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Received: from willy by casper.infradead.org with local (Exim 4.97.1 #2 (Red Hat Linux)) id 1rViIN-0000000HKmL-4244; Fri, 02 Feb 2024 01:24:44 +0000 Date: Fri, 2 Feb 2024 01:24:43 +0000 From: Matthew Wilcox To: Douglas Anderson Cc: Alexander Viro , Christian Brauner , Eric Biederman , Jan Kara , Kees Cook , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH] regset: use vmalloc() for regset_get_alloc() Message-ID: References: <20240201171159.1.Id9ad163b60d21c9e56c2d686b0cc9083a8ba7924@changeid> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240201171159.1.Id9ad163b60d21c9e56c2d686b0cc9083a8ba7924@changeid> X-Rspamd-Queue-Id: 95E4740009 X-Rspam-User: X-Stat-Signature: qgstsbgwfjqpi6bcswugubojp5jdezay X-Rspamd-Server: rspam03 X-HE-Tag: 1706837092-167671 X-HE-Meta: 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 2fA+xhnn P1OtzFSncSrtkXKukxqq552lst4ZrwJGTU+uIntidR1k8V7FdjgIuO/ywj+29VXvTLd5TsuoimJEUxflNeHMeGyP4J+cZ25EHEBVn2/zoVKi26bMq57n88gB8B49rBrpUK9CH1HkFEmpEtYHBf/hqFo1KvS7G1ZcXoZrt0Nfn3slze2kedWVcjH/jfA== 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 Thu, Feb 01, 2024 at 05:12:03PM -0800, Douglas Anderson wrote: > While browsing through ChromeOS crash reports, I found one with an > allocation failure that looked like this: > > chrome: page allocation failure: order:7, > mode:0x40dc0(GFP_KERNEL|__GFP_COMP|__GFP_ZERO), > nodemask=(null),cpuset=urgent,mems_allowed=0 That does seem bad ... > @@ -16,14 +17,14 @@ static int __regset_get(struct task_struct *target, > if (size > regset->n * regset->size) > size = regset->n * regset->size; > if (!p) { > - to_free = p = kzalloc(size, GFP_KERNEL); > + to_free = p = vmalloc(size); It's my impression that sometimes this size might be relatively small? Perhaps we should make this kvmalloc so that we can satisfy it from the slab allocator if it is small? Also, I assume that we don't rely on this memory being physically contiguous; we don't, for example, do I/O on it?