From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta1.migadu.com (out-86.mta1.migadu.com [95.215.58.86]) (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 823DB432309 for ; Mon, 17 Aug 2026 16:05:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.86 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786982741; cv=none; b=L/amRmbwPJmU900+cGPwQpotVgdaF48uRev4L+umhJa5gnJA5y3dDqvZeW11HkpzkMSAQ4ftPxne94Gf7cEt4XWSI+4vDFPgkG5L3aSqD59qsqWWulfQ/gS5b7gD2Aj4qtWIDxVrBouCAxsWCvtth0r2WSgYE94gKoZvrLxiwGI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786982741; c=relaxed/simple; bh=1HL8LPVk8C1Xphfp1mnmMSDi25dP9z8IxQZoB/0vnw4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=skBf8/JxNxanZt4E7xetsJ8UFqeAXwOag9FyFlBWbe6XNBfjmmYcNzq1lWk+iGeARdrG5xJlc0eJvGODvF9CzLdRbDr1CplNaiDY+4DN5nQLDpNUbHRjKeDU0s4Sg/fJL2k3VVBA3F964/iJS5tNVCB5hSXUj/K2spj8kLAlWV4= 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=vZGmMbem; arc=none smtp.client-ip=95.215.58.86 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="vZGmMbem" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=1HL8LPVk8C1Xphfp1mnmMSDi25dP9z8IxQZoB/0vnw4=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1786982737; v=1; x=1787587537; b=vZGmMbemxlpB/sWbwVXFSfd1oZ8m53L7el3swG4MzBOEUdhZP1XwebRqQ5e8JZyd2K9UvBRe Xh+rso3iyRyV9zXXwbP9Ys57pXZHtpwbybV3VfqRNOeK/53bcKWUrpbi0qpw13JKIEwf7aBrjG5 0qRMtDw5GSI9QjS3DSFmnOwc= X-Envelope-To: linux-kernel@vger.kernel.org Received: from localhost (2a03:2880:10ff:4::) by smtp.migadu.com with ESMTPS id 88455a43fb1c0c1e; Mon, 17 Aug 2026 16:05:37 +0000 X-Migadu-Flow: FLOW_OUT Date: Mon, 17 Aug 2026 09:05:35 -0700 From: Shakeel Butt To: Qi Zheng Cc: hughd@google.com, baolin.wang@linux.alibaba.com, usama.arif@linux.dev, brauner@kernel.org, akpm@linux-foundation.org, david@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Qi Zheng Subject: Re: [PATCH v4 2/4] mm: memcontrol: make obj_cgroup_memcg() handle NULL objcg Message-ID: References: <09bcf74312246a6e4146be8a0cb9787f8beddb28.1786955972.git.zhengqi.arch@bytedance.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <09bcf74312246a6e4146be8a0cb9787f8beddb28.1786955972.git.zhengqi.arch@bytedance.com> On Mon, Aug 17, 2026 at 05:03:26PM +0800, Qi Zheng wrote: > From: Qi Zheng > > obj_cgroup_memcg() currently requires a non-NULL objcg, so callers that > may hold a NULL objcg must guard the call with an explicit NULL check. > This pattern is duplicated in folio_memcg(), folio_memcg_check(), > mm/page_owner.c, and mm/zswap.c. > > Teach obj_cgroup_memcg() to accept NULL and return NULL in that case, then > remove the redundant NULL checks at the call sites. Also remove the > mem_cgroup_from_entry() wrapper in zswap, which existed solely to provide > this NULL-safe behaviour, and replace its two callers with direct > obj_cgroup_memcg() calls. > > No functional change intended. > > Signed-off-by: Qi Zheng Acked-by: Shakeel Butt