From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A57D4E7545C for ; Tue, 3 Oct 2023 18:25:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231872AbjJCSZG (ORCPT ); Tue, 3 Oct 2023 14:25:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45326 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231667AbjJCSZF (ORCPT ); Tue, 3 Oct 2023 14:25:05 -0400 Received: from mail-io1-xd2a.google.com (mail-io1-xd2a.google.com [IPv6:2607:f8b0:4864:20::d2a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 48D3F90 for ; Tue, 3 Oct 2023 11:25:02 -0700 (PDT) Received: by mail-io1-xd2a.google.com with SMTP id ca18e2360f4ac-7748ca56133so12780339f.0 for ; Tue, 03 Oct 2023 11:25:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20230601.gappssmtp.com; s=20230601; t=1696357501; x=1696962301; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=9rzpEWrsqKqpDYBN8Dn6/31SDXQB3txD5dO6cAzCexM=; b=jQPZw6ALcJgq3tw85OcWMjyc2/okPmH/hebnRttS6ngaPdZ7TGbiANIZiLQ0S6t8/e 47kOVyUtPGC0B4GKC6zxj1IgCfbTaexuazW//F+He4iaF4ZvuKXYkMNyDTb9ZKYfi/Zb wOTWlsdqIosrjIplWQHyIXsRaCoU0rtt3ZCyVTdZhVnh36Tmks9w2/X3q1Usw+qK5Dul wkqx7fPdDGbRqSktVdmKu6uCqJsIko8Gg//YhaqFUInd3hdCI9N0ptNSmX01TMPTcAJD YRP+GyXthrVRsg0mvasMWBfoLy7A5W5FwurSqC7fCVwH6Sh+9Ws+ingvP7+Wuc598lb8 u2Dw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1696357501; x=1696962301; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=9rzpEWrsqKqpDYBN8Dn6/31SDXQB3txD5dO6cAzCexM=; b=OSmLoRI/vmAxWOSioqD/0LFdvd03Gzaup/alw4QA1XJScG8pdlShjuYMtWxcLtEW9Z Vr+Bly8prhVrq+f2lRVU69vo1B0h1cOlZBVJdxoFTQ1+ddZvUY/fMhVL9suADt0RhBSw yYE7qhlWlHwLPyb+NByGpMo8vUq6gvt/9d5OCKxht+UZdshi1WRgt9umHG90y6HvfVoO vPq9mQGQ+WhRnKoluCXxIvVzS82WnFb8X3HDRUxzFd+6YeoSw8vPfsctDJZsUHGusGEZ oQ5vBGgMMPEMGZoU0gef7iILXyB2rTZaeANOpXbXMnD+ziOADyl+yP5OL3aoQClQx/rq dnxQ== X-Gm-Message-State: AOJu0YxlF/1uCy2HcwfqQ2K1Bp8Cz50G4QedwCg0J+lscJgfoetQzhSu +Ek6dkC5olykFlh7xE4A8VVC0MESetA12aQZgBM= X-Google-Smtp-Source: AGHT+IFIzPUp2EoJzTqN0xAfit0Kv04oZuxAJs70f0uUJDG645VzHPHhD8ZoAEz5FEn7EMbjV+o7zg== X-Received: by 2002:a05:6602:3a05:b0:792:6be4:3dcb with SMTP id by5-20020a0566023a0500b007926be43dcbmr203242iob.2.1696357501627; Tue, 03 Oct 2023 11:25:01 -0700 (PDT) Received: from [192.168.1.94] ([96.43.243.2]) by smtp.gmail.com with ESMTPSA id fy5-20020a0566381e8500b0043d7ef4de07sm493024jab.5.2023.10.03.11.25.00 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 03 Oct 2023 11:25:01 -0700 (PDT) Message-ID: <581df26c-ff4b-4e27-ba06-b7fef966a6bd@kernel.dk> Date: Tue, 3 Oct 2023 12:25:00 -0600 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] io_uring: don't allow IORING_SETUP_NO_MMAP rings on highmem pages Content-Language: en-US To: Jeff Moyer Cc: io-uring References: <4c9eddf5-75d8-44cf-9365-a0dd3d0b4c05@kernel.dk> <08c0b5de-cf5e-432f-b8d6-a60204308d3a@kernel.dk> From: Jens Axboe In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 10/3/23 12:24 PM, Jeff Moyer wrote: > Jens Axboe writes: > >> On 10/3/23 10:30 AM, Jeff Moyer wrote: >>> Hi, Jens, >>> > [snip] >>> What do you think about throwing a printk_once in there that explains >>> the problem? I'm worried that this will fail somewhat randomly, and it >>> may not be apparent to the user why. We should also add documentation, >>> of course, and encourage developers to add fallbacks for this case. >> >> For both cases posted, it's rather more advanced use cases. And 32-bit >> isn't so prevalent anymore, thankfully. I was going to add to the man >> pages explaining this failure case. Not sure it's worth adding a printk >> for though. > > I try not to make decisions based on how prevalent I think a particular > configuration is (mainly because I'm usually wrong). Anyway, it's not a > big deal, I'm glad you gave it some thought. Me neither, but I think we can all safely agree that 32-bit highmem is thankfully not on the uptick :-) >> FWIW, once I got an arm32 vm setup, it fails everytime for me. Not sure >> how it'd do on 32-bit x86, similarly or more randomly. But yeah it's >> definitely at the mercy of how things are mapped. > > ...and potentially the load on the system. Anyway, it's fine with me to > keep it as is. We can always add a warning later if it ends up being a > problem. Certainly! -- Jens Axboe