From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from rcsinet10.oracle.com ([148.87.113.121]) by bombadil.infradead.org with esmtps (Exim 4.72 #1 (Red Hat Linux)) id 1P0UQV-0007EG-E9 for kexec@lists.infradead.org; Tue, 28 Sep 2010 07:16:37 +0000 Message-ID: <4CA195D7.4010706@kernel.org> Date: Tue, 28 Sep 2010 00:14:31 -0700 From: Yinghai Lu MIME-Version: 1.0 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> <4CA16522.8060107@zytor.com> In-Reply-To: <4CA16522.8060107@zytor.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: kexec-bounces@lists.infradead.org Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: "H. Peter Anvin" Cc: Ingo Molnar , kexec , caiqian@redhat.com, Vivek Goyal , linux-kernel@vger.kernel.org On 09/27/2010 08:46 PM, H. Peter Anvin wrote: > 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. >> >> 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. >> > > No, it's just another crappy hack which is broken in the same way. It's > better than open-coding, but it's still a hack. > > The Right Thing[TM] to do is for kexec to communicate the topmost > address it wants to this code, so it has both the upper and the lower > boundaries available to it instead of just one. hope you are happy with this one. [PATCH -v5] 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. -v5: use DEFAULT_BZIMAGE_ADDR_MAX to limit area that could be used by bzImge. also second try for vmlinux or new kexec tools will use bzImage 64bit entry Reported-and-Bisected-by: CAI Qian Signed-off-by: Yinghai Lu --- arch/x86/kernel/setup.c | 24 ++++++++++++++++++------ 1 file changed, 18 insertions(+), 6 deletions(-) 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 @@ -501,6 +501,7 @@ static inline unsigned long long get_tot return total << PAGE_SHIFT; } +#define DEFAULT_BZIMAGE_ADDR_MAX 0x37FFFFFF static void __init reserve_crashkernel(void) { unsigned long long total_mem; @@ -518,17 +519,28 @@ 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); + /* + * Assume half crash_size is for bzImage + * kexec want bzImage is below DEFAULT_BZIMAGE_ADDR_MAX + */ + crash_base = memblock_find_in_range(alignment, + DEFAULT_BZIMAGE_ADDR_MAX + crash_size/2, + crash_size, alignment); + if (crash_base == MEMBLOCK_ERROR) { - pr_info("crashkernel reservation failed - No suitable area found.\n"); - return; + crash_base = memblock_find_in_range(alignment, + ULONG_MAX, crash_size, alignment); + + if (crash_base == MEMBLOCK_ERROR) { + pr_info("crashkernel reservation failed - No suitable area found.\n"); + return; + } } } 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; _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec