From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760586Ab0I1CoE (ORCPT ); Mon, 27 Sep 2010 22:44:04 -0400 Received: from rcsinet10.oracle.com ([148.87.113.121]:18000 "EHLO rcsinet10.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759826Ab0I1CoC (ORCPT ); Mon, 27 Sep 2010 22:44:02 -0400 Message-ID: <4CA155F2.5030101@kernel.org> Date: Mon, 27 Sep 2010 19:41:54 -0700 From: Yinghai Lu User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.11) Gecko/20100714 SUSE/3.0.6 Thunderbird/3.0.6 MIME-Version: 1.0 To: Vivek Goyal CC: "H. Peter Anvin" , Ingo Molnar , kexec , caiqian@redhat.com, linux-kernel@vger.kernel.org Subject: Re: kexec load failure introduced by "x86, memblock: Replace e820_/_early string with memblock_" References: <632974489.2046131285586512527.JavaMail.root@zmail06.collab.prod.int.phx2.redhat.com> <4CA11918.7050708@kernel.org> <4CA11FB7.2080101@zytor.com> <4CA126BE.7000609@kernel.org> <4CA1283C.9010105@zytor.com> <4CA12976.5060504@kernel.org> <4CA129EB.5000309@zytor.com> <4CA12BAB.1040308@kernel.org> <20100928005358.GA6456@redhat.com> In-Reply-To: <20100928005358.GA6456@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/27/2010 05:53 PM, Vivek Goyal wrote: > Actually, hardcoding the upper limit to 4G is probably not the best idea. > Kexec loads the the relocatable binary (purgatory) and I remember that > one of the generated relocation type was signed 32 bit and allowed max value > to be 2G only. So IIRC, purgatory code always needed to be loaded below 2G. also kexec want bzImage under 37ffffff. > > I liked HPA's other idea better of introducing memblock_find_in_range_lowest() > so that we search bottom up and not rely on a specific upper limit. > Please check. [PATCH -v4] x86, memblock: Fix crashkernel allocation Cai Qian found crashkernel is broken with x86 memblock changes 1. crashkernel=128M@32M always reported that range is used, even first kernel is small no one use that range 2. always get following report when using "kexec -p" Could not find a free area of memory of a000 bytes... locate_hole failed The root cause is that generic memblock_find_in_range() will try to get range from top_down. But crashkernel do need from low and specified range. Let's limit the target range with rash_base + crash_size to make sure that We get range from bottom. -v4: add find_memblock_find_in_range_lowest() according to hpa and vivik. Reported-and-Bisected-by: CAI Qian Signed-off-by: Yinghai Lu --- arch/x86/include/asm/memblock.h | 2 + arch/x86/kernel/setup.c | 8 +++--- arch/x86/mm/memblock.c | 52 ++++++++++++++++++++++++++++++++++++++++ 3 files changed, 58 insertions(+), 4 deletions(-) Index: linux-2.6/arch/x86/mm/memblock.c =================================================================== --- linux-2.6.orig/arch/x86/mm/memblock.c +++ linux-2.6/arch/x86/mm/memblock.c @@ -352,3 +352,55 @@ u64 __init memblock_x86_hole_size(u64 st return end - start - ((u64)ram << PAGE_SHIFT); } + +/* Check for already reserved areas */ +static inline bool __init check_with_memblock_reserved(u64 *addrp, u64 size, u64 align) +{ + u64 addr = *addrp; + bool changed = false; + struct memblock_region *r; +again: + for_each_memblock(reserved, r) { + if ((addr + size) > r->base && addr < (r->base + r->size)) { + addr = round_up(r->base + r->size, align); + changed = true; + goto again; + } + } + + if (changed) + *addrp = addr; + + return changed; +} + +/* + * Find a free area with specified alignment in a specific range from bottom up + */ +u64 __init memblock_find_in_range_lowest(u64 start, u64 end, u64 size, u64 align) +{ + struct memblock_region *r; + + for_each_memblock(memory, r) { + u64 ei_start = r->base; + u64 ei_last = ei_start + r->size; + u64 addr, last; + + addr = round_up(ei_start, align); + if (addr < start) + addr = round_up(start, align); + if (addr >= ei_last) + continue; + while (check_with_memblock_reserved(&addr, size, align) && addr+size <= ei_last) + ; + last = addr + size; + if (last > ei_last) + continue; + if (last > end) + continue; + + return addr; + } + + return MEMBLOCK_ERROR; +} Index: linux-2.6/arch/x86/include/asm/memblock.h =================================================================== --- linux-2.6.orig/arch/x86/include/asm/memblock.h +++ linux-2.6/arch/x86/include/asm/memblock.h @@ -18,4 +18,6 @@ u64 memblock_x86_find_in_range_node(int u64 memblock_x86_free_memory_in_range(u64 addr, u64 limit); u64 memblock_x86_memory_in_range(u64 addr, u64 limit); +u64 memblock_find_in_range_lowest(u64 start, u64 end, u64 size, u64 align); + #endif Index: linux-2.6/arch/x86/kernel/setup.c =================================================================== --- linux-2.6.orig/arch/x86/kernel/setup.c +++ linux-2.6/arch/x86/kernel/setup.c @@ -518,8 +518,8 @@ static void __init reserve_crashkernel(v if (crash_base <= 0) { const unsigned long long alignment = 16<<20; /* 16M */ - crash_base = memblock_find_in_range(alignment, ULONG_MAX, crash_size, - alignment); + crash_base = memblock_find_in_range_lowest(alignment, + ULONG_MAX, crash_size, alignment); if (crash_base == MEMBLOCK_ERROR) { pr_info("crashkernel reservation failed - No suitable area found.\n"); return; @@ -527,8 +527,8 @@ static void __init reserve_crashkernel(v } else { unsigned long long start; - start = memblock_find_in_range(crash_base, ULONG_MAX, crash_size, - 1<<20); + start = memblock_find_in_range(crash_base, + crash_base + crash_size, crash_size, 1<<20); if (start != crash_base) { pr_info("crashkernel reservation failed - memory is in use.\n"); return;