From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DF0A9265CA2 for ; Fri, 17 Jul 2026 10:18:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784283490; cv=none; b=Xtxy61iG2k0FJIdz71mPKI9waea85WxDZX+FVKaiGcwg+zG7YEh1yTvPdsAdNtC81txKIgzQDbFGShIVBhfJXiDUMcUAjCH8XRQZ2GtNiT96P0Rgh8oWFX1LaW/i60gIJmjjN3ye00EFtazHDEiYk2R08D7uzvHdhbG9KyDJiDI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784283490; c=relaxed/simple; bh=cBLpcuKVBuXnqpf8RSTi7j6d8+aJD8SFAcxZesNpDiQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=XCLvcdlJb4Vhe6NxRvFdcDVjMQz6tvfA2CQpf4GfxC9nb5Gnpv1bvo+E/jFfdqMjti0eWIBY7snt+7JiEsi6MzEPjW2rnNSWlpWPOP5fgGSGIV3vJ8Plr+HyX3LK1q5yYqtmofSMf3nDWa8Pm+MmNZ7cW6yaMp5U71tdx0ccIzc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Tr6zjCHk; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Tr6zjCHk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A202A1F000E9; Fri, 17 Jul 2026 10:18:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784283489; bh=AWew5gAcDsf0j+jxvhTHKUFsB6sy2+G105HgRYF0e18=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=Tr6zjCHkQoRcv1Eje8UKaES1+gOO+rO2bx2B9sKF/qi/FbWGimpnORT3niXxzA1fX cE0dgYDaunzXzLIMwA6l4c6JnvQcXno3L9jCw27E989INEI9kr9UzrG3rh334Drp74 jDoSLG7ciZQH9VNLyVUrk1O9J434culGQM+PB+k0NmPP/C9L0LnUl06kTYftYTzmrX gBjneyRl54gvDWUOoS1Od1PrmFUxTDGVwLlkBnHrbQ9369H4Sm26LeKdodnlI/HehT rAL84fbaM4SbuTmyyYYII5ftW2ai8tppqaIHbPJ9oWmAR8OyGfbDZf+DPidLZe/xXR zndKhK1fU0ljA== Message-ID: <85cb7ea8-8116-4092-8310-69b61eb8602c@kernel.org> Date: Fri, 17 Jul 2026 11:18:03 +0100 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 v6 0/5] Only free healthy pages in high-order has_hwpoisoned folio To: Jiaqi Yan , linmiaohe@huawei.com, ljs@kernel.org, ziy@nvidia.com, vbabka@kernel.org Cc: osalvador@kernel.org, harry.yoo@oracle.com, willy@infradead.org, osalvador@suse.de, jackmanb@google.com, hannes@cmpxchg.org, nao.horiguchi@gmail.com, william.roche@oracle.com, tony.luck@intel.com, wangkefeng.wang@huawei.com, jane.chu@oracle.com, akpm@linux-foundation.org, muchun.song@linux.dev, liam@infradead.org, rientjes@google.com, duenwen@google.com, jthoughton@google.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, vbabka@suse.cz, rppt@kernel.org, shuah@kernel.org, surenb@google.com, mhocko@suse.com, boudewijn@delta-utec.com References: <20260705180714.3708947-1-jiaqiyan@google.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 7/5/26 20:07, Jiaqi Yan wrote: > At the end of dissolve_free_hugetlb_folio(), a free HugeTLB > folio becomes non-HugeTLB and is released to buddy allocator > as a high-order folio, e.g. a folio that contains 262144 pages > if the folio was a 1G HugeTLB hugepage. > > This is problematic if the HugeTLB hugepage contained HWPoison > subpages. In that case, since buddy allocator does not check > HWPoison for non-zero-order folio, the raw HWPoison page can > be given out with its buddy page and be re-used by either > kernel or userspace. I still don't like the complexity of this, in particular, as we have different mechanisms in the page allocator already to try handling this, We also do have cases where we set the hwpoison bit, while a page is just about to get allocated from the buddy. So before we take it off the buddy, we might just hand out the page. check_new_pages() seems to check for PageHWPoison() and make us not hand out such pages. It's guarded by "check_pages" but it seems to do exactly what we are looking for, now? -- Cheers, David