From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta0.migadu.com (out-105.mta0.migadu.com [91.218.175.105]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 76E403164BA for ; Mon, 21 Sep 2026 06:02:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.105 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789970568; cv=none; b=Mfiu6E2xlBrMXtIk5CGiA1hYzPo2ukn9JCv/2m2RIYsj0JcON/rde83dDjZCspoOYuQltTaj44Ai3+XQQB0NtXT3/3oAKea5dUuDMBvDCYbk2BlpVw6WWWu89vPKEXJ5KYr4+Od17Xu9YfQ+csyoCbLUz3yOj2dv69VCUJ4Wf+A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789970568; c=relaxed/simple; bh=PfaHpE1ReZ1v+qkpOG99rma3BnJ5b9o8YklSIsQbmDI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=pp9UPbbonVIKWgq4MPAmFL4fmUUe8nPfofb/tjI058pr3YGjiF7mAP2a3R1J3SpmkIJC7Nb+81GMeQNy3n66cmpOuE17EoyFEpSv1OIqwZ9KtzdEi9P2FJloNRkn+PqaE2zJDfugapuFFpNHGPbWZq9J12Fdv8xfntAMd8YLRnE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=EWhPzXWv; arc=none smtp.client-ip=91.218.175.105 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="EWhPzXWv" X-Envelope-To: linux-kernel@vger.kernel.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-kernel@vger.kernel.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 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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 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