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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9FDB8C5320E for ; Tue, 27 Aug 2024 06:49:40 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 346D66B007B; Tue, 27 Aug 2024 02:49:40 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2F61A6B0082; Tue, 27 Aug 2024 02:49:40 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1BE576B0083; Tue, 27 Aug 2024 02:49:40 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 01DE96B007B for ; Tue, 27 Aug 2024 02:49:39 -0400 (EDT) Received: from smtpin22.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 9B0D14166D for ; Tue, 27 Aug 2024 06:49:39 +0000 (UTC) X-FDA: 82497099678.22.6A8325B Received: from mail-ed1-f44.google.com (mail-ed1-f44.google.com [209.85.208.44]) by imf18.hostedemail.com (Postfix) with ESMTP id B6C331C0010 for ; Tue, 27 Aug 2024 06:49:37 +0000 (UTC) Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=suse.com header.s=google header.b=Gq7lL3J+; spf=pass (imf18.hostedemail.com: domain of mhocko@suse.com designates 209.85.208.44 as permitted sender) smtp.mailfrom=mhocko@suse.com; dmarc=pass (policy=quarantine) header.from=suse.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1724741335; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=DqtpVWY8T6ecoXnDsB9l8HlClxrmCb3D7K0NvHPEgqM=; b=Eyx8aJjCJREGKh39ZDLHK0PgkOc3lOF/AnGOoCEF5JNjRyw1VEHpPC0fIR+JEyad1ZkywZ 5ll4JDGqYhGKftNiw1UE5Bs3NHpsXJyGqDjVZ6tYcxXvd4RsGKwf7b02Pb79SpKdhyxpgF l5UbwECWiIfh/c0976ar7yiW26wYErs= ARC-Authentication-Results: i=1; imf18.hostedemail.com; dkim=pass header.d=suse.com header.s=google header.b=Gq7lL3J+; spf=pass (imf18.hostedemail.com: domain of mhocko@suse.com designates 209.85.208.44 as permitted sender) smtp.mailfrom=mhocko@suse.com; dmarc=pass (policy=quarantine) header.from=suse.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1724741335; a=rsa-sha256; cv=none; b=iGGca5AHk234cJblkRp5q/79ku/LwJRZuVWyuTYUEVgpNETM/R4ThAeOmr4WzoZOvaWC8T IEcfZ2h/ENj12keU9vMv9bTZtJhJ1KahNia8h3FW9JUU4yt7Gb9Iy2Q/lRYOG8Ptxg19j1 Ky9Olx+ym5IpEEqN+oK5WZvwUfEEK9g= Received: by mail-ed1-f44.google.com with SMTP id 4fb4d7f45d1cf-5c0abaae174so1963311a12.1 for ; Mon, 26 Aug 2024 23:49:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1724741376; x=1725346176; darn=kvack.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=DqtpVWY8T6ecoXnDsB9l8HlClxrmCb3D7K0NvHPEgqM=; b=Gq7lL3J+w9BwTJ1lH4ApQQwWzBeE9/CBaTsI3efZ25/Wc7iMN09vXeVetuBKQfjF7R lwQYH4gnmaY29ZzyVpi6emlOLi7VPBSUFi/f5iZaU/cxDO+FfJamxRtcZyKkLam0K2Rk U7cc02qtt8a2SFwHsxQ4+FaMraLrXoZAFzgAXCGkNOGxeFg8hnXsrD1d/2KS/vHMvkm1 I2MDIY8EfuiuIABBZp4XP6BFUlsd3sfc4foXrAEs7fratIFzdlZES05Uch1TaIygI71q JiPe/tKfz2WeC5yaqbdl473SVtnMKTpQdmzXRfYtNDwwkCbyEkPUb3d34ebDQekDmXrJ V+rA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1724741376; x=1725346176; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=DqtpVWY8T6ecoXnDsB9l8HlClxrmCb3D7K0NvHPEgqM=; b=ZVk/eztS0dVkxpo1GN7IXkkECP5AAhu8nhR8zjKT1s08BMh7mptEzN4gA56LpuXNDs L6zU7UCrbTo6N82sqg0fUoaKwy4fITCTR+WE84dPPKzjr6QVl9ebodRLIo4JiPthzaeL l5RTNtol8+yEvksu69tYslzcQUGwcsybpvkuV8Lm221EGH8GOZJOU401dZo0pOtDI9Nt xVn+wKLYQ/WH1ORL7WiPFq9GKeEf+i5uJE4rCoJ31iGDjDewOwqp0HbCq0IYJOUTJcOS AXDnB7/2G9LRoKv/4JBp2FYixxtZHtQ4krFTcRdRBeQ2oHYSPUxpffHcUuETrMX/iMVd Sikw== X-Forwarded-Encrypted: i=1; AJvYcCWA7lrzmM3z2xE0ZVdn7BV871IIcfWa5irahJv22sMaVeqJ9xem8Mggl8ZyF2N0jO5GY6cWfBGZYw==@kvack.org X-Gm-Message-State: AOJu0YyQ+0a6d/F6IACP7JARw8jipiWHZrfEazPRKB5+Om1yq1EbFtbm cN19TudOlhHKP/s/9UJkwk46Bf1Y3IvLom4GmywafooyWuaHJuwz24Lqw15G9T4= X-Google-Smtp-Source: AGHT+IEQaDxUQ/mlcLiBRdVgUBiBvE1qUZl0Y74jY/67JgEu7wmyQfM1VHkIQX+Tr0cFaJ7OOxTEPw== X-Received: by 2002:a17:907:6d0a:b0:a86:7c5d:1856 with SMTP id a640c23a62f3a-a86e3be5c89mr137351066b.46.1724741376203; Mon, 26 Aug 2024 23:49:36 -0700 (PDT) Received: from localhost (109-81-92-122.rct.o2.cz. [109.81.92.122]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-a86e582c41bsm69699366b.98.2024.08.26.23.49.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 26 Aug 2024 23:49:35 -0700 (PDT) Date: Tue, 27 Aug 2024 08:49:35 +0200 From: Michal Hocko To: Uladzislau Rezki Cc: Hailong Liu , Andrew Morton , Barry Song <21cnbao@gmail.com>, Christoph Hellwig , Vlastimil Babka , Tangquan Zheng , stable@vger.kernel.org, Baoquan He , Matthew Wilcox , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [RESEND PATCH v1] mm/vmalloc: fix page mapping if vm_area_alloc_pages() with high order fallback to order 0 Message-ID: References: <20240815220709.47f66f200fd0a072777cc348@linux-foundation.org> <20240816091232.fsliktqgza5o5x6t@oppo.com> <20240816114626.jmhqh5ducbk7qeur@oppo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam03 X-Rspam-User: X-Rspamd-Queue-Id: B6C331C0010 X-Stat-Signature: di15hho3ie4iw1gfuxt34ruq8655z1ua X-HE-Tag: 1724741377-923880 X-HE-Meta: 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 ubfFzrht 0R/5RpbO1isPLtcAYrqYhBT1dvH+rHyEhJtg11qpCvzfRjVCqwhgkO5Ie9idwmnb4Vd0Z2eRWCJ8y6tmJBhPEFFcLsTGyjQppIshYBvVs+Qp2IBswScDSYELjojD6VbWN2qeHElcLd7qlQnKLn3+U1cONibN20AFrVHJ0O7F68KPXefGmvG0RYBQy2kxK86RdFJKecNQvhRVRSELSaD4RJ1Vwl4e1JfevBRCj8evFZpHlFyP0cwF1wK3WY2hSQr0PHK1wzRMsm8ofDbx96IrqzOpLSj5eucjUx7XfhCwNBxdk3s/aRXGmgkrc10XG2FNFyLotyeRRG6c0SfoD5NWzE8AqTw== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon 26-08-24 14:38:40, Uladzislau Rezki wrote: > On Mon, Aug 26, 2024 at 09:52:42AM +0200, Michal Hocko wrote: > > On Fri 23-08-24 18:42:47, Uladzislau Rezki wrote: > > [...] > > > @@ -3666,7 +3655,16 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask, > > > set_vm_area_page_order(area, page_shift - PAGE_SHIFT); > > > page_order = vm_area_page_order(area); > > > > > > - area->nr_pages = vm_area_alloc_pages(gfp_mask | __GFP_NOWARN, > > > + /* > > > + * Higher order nofail allocations are really expensive and > > > + * potentially dangerous (pre-mature OOM, disruptive reclaim > > > + * and compaction etc. > > > + * > > > + * Please note, the __vmalloc_node_range_noprof() falls-back > > > + * to order-0 pages if high-order attempt has been unsuccessful. > > > + */ > > > + area->nr_pages = vm_area_alloc_pages(page_order ? > > > + gfp_mask &= ~__GFP_NOFAIL : gfp_mask | __GFP_NOWARN, > > > node, page_order, nr_small_pages, area->pages); > > > > > > atomic_long_add(area->nr_pages, &nr_vmalloc_pages); > > > > > > > > > Is that aligned with your wish? > > > > I am not a great fan of modifying gfp_mask inside the ternary operator > > like that. It makes the code harder to read. Is there any actual reason > > to simply drop GFP_NOFAIL unconditionally and rely do the NOFAIL > > handling for all orders at the same place? > > > 1. So, for bulk we have below: > > /* gfp_t bulk_gfp = gfp & ~__GFP_NOFAIL; */ > > I am not sure if we need it but it says it does not support it which > is not clear for me why we have to drop __GFP_NOFAIL for bulk(). There > is a fallback to a single page allocator. If passing __GFP_NOFAIL does > not trigger any warning or panic a system, then i do not follow why > we drop that flag. > > Is that odd? I suspect this was a pre-caution more than anything. > 2. High-order allocations. Do you think we should not care much about > it when __GFP_NOFAIL is set? Same here, there is a fallback for order-0 > if "high" fails, it is more likely NO_FAIL succeed for order-0. Thus > keeping NOFAIL for high-order sounds like not a good approach to me. We should avoid high order allocations with GFP_NOFAIL at all cost. > 3. "... at the same place?" > Do you mean in the __vmalloc_node_range_noprof()? > > __vmalloc_node_range_noprof() > -> __vmalloc_area_node(gfp_mask) > -> vm_area_alloc_pages() > > if, so it is not straight forward, i.e. there is one more allocation: > > > static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask, > pgprot_t prot, unsigned int page_shift, > int node) > { > ... > /* Please note that the recursion is strictly bounded. */ > if (array_size > PAGE_SIZE) { > area->pages = __vmalloc_node_noprof(array_size, 1, nested_gfp, node, > area->caller); > } else { > area->pages = kmalloc_node_noprof(array_size, nested_gfp, node); > } > ... > } > > > whereas it is easier to do it inside of the __vmalloc_area_node(). Right. The allocation path is quite convoluted here. If it is just too much of a hassle to implement NOFAIL at a single place then we should aim at reducing that. Having that at 3 different layers is just begging for inconsistences. -- Michal Hocko SUSE Labs