From patchwork Tue Sep 24 15:30:22 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oleksandr Tyshchenko X-Patchwork-Id: 11159133 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id AE8DF13B1 for ; Tue, 24 Sep 2019 15:32:58 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7D0CD207FD for ; Tue, 24 Sep 2019 15:32:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="dN7PTuPE" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7D0CD207FD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1iCmmR-0007rW-Cu; Tue, 24 Sep 2019 15:31:07 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1iCmmP-0007r4-W3 for xen-devel@lists.xenproject.org; Tue, 24 Sep 2019 15:31:06 +0000 X-Inumbo-ID: 4af7dce0-dee0-11e9-bf31-bc764e2007e4 Received: from mail-lj1-x244.google.com (unknown [2a00:1450:4864:20::244]) by localhost (Halon) with ESMTPS id 4af7dce0-dee0-11e9-bf31-bc764e2007e4; Tue, 24 Sep 2019 15:30:53 +0000 (UTC) Received: by mail-lj1-x244.google.com with SMTP id y23so2348234lje.9 for ; Tue, 24 Sep 2019 08:30:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=sQRBacY7IWJeeQXPRyg+OlUCm3S/btufzJlQQaOIwrY=; b=dN7PTuPEfZu/swbJ4BENv+xHvySzwTp57pMW5yXhIP/EBvompkuSw0Xi1pOlNd25nb VhXsrJluOg/OOPlEkcvtVf8k74XXeWOMbAeV8bZLNu9ZI5oCF1iokNr5zHDMZhuK7IJ9 CNfINWtFCYLF4vpwr0TKaVYZ60gUZshIMt1aRD7UMV/imydgHdPv11gPXAlhPk2EWRX6 YXYcqem83i6YY/faCp9JM2vIHHQKFMW4G4nMiZ9dOF3ZV2BQkaBbyVf7WVktNX3l/gGk rNR4OPv4lWZVtnc6hx3Ur9uyaSFtDC2uZc9UU1Pbe7/mne2G2nBEMi/RxdPav0oG+po2 fuNw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=sQRBacY7IWJeeQXPRyg+OlUCm3S/btufzJlQQaOIwrY=; b=QB9odalJUBNlM1KgTkxHPeRpgYJXqImaT57qKiknjwN/eqpv5FxrAu4OTyUeCuj5UW PgkP39PnsV1sice3gNdIASPT94UNLKevyGtLHSPjQJW4sZRlAw/o++biooA1P31/WlfY Ugji4GnxWKwGWT642hJF8m4DNq/fid9425+cxOPmdPGMeS6quQGmDVVY7mCoHVZERsxt Mx2VGKUpNUu0XQwSDFfa0TYbRPdpLM/gJz8Jx7kWrLjjZqZMzqxvYP+W2fOgq7eVc67B n6NIHlub5gua6EfIG0JslVXuATWZk3pe3naKmTPqT0kb08Ywh8S9iu6G69Cu7e6FX3pi zVzw== X-Gm-Message-State: APjAAAXQZpgpE3Jl4wfXhW8HyOR3tAdE99yFO7ceNPh68RF6a6E6mpuW JEou+7Xx4xLMxM+fCF1J3bhQOQAbbWE= X-Google-Smtp-Source: APXvYqyNenFd6tU2ijaWmAxnjP/Z4c+kge27jfzseo4ya1NikrUCP9JxciXWb2r6vJM50l8bBXFlKg== X-Received: by 2002:a2e:654a:: with SMTP id z71mr2458830ljb.37.1569339051795; Tue, 24 Sep 2019 08:30:51 -0700 (PDT) Received: from otyshchenko.kyiv.epam.com (ll-74.141.223.85.sovam.net.ua. [85.223.141.74]) by smtp.gmail.com with ESMTPSA id z128sm525818lfa.1.2019.09.24.08.30.50 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 24 Sep 2019 08:30:51 -0700 (PDT) From: Oleksandr Tyshchenko To: xen-devel@lists.xenproject.org Date: Tue, 24 Sep 2019 18:30:22 +0300 Message-Id: <1569339027-19484-4-git-send-email-olekstysh@gmail.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1569339027-19484-1-git-send-email-olekstysh@gmail.com> References: <1569339027-19484-1-git-send-email-olekstysh@gmail.com> Subject: [Xen-devel] [PATCH V5 3/8] xen/common: Introduce _xrealloc function X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: sstabellini@kernel.org, Wei Liu , Konrad Rzeszutek Wilk , George Dunlap , Andrew Cooper , Ian Jackson , Tim Deegan , Oleksandr Tyshchenko , julien.grall@arm.com, Paul Durrant , Jan Beulich , volodymyr_babchuk@epam.com MIME-Version: 1.0 Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" From: Oleksandr Tyshchenko This patch introduces type-unsafe function which besides re-allocation handles the following corner cases: 1. if requested size is zero, it will behave like xfree 2. if incoming pointer is not valid (NULL or ZERO_BLOCK_PTR), it will behave like xmalloc If both pointer and size are valid the function will re-allocate and copy only if requested size and alignment don't fit in already allocated space. Subsequent patch will add type-safe helper macros. Signed-off-by: Oleksandr Tyshchenko CC: Andrew Cooper CC: George Dunlap CC: Ian Jackson CC: Jan Beulich CC: Julien Grall CC: Konrad Rzeszutek Wilk CC: Stefano Stabellini CC: Tim Deegan CC: Wei Liu CC: Paul Durrant --- Changes V4 -> V5: - avoid possible truncation with allocations of 4GiB or above - introduce helper functions add(strip)_padding to avoid duplicating the code - omit the unnecessary casts, change u32 to uint32_t when moving the code - use _xzalloc instead of _xmalloc to get the tail portion zeroed - update pointer according to the requsted alignment - compared against "size" instead of "tmp_size" for the allocations above PAGE_SIZE Changes V3 -> V4: - add check for the alignment compatibility - properly detect current size (take into the account a possible fake alignment header) - update comment in code/patch description Changes RFC -> V3: - behave like xmalloc if incoming pointer is ZERO_BLOCK_PTR or NULL - return ZERO_BLOCK_PTR after xfree if requested size is zero - add patch description - use allocator internals to recognize current size of the incoming pointer - do not re-allocate and copy if requested size fits in already allocated space ... Original patch was initially posted by Sameer Goel: https://lists.xen.org/archives/html/xen-devel/2017-06/msg00858.html This could be considered as another attempt to add it: https://www.mail-archive.com/kexec@lists.infradead.org/msg21335.html [As it was previously discussed with Julien in IRC] The reason for this patch to be an RFC is that patch itself is not completely correct and I don't fully understand what/how should be done for this patch to be accepted. Or whether community even wants this to go in. So, to avoid bike shedding, the first target is to collect feedback. For everyone who wants more details why this is needed and where used, please see next patch of this thread: "iommu/arm: Add lightweight iommu_fwspec support" In a nutshell, the upcoming "iommu_fwspec" support on ARM is going to use xrealloc to expand an array for device IDs. We really want to have "iommu_fwspec" support which will give us a generic abstract way to add new device to the IOMMU based on the generic IOMMU DT binding. --- xen/common/xmalloc_tlsf.c | 113 ++++++++++++++++++++++++++++++++++++++-------- xen/include/xen/xmalloc.h | 1 + 2 files changed, 96 insertions(+), 18 deletions(-) diff --git a/xen/common/xmalloc_tlsf.c b/xen/common/xmalloc_tlsf.c index e98ad65..a797019 100644 --- a/xen/common/xmalloc_tlsf.c +++ b/xen/common/xmalloc_tlsf.c @@ -554,10 +554,40 @@ static void tlsf_init(void) #define ZERO_BLOCK_PTR ((void *)-1L) #endif +static void *strip_padding(void *p) +{ + struct bhdr *b = p - BHDR_OVERHEAD; + + if ( b->size & FREE_BLOCK ) + { + p -= b->size & ~FREE_BLOCK; + b = p - BHDR_OVERHEAD; + ASSERT(!(b->size & FREE_BLOCK)); + } + + return p; +} + +static void *add_padding(void *p, unsigned long align) +{ + uint32_t pad; + + if ( (pad = -(long)p & (align - 1)) != 0 ) + { + void *q = p + pad; + struct bhdr *b = q - BHDR_OVERHEAD; + + ASSERT(q > p); + b->size = pad | FREE_BLOCK; + p = q; + } + + return p; +} + void *_xmalloc(unsigned long size, unsigned long align) { void *p = NULL; - u32 pad; ASSERT(!in_irq()); @@ -578,14 +608,7 @@ void *_xmalloc(unsigned long size, unsigned long align) return xmalloc_whole_pages(size - align + MEM_ALIGN, align); /* Add alignment padding. */ - if ( (pad = -(long)p & (align - 1)) != 0 ) - { - char *q = (char *)p + pad; - struct bhdr *b = (struct bhdr *)(q - BHDR_OVERHEAD); - ASSERT(q > (char *)p); - b->size = pad | FREE_BLOCK; - p = q; - } + p = add_padding(p, align); ASSERT(((unsigned long)p & (align - 1)) == 0); return p; @@ -598,10 +621,70 @@ void *_xzalloc(unsigned long size, unsigned long align) return p ? memset(p, 0, size) : p; } -void xfree(void *p) +void *_xrealloc(void *ptr, unsigned long size, unsigned long align) { - struct bhdr *b; + unsigned long curr_size, tmp_size; + void *p; + + if ( !size ) + { + xfree(ptr); + return ZERO_BLOCK_PTR; + } + if ( ptr == NULL || ptr == ZERO_BLOCK_PTR ) + return _xmalloc(size, align); + + ASSERT((align & (align - 1)) == 0); + if ( align < MEM_ALIGN ) + align = MEM_ALIGN; + + tmp_size = size + align - MEM_ALIGN; + + if ( tmp_size < PAGE_SIZE ) + tmp_size = (tmp_size < MIN_BLOCK_SIZE) ? MIN_BLOCK_SIZE : + ROUNDUP_SIZE(tmp_size); + + if ( !((unsigned long)ptr & (PAGE_SIZE - 1)) ) + { + curr_size = (unsigned long)PFN_ORDER(virt_to_page(ptr)) << PAGE_SHIFT; + + if ( size <= curr_size && ((unsigned long)ptr & (align - 1)) == 0 ) + return ptr; + } + else + { + struct bhdr *b; + + /* Strip alignment padding. */ + p = strip_padding(ptr); + + b = p - BHDR_OVERHEAD; + curr_size = b->size & BLOCK_SIZE_MASK; + + if ( tmp_size <= curr_size ) + { + /* Add alignment padding. */ + p = add_padding(p, align); + + ASSERT(((unsigned long)p & (align - 1)) == 0); + + return p; + } + } + + p = _xzalloc(size, align); + if ( p ) + { + memcpy(p, ptr, min(curr_size, size)); + xfree(ptr); + } + + return p; +} + +void xfree(void *p) +{ if ( p == NULL || p == ZERO_BLOCK_PTR ) return; @@ -626,13 +709,7 @@ void xfree(void *p) } /* Strip alignment padding. */ - b = (struct bhdr *)((char *)p - BHDR_OVERHEAD); - if ( b->size & FREE_BLOCK ) - { - p = (char *)p - (b->size & ~FREE_BLOCK); - b = (struct bhdr *)((char *)p - BHDR_OVERHEAD); - ASSERT(!(b->size & FREE_BLOCK)); - } + p = strip_padding(p); xmem_pool_free(p, xenpool); } diff --git a/xen/include/xen/xmalloc.h b/xen/include/xen/xmalloc.h index f075d2d..831152f 100644 --- a/xen/include/xen/xmalloc.h +++ b/xen/include/xen/xmalloc.h @@ -51,6 +51,7 @@ extern void xfree(void *); /* Underlying functions */ extern void *_xmalloc(unsigned long size, unsigned long align); extern void *_xzalloc(unsigned long size, unsigned long align); +extern void *_xrealloc(void *ptr, unsigned long size, unsigned long align); static inline void *_xmalloc_array( unsigned long size, unsigned long align, unsigned long num)