Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757014Ab3CSPGC (ORCPT ); Tue, 19 Mar 2013 11:06:02 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:20351 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932081Ab3CSPGA (ORCPT ); Tue, 19 Mar 2013 11:06:00 -0400 From: Yinghai Lu To: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" Cc: WANG Chao , Vivek Goyal , "Eric W. Biederman" , linux-kernel@vger.kernel.org, Yinghai Lu Subject: [PATCH v5] x86, kdump: Set crashkernel_low automatically Date: Tue, 19 Mar 2013 08:05:26 -0700 Message-Id: <1363705526-3197-1-git-send-email-yinghai@kernel.org> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <20130319133326.GB3872@redhat.com> References: <20130319133326.GB3872@redhat.com> X-Source-IP: ucsinet21.oracle.com [156.151.31.93] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5913 Lines: 168 Chao said that kdump does does work well on his system on 3.8 without extra parameter, even iommu does not work with kdump. And now have to append crashkernel_low=Y in first kernel to make kdump work. We have now modified crashkernel=X to allocate memory beyong 4G (if available) and do not allocate low range for crashkernel if the user does not specify that with crashkernel_low=Y. This causes regression if iommu is not enabled. Without iommu, swiotlb needs to be setup in first 4G and there is no low memory available to second kernel. Set crashkernel_low automatically if the user does not specify that. For system that does support IOMMU with kdump properly, user could specify crashkernel_low=0 to save that 72M low ram. -v3: add swiotlb_size() according to Konrad. -v4: add comments what 8M is for according to hpa. also update more crashkernel_low= in kernel-parameters.txt -v5: update changelog according to Vivek. Reported-by: WANG Chao Tested-by: WANG Chao Signed-off-by: Yinghai Lu --- Documentation/kernel-parameters.txt | 15 ++++++++++++--- arch/x86/kernel/setup.c | 20 +++++++++++++++++--- include/linux/swiotlb.h | 1 + lib/swiotlb.c | 19 +++++++++++++++---- 4 files changed, 45 insertions(+), 10 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 @@ -521,19 +521,33 @@ static void __init reserve_crashkernel_l unsigned long long low_base = 0, low_size = 0; unsigned long total_low_mem; unsigned long long base; + bool auto_set = false; int ret; total_low_mem = memblock_mem_size(1UL<<(32-PAGE_SHIFT)); ret = parse_crashkernel_low(boot_command_line, total_low_mem, &low_size, &base); - if (ret != 0 || low_size <= 0) - return; + if (ret != 0) { + /* + * two parts from lib/swiotlb.c: + * swiotlb size: user specified with swiotlb= or default. + * swiotlb overflow buffer: now is hardcoded to 32k, + * round to 8M to cover more others. + */ + low_size = swiotlb_size_or_default() + (8UL<<20); + auto_set = true; + } else { + /* passed with crashkernel_low=0 ? */ + if (!low_size) + return; + } low_base = memblock_find_in_range(low_size, (1ULL<<32), low_size, alignment); if (!low_base) { - pr_info("crashkernel low reservation failed - No suitable area found.\n"); + if (!auto_set) + pr_info("crashkernel low reservation failed - No suitable area found.\n"); return; } Index: linux-2.6/include/linux/swiotlb.h =================================================================== --- linux-2.6.orig/include/linux/swiotlb.h +++ linux-2.6/include/linux/swiotlb.h @@ -25,6 +25,7 @@ extern int swiotlb_force; extern void swiotlb_init(int verbose); int swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose); extern unsigned long swiotlb_nr_tbl(void); +unsigned long swiotlb_size_or_default(void); extern int swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs); /* Index: linux-2.6/lib/swiotlb.c =================================================================== --- linux-2.6.orig/lib/swiotlb.c +++ linux-2.6/lib/swiotlb.c @@ -105,9 +105,9 @@ setup_io_tlb_npages(char *str) if (!strcmp(str, "force")) swiotlb_force = 1; - return 1; + return 0; } -__setup("swiotlb=", setup_io_tlb_npages); +early_param("swiotlb", setup_io_tlb_npages); /* make io_tlb_overflow tunable too? */ unsigned long swiotlb_nr_tbl(void) @@ -115,6 +115,18 @@ unsigned long swiotlb_nr_tbl(void) return io_tlb_nslabs; } EXPORT_SYMBOL_GPL(swiotlb_nr_tbl); + +/* default to 64MB */ +#define IO_TLB_DEFAULT_SIZE (64UL<<20) +unsigned long swiotlb_size_or_default(void) +{ + unsigned long size; + + size = io_tlb_nslabs << IO_TLB_SHIFT; + + return size ? size : (IO_TLB_DEFAULT_SIZE); +} + /* Note that this doesn't work with highmem page */ static dma_addr_t swiotlb_virt_to_bus(struct device *hwdev, volatile void *address) @@ -188,8 +200,7 @@ int __init swiotlb_init_with_tbl(char *t void __init swiotlb_init(int verbose) { - /* default to 64MB */ - size_t default_size = 64UL<<20; + size_t default_size = IO_TLB_DEFAULT_SIZE; unsigned char *vstart; unsigned long bytes; Index: linux-2.6/Documentation/kernel-parameters.txt =================================================================== --- linux-2.6.orig/Documentation/kernel-parameters.txt +++ linux-2.6/Documentation/kernel-parameters.txt @@ -596,9 +596,6 @@ bytes respectively. Such letter suffixes is selected automatically. Check Documentation/kdump/kdump.txt for further details. - crashkernel_low=size[KMG] - [KNL, x86] parts under 4G. - crashkernel=range1:size1[,range2:size2,...][@offset] [KNL] Same as above, but depends on the memory in the running system. The syntax of range is @@ -606,6 +603,18 @@ bytes respectively. Such letter suffixes a memory unit (amount[KMG]). See also Documentation/kdump/kdump.txt for an example. + crashkernel_low=size[KMG] + [KNL, x86_64] range under 4G. When crashkernel= is + passed, kernel allocate physical memory region + above 4G, that cause second kernel crash on system + that need swiotlb later. Kernel would try to allocate + some region below 4G automatically. This one let + user to specify own low range under 4G for second + kernel instead. + 0: to disable low allocation on systems that do not + need swiotlb, that will save 72M low ram in first + kernel. + cs89x0_dma= [HW,NET] Format: -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/