From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wg0-f45.google.com (mail-wg0-f45.google.com [74.125.82.45]) by kanga.kvack.org (Postfix) with ESMTP id 32BEC6B0035 for ; Mon, 15 Sep 2014 07:33:50 -0400 (EDT) Received: by mail-wg0-f45.google.com with SMTP id z12so3804201wgg.16 for ; Mon, 15 Sep 2014 04:33:48 -0700 (PDT) Received: from pandora.arm.linux.org.uk (pandora.arm.linux.org.uk. [2001:4d48:ad52:3201:214:fdff:fe10:1be6]) by mx.google.com with ESMTPS id jz3si18443759wjc.2.2014.09.15.04.33.42 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Mon, 15 Sep 2014 04:33:42 -0700 (PDT) Date: Mon, 15 Sep 2014 12:33:25 +0100 From: Russell King - ARM Linux Subject: Re: [RFC v2] arm:extend the reserved mrmory for initrd to be page aligned Message-ID: <20140915113325.GD12361@n2100.arm.linux.org.uk> References: <35FD53F367049845BC99AC72306C23D103D6DB491609@CNBJMBX05.corpusers.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <35FD53F367049845BC99AC72306C23D103D6DB491609@CNBJMBX05.corpusers.net> Sender: owner-linux-mm@kvack.org List-ID: To: "Wang, Yalin" Cc: 'Will Deacon' , "'linux-kernel@vger.kernel.org'" , "'linux-arm-kernel@lists.infradead.org'" , "'linux-mm@kvack.org'" , "'linux-arm-msm@vger.kernel.org'" On Mon, Sep 15, 2014 at 07:07:20PM +0800, Wang, Yalin wrote: > this patch extend the start and end address of initrd to be page aligned, > so that we can free all memory including the un-page aligned head or tail > page of initrd, if the start or end address of initrd are not page > aligned, the page can't be freed by free_initrd_mem() function. Better, but I think it's more complicated than it needs to be: > Signed-off-by: Yalin Wang > --- > arch/arm/mm/init.c | 19 +++++++++++++++++-- > arch/arm64/mm/init.c | 37 +++++++++++++++++++++++++++++++++---- > 2 files changed, 50 insertions(+), 6 deletions(-) > > diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c > index 659c75d..8490b70 100644 > --- a/arch/arm/mm/init.c > +++ b/arch/arm/mm/init.c > @@ -277,6 +277,8 @@ phys_addr_t __init arm_memblock_steal(phys_addr_t size, phys_addr_t align) > void __init arm_memblock_init(const struct machine_desc *mdesc) > { > /* Register the kernel text, kernel data and initrd with memblock. */ > + phys_addr_t phys_initrd_start_orig __maybe_unused; > + phys_addr_t phys_initrd_size_orig __maybe_unused; > #ifdef CONFIG_XIP_KERNEL > memblock_reserve(__pa(_sdata), _end - _sdata); > #else > @@ -289,6 +291,13 @@ void __init arm_memblock_init(const struct machine_desc *mdesc) > phys_initrd_size = initrd_end - initrd_start; > } > initrd_start = initrd_end = 0; > + phys_initrd_start_orig = phys_initrd_start; > + phys_initrd_size_orig = phys_initrd_size; > + /* make sure the start and end address are page aligned */ > + phys_initrd_size = round_up(phys_initrd_start + phys_initrd_size, PAGE_SIZE); > + phys_initrd_start = round_down(phys_initrd_start, PAGE_SIZE); > + phys_initrd_size -= phys_initrd_start; > + > if (phys_initrd_size && > !memblock_is_region_memory(phys_initrd_start, phys_initrd_size)) { > pr_err("INITRD: 0x%08llx+0x%08lx is not a memory region - disabling initrd\n", > @@ -305,9 +314,10 @@ void __init arm_memblock_init(const struct machine_desc *mdesc) > memblock_reserve(phys_initrd_start, phys_initrd_size); > > /* Now convert initrd to virtual addresses */ > - initrd_start = __phys_to_virt(phys_initrd_start); > - initrd_end = initrd_start + phys_initrd_size; > + initrd_start = __phys_to_virt(phys_initrd_start_orig); > + initrd_end = initrd_start + phys_initrd_size_orig; > } > + I think all the above is entirely unnecessary. The memblock APIs (especially memblock_reserve()) will mark the overlapped pages as reserved - they round down the starting address, and round up the end address (calculated from start + size). Hence, this: > @@ -636,6 +646,11 @@ static int keep_initrd; > void free_initrd_mem(unsigned long start, unsigned long end) > { > if (!keep_initrd) { > + if (start == initrd_start) > + start = round_down(start, PAGE_SIZE); > + if (end == initrd_end) > + end = round_up(end, PAGE_SIZE); > + > poison_init_mem((void *)start, PAGE_ALIGN(end) - start); > free_reserved_area((void *)start, (void *)end, -1, "initrd"); > } is the only bit of code you likely need to achieve your goal. Thinking about this, I think that you are quite right to align these. The memory around the initrd is defined to be system memory, and we already free the pages around it, so it *is* wrong not to free the partial initrd pages. Good catch. -- FTTC broadband for 0.8mile line: currently at 9.5Mbps down 400kbps up according to speedtest.net. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org