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 299C5C0015E for ; Fri, 16 Jun 2023 16:48:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345560AbjFPQsQ (ORCPT ); Fri, 16 Jun 2023 12:48:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34998 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345620AbjFPQsN (ORCPT ); Fri, 16 Jun 2023 12:48:13 -0400 Received: from out-8.mta0.migadu.com (out-8.mta0.migadu.com [91.218.175.8]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E057130F9; Fri, 16 Jun 2023 09:48:10 -0700 (PDT) Date: Fri, 16 Jun 2023 12:48:02 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1686934088; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=IfKIglpY59qnffneasZzBrgWBI/BVVKcO3nvK+88q6Q=; b=f7uDVOP+LriTx1GPKpO/iGQAeI7fAgmRpvVnoi5jo3ti6yVsQ9wInwSxipV6MgfOy574mI FDCFPj1N9Nd5bgTFZS6HIo1mpnuNsg8Mx89vQT9KdcpGA0IcSmQVrnh8mL+CQCqd9x3abe jZmmh6fZtZim0+prcqCTRKU0uIKCYhg= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Kent Overstreet To: Mike Rapoport Cc: linux-kernel@vger.kernel.org, Andrew Morton , Catalin Marinas , Christophe Leroy , "David S. Miller" , Dinh Nguyen , Heiko Carstens , Helge Deller , Huacai Chen , Luis Chamberlain , Mark Rutland , Michael Ellerman , Nadav Amit , "Naveen N. Rao" , Palmer Dabbelt , Puranjay Mohan , Rick Edgecombe , Russell King , Song Liu , Steven Rostedt , Thomas Bogendoerfer , Thomas Gleixner , Will Deacon , bpf@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org, linux-mm@kvack.org, linux-modules@vger.kernel.org, linux-parisc@vger.kernel.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, loongarch@lists.linux.dev, netdev@vger.kernel.org, sparclinux@vger.kernel.org, x86@kernel.org Subject: Re: [PATCH v2 02/12] mm: introduce execmem_text_alloc() and jit_text_alloc() Message-ID: References: <20230616085038.4121892-1-rppt@kernel.org> <20230616085038.4121892-3-rppt@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230616085038.4121892-3-rppt@kernel.org> X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org On Fri, Jun 16, 2023 at 11:50:28AM +0300, Mike Rapoport wrote: > From: "Mike Rapoport (IBM)" > > module_alloc() is used everywhere as a mean to allocate memory for code. > > Beside being semantically wrong, this unnecessarily ties all subsystems > that need to allocate code, such as ftrace, kprobes and BPF to modules > and puts the burden of code allocation to the modules code. > > Several architectures override module_alloc() because of various > constraints where the executable memory can be located and this causes > additional obstacles for improvements of code allocation. > > Start splitting code allocation from modules by introducing > execmem_text_alloc(), execmem_free(), jit_text_alloc(), jit_free() APIs. > > Initially, execmem_text_alloc() and jit_text_alloc() are wrappers for > module_alloc() and execmem_free() and jit_free() are replacements of > module_memfree() to allow updating all call sites to use the new APIs. > > The intention semantics for new allocation APIs: > > * execmem_text_alloc() should be used to allocate memory that must reside > close to the kernel image, like loadable kernel modules and generated > code that is restricted by relative addressing. > > * jit_text_alloc() should be used to allocate memory for generated code > when there are no restrictions for the code placement. For > architectures that require that any code is within certain distance > from the kernel image, jit_text_alloc() will be essentially aliased to > execmem_text_alloc(). > > The names execmem_text_alloc() and jit_text_alloc() emphasize that the > allocated memory is for executable code, the allocations of the > associated data, like data sections of a module will use > execmem_data_alloc() interface that will be added later. I like the API split - at the risk of further bikeshedding, perhaps near_text_alloc() and far_text_alloc()? Would be more explicit. Reviewed-by: Kent Overstreet