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 177BD1ACEDE; Mon, 28 Sep 2026 03:38:19 +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=1790566701; cv=none; b=rjUx7RRiirFT6JiHvQMqdhV41qlj7jL3TRWEblX2JXf5rsfPa/tkF3DfxlZCD5CLLid7WizuSdG7ym8w8cQEOWLiVu6X1jrSI1LmWz4GlirAILluKl+hkEY1sp1R2w0PYHOrE3ULLzsTpPhIMv6982tZuFs9UkUW50TYMMU63+o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790566701; c=relaxed/simple; bh=e1FzCridveI351/gfFU1tms0yyFTfLVWqo9GWJ0c2g0=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=qL1ecP/xulKxKxdn2t8W9Vv+oCepUE5mCDcFpb/Ug65yfkIWeCOAjbG0S7GR5dN+VZiVmjmIPLY2TSdWpPvddjAl0OX5JLoXUEOw1vzC1zSGygqXX4fahemcqNhtIa6qwO8TStE5eXM+CLZGzdjdgEQTWpZuAGkIfTDi+U56kY0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=M8jfexNR; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="M8jfexNR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 388F51F000FF; Mon, 28 Sep 2026 03:38:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1790566699; bh=Rqd+kxmYgnmYy9//PxWDP0AuMpqwxlp40X1NB7XfM3U=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=M8jfexNRiMmn5SqJpBK6o3SBKOT0HgRRk9cgWxXQbDn6pmXiFaiW2OMkxLHbUwS5d AWY3tunpj+e3LTLNE6nOknZGSZu/zBOT4QQRUMfbIxV40WhmGPFoIfks2bG9gJwIco iAgzaVlcT+BSLLgdxPzrtPNJcORV+bgYVOmdu5jY= Date: Sun, 27 Sep 2026 20:38:18 -0700 From: Andrew Morton To: Martin Cracauer Cc: linux-mm@kvack.org, david@kernel.org, ljs@kernel.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, shuah@kernel.org, peterx@redhat.com, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH] selftests/mm: uffd-missing-wp: add GC related functionality test Message-Id: <20260927203818.2f4b34b37f4a6e1685c3d142@linux-foundation.org> In-Reply-To: References: X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) 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-Transfer-Encoding: 7bit On Sun, 27 Sep 2026 23:26:31 -0400 Martin Cracauer wrote: > Add a test that asserts that functionality needed for generational > garbage collection works. Namely to implement a write barrier using > userfaultfd instead of using segmentation faults. The planned target > is the GC in SBCL. > > The real GC will initially fill heap pages by using on-demand loading > of pages from an image file, either via mmap(2) or using userfaultfd > to decompress a page read from an image file made from individually > compressed blocks. This test doesn't do that so that it needs no disk > I/O and no decompression library. Instead, a fault will be filled by > copying page content from prepared pages in the heap. Thanks. Sashiko asked a couple of things: https://sashiko.dev/#/patchset/arneZ-KkRWUNI0Ho@cons.org