From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 BFC0D2F872; Tue, 21 Oct 2025 06:12:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761027175; cv=none; b=qpCq+oqFpOjvCe2ctebngCdh5QiePsmuTciD29xy1CK2gDeu5YLZ9ORbzDVluG/Hv4F7VyJ7yD8GViv2DPbKtkDf2N+hSDQDURt4MTM8q1TBZqIBeCrcMVhwbn2fu+S6hK1eLkKVdR3sDkc52gvnKNrA9MIZrIx45I4awn6HQ0I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761027175; c=relaxed/simple; bh=+QmnY748EjRGKjWLnl5sIMZrRRpbF0hAi5qW5DwTCqc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=KzDyKaNCWha+ZUJV+skjbCr/7BBCg7PhWrHxIVSz7NmBuorEY+DbzaM3r2cKqdYYwY7hDWuNJq67VI+OpvPHKM4gTSGzJ52Wj1Leb1xDrbyiqnHlJpNa6nZQzHhSbZBfDCjeB6n2m4GNbTbLl2Xz4yiXD1J1OQ+Qv0PWmoIBz/U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=ShKdqzOl; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="ShKdqzOl" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=32WXsKzxggeOILJADAf0lJ/XcojNDUkG87T7LB0uMmU=; b=ShKdqzOlsJZJ5PGyNK+WPgm08w YG05J6HLCcDbwjPvnI2QKbkgv/jKp9ozm4cWjoblrSDJhZ0TR5nkyWesExrjXvzpM5nGgaQuqd7V1 rvdQqa2snXe2hDLHng9fXY1sngvgapiVGUyprKX0IWXegzyi4+aXuZzyermYeCXnmCFdpp6bV3QWw jmh71KufOM6iT9U0CiMBHCGz2dLUYPXWZXk/5EZwARAimiB+s6wR5K0TATS6/PXzPHCVaGsqYJ1xL pgs4ZgTZum8hJdzxZYaGmGzcbeZaXKkXgzvEnVgYuB/0TWX9ayxP052nFyV78namlJzodSv305bya CnN0oLeg==; Received: from hch by bombadil.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1vB5bs-0000000FuQQ-39F3; Tue, 21 Oct 2025 06:12:40 +0000 Date: Mon, 20 Oct 2025 23:12:40 -0700 From: Christoph Hellwig To: Dave Chinner Cc: Kiryl Shutsemau , Andrew Morton , David Hildenbrand , Hugh Dickins , Matthew Wilcox , Alexander Viro , Christian Brauner , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Rik van Riel , Harry Yoo , Johannes Weiner , Shakeel Butt , Baolin Wang , "Darrick J. Wong" , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Kiryl Shutsemau Subject: Re: [RFC, PATCH 0/2] Large folios vs. SIGBUS semantics Message-ID: References: <20251020163054.1063646-1-kirill@shutemov.name> Precedence: bulk X-Mailing-List: linux-fsdevel@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: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Tue, Oct 21, 2025 at 10:28:02AM +1100, Dave Chinner wrote: > Fundamentally, we really don't care about the mapping/tlb > performance of the PTE fragments at EOF. Anyone using files large > enough to notice the TLB overhead improvements from mapping large > folios is not going to notice that the EOF mapping has a slightly > higher TLB miss overhead than everywhere else in the file. > > Please jsut fix the regression. Yeah. I'm not even sure why we're having this discussion. The behavior is mandated, we have test cases for it and there is literally no practical upside in changing the behavior from what we've done forever and what is mandated in Posix.