From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B9466C982ED for ; Mon, 21 Sep 2026 06:02:49 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 93AE16B00D9; Mon, 21 Sep 2026 02:02:48 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 911AD6B00DB; Mon, 21 Sep 2026 02:02:48 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 84E686B00DD; Mon, 21 Sep 2026 02:02:48 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 5A9696B00D9 for ; Mon, 21 Sep 2026 02:02:48 -0400 (EDT) Received: from smtpin10.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 70D6BA63FF for ; Mon, 21 Sep 2026 06:02:47 +0000 (UTC) X-FDA: 85236725574.10.7FA609C Received: from mta0.migadu.com (out-106.mta0.migadu.com [91.218.175.106]) by imf02.hostedemail.com (Postfix) with ESMTP id 5CB458000A for ; Mon, 21 Sep 2026 06:02:45 +0000 (UTC) Authentication-Results: imf02.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=EWhPzXWv; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf02.hostedemail.com: domain of lance.yang@linux.dev designates 91.218.175.106 as permitted sender) smtp.mailfrom=lance.yang@linux.dev ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1789970565; b=4cCjCYfcSXWcbO2l7UvM+SuvkIBlYrGbZ750mJI1p2Jsu8/HZBENgZfvVAEBHYUzHy/v36 XFwx6A6FShWXpStNpLeuRQ7uUZrV5/DrU+QBmlNlDVJy5Ha7bbJYgzP4rM38X5hvV+/L6p 7oTnXRB+TGR77/NTcqEIcRmSon23xg8= ARC-Authentication-Results: i=1; imf02.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=EWhPzXWv; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf02.hostedemail.com: domain of lance.yang@linux.dev designates 91.218.175.106 as permitted sender) smtp.mailfrom=lance.yang@linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1789970565; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=IKorgmJZ/hNPXKbpIqBxQQxb0y5na8M7PnGaVplvaP0=; b=TQXHSFAsF4VJ5soNXwKCXdQtEBHubRybDecNvnlDqn/rAlYkiL++WkNWATSdc9KQPGFSsM 2vSWvg9ZxHl8kjWxIHUq3fgc0XTMDCuKJWJBC10fYEUboFt1gN2UsJwFyA9onpywc1enGJ X4CAk+8dHDQHvy2CQ7cRjK5H9OQprCc= X-Envelope-To: linux-mm@kvack.org DKIM-Signature: a=rsa-sha256; bh=PfaHpE1ReZ1v+qkpOG99rma3BnJ5b9o8YklSIsQbmDI=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1789970564; v=1; x=1790575364; b=EWhPzXWvUVnLorbPKvbRGme95f8+50nf2qubpgK5CbqYcyKGyE3YFPrmtKn0clGq2EMRImKM HXyIoNFmFrjnHzUJP44fa75CjaajYYxPX7Ep4hsxIV9Bs6cqgA0YVou2eeNgKqBfDhT/tJHPQXl eHEPZxWxLZYNp9tbjr2vKCcE= X-Envelope-To: linux-mm@kvack.org Received: by smtp.migadu.com with ESMTPS id 8c663889e002f29c; Mon, 21 Sep 2026 06:02:43 +0000 X-Mizu-Trace-ID: 8c663889e002f29c X-Migadu-Flow: FLOW_OUT Message-ID: <58fee197-7baa-4507-948e-13b58bc3c6fa@linux.dev> Date: Mon, 21 Sep 2026 14:02:27 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 01/17] mm/zsmalloc: replace PG_private with pointer comparison To: Zi Yan Cc: linux-mm@kvack.org, Muchun Song , Andrew Morton , Vlastimil Babka , Mike Rapoport , "Liam R. Howlett" , David Hildenbrand , Qi Zheng , Nico Pache , Usama Arif , Baolin Wang , "Matthew Wilcox (Oracle)" , Lorenzo Stoakes , Suren Baghdasaryan , Johannes Weiner , Dev Jain , Barry Song , Ryan Roberts , Alistair Popple , Shakeel Butt , Kairui Song , linux-kernel@vger.kernel.org, Minchan Kim , Sergey Senozhatsky , Gregory Price , Ying Huang , Michal Hocko References: <20260920-remove-pg_private-v5-0-bb68b6a21869@nvidia.com> <20260920-remove-pg_private-v5-1-bb68b6a21869@nvidia.com> Content-Language: en-US From: Lance Yang In-Reply-To: <20260920-remove-pg_private-v5-1-bb68b6a21869@nvidia.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 5CB458000A X-Stat-Signature: cj3g1q196d9wqqg98mjwpzcrbakkdtf7 X-HE-Tag: 1789970565-703818 X-HE-Meta: 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 SLI2yqRe 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2026/9/21 10:27, Zi Yan wrote: > zsmalloc uses PG_private to indicate first zpdesc in a zspage chain. It is > equivalent to check zpdesc == zspage->first_zpdesc. Replace > is_first_zpdesc() with zpdesc == zspage->first_zpdesc in obj_allocated(). > > For get_first_zpdesc(), first_zpdesc is from zspage->first_zpdesc, so > replace is_first_zpdesc() with first_zpdesc->zspage == zspage, the second > requirement of a zspage chain, where all zpdescs point to the same zspage. > > is_first_zpdesc(), is only used in VM_BUG_ON_PAGE(), so performance impact > should be negligible. While at it, change VM_BUG_ON() to > VM_WARN_ON_ONCE_PAGE(). > > It prepares for a future commit that remove PG_private. > > No functional change intended. > > Assisted-by: LLM > To: Minchan Kim > To: Sergey Senozhatsky > To: Andrew Morton > Cc: linux-mm@kvack.org > Cc: linux-kernel@vger.kernel.org > Acked-by: Johannes Weiner > Reviewed-by: Sergey Senozhatsky > Acked-by: David Hildenbrand (Arm) > Signed-off-by: Zi Yan > --- Nice work! Feel free to add: Reviewed-by: Lance Yang