSMTP sendmail emulation); Mon, 12 Jan 2026 13:01:11 +0800 Date: Mon, 12 Jan 2026 13:01:11 +0800 From: Herbert Xu To: Yosry Ahmed Cc: Sergey Senozhatsky , Andrew Morton , Nhat Pham , Minchan Kim , Johannes Weiner , Brian Geffon , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [RFC PATCH 2/2] zsmalloc: chain-length configuration should consider other metrics Message-ID: References: <9b7d6e6292c64f21b8d09def1b6723f02faffe88@linux.dev> <53zplsrqc66z4ea64cosy53zvttuuhgxr2ik7uw6i2zgluegyz@d3ulgntwnyw4> <2iophcy2e6vk72ypxeshmen66e7jhr52zr34parn4uw6vdyjef@frnpfrltrky2> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Stat-Signature: rqubok139pi536nbi5kdzyit3sbfsowa X-Rspamd-Queue-Id: BCC13C000D X-Rspam-User: X-Rspamd-Server: rspam02 X-HE-Tag: 1768194108-149289 X-HE-Meta: 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 LMTHtcPl yT9hXaWBQwv9nDkQZWc9710mkqo8RcNFiNT3RT5H0GpjCPLMQvuFRPNkMCQyZ1XhFxFfrFznb+j7vIvnSKntFVAp1YOfBgkoIFZcMAyVzjnNJomLMDd5KSBUjhQmGtHjdfkU3qdksJ2YEBystg6A5SikJ1XZl5jOYY2IZpMn5BQ6eDYRtA8nSzwBYR42gPxQaV+kLrs+g1SOtMEwQzoAgC+xcSvT2GRGX+c9kPhZwi5DpNMCOKQslk8A+OdZ9DcwFrvOn2XX9C3OhM5ohmfWy1Bq8RNNQou1B19Mc 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 Fri, Jan 09, 2026 at 04:02:51PM +0000, Yosry Ahmed wrote: > > Herbert, do you mind taking a look at this? It looks sane to me except > for one question below. Looks alright to me too. > > + size_t sizes[2]; > > + > > + /* this object spans two pages */ > > + sizes[0] = PAGE_SIZE - off; > > + sizes[1] = mem_len - sizes[0]; > > + > > + sg_init_table(sg, 2); > > + sg_set_page(sg, zpdesc_page(zpdesc), sizes[0], off); > > + > > + zpdesc = get_next_zpdesc(zpdesc); > > + sg = sg_next(sg); > > Is this stateful? Will the SG list be returned pointing at the second > page now? It makes no difference because we just called sg_init_table(sg, 2), so sg_next(sg) is equivalent to &sg[1]. Cheers, -- Email: Herbert Xu Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt