First question is if Calgary even exists anymore and if so if someone actually cares about it enough to maintain it. On February 24, 2014 6:58:41 AM PST, WANG Chao <chaowang at redhat.com> wrote: >On 02/24/14 at 11:38am, Thomas Renninger wrote: >> On Thursday, February 20, 2014 05:28:28 PM WANG Chao wrote: >> > Hi, All >> > >> > When kaslr comes in and kdump is broken, it seems about the right >time to >> > use E820 instead of memmap=exactmap to pass memmap for kdump for >the >> > default memmap passing mechanism: >> > >http://lists.infradead.org/pipermail/kexec/2014-February/011048.html >> > >> > Unfortunately, saved_max_pfn still got its user out there (calgry >pci, it >> > looks like the only one). So for backward compatibility, I'm >introducing a >> > new option --pass-memmap-cmdline to force kexec-tools to pass >> > memmap=exactmap, the old way. >> The saved_max_pfn usage is calgary pci looks bad/wrong and I wonder: >> - whether this is still worth touching, so that the old mechanism: >> --pass-memmap-cmdline could vanish in the one or other year and >need >> not to be carried forever >> I tried to find such a machine, but couldn't find anything mentioning >calgary >> in quite some machines' dmesg. >> >> Approaches to avoid saved_max_pfn in calgary case: >> 1) If done correctly from the beginning, the TCE table size would >have >> been exposed via /sys and kexec-tools could simply add: >> calgary="128k|512K...|8M" which is already caught by pci-calgary >and >> saved_max_pfn is not needed/touched anymore. >> -> Disadvantage: needs a new sysfs entry >> 2) When finding max_pfn for calgary table size usage, we could try >in >> kdump case to use the highest memory (RAM or RESERVED) showing >up >> in e820 map. > >How could this replace saved_max_pfn? The highest memory in kdump can't >necessarily be the real ram size. In kdump, RAM range is just part of >the real >ram, not mentioning we don't pass RESERVED range to kdump E820. > >Thanks >WANG Chao > >> >> Please find below a patch which would eleminate the last >saved_max_pfn >> user. Unfortunately I could not find a calgary system to test this >on. >> >> Be aware: I could not test this. >> If someone tells me for what kind of machine (and BIOS stuff >enabled?) >> I should look for, I can try to search for such a platform. >> >> Something else: There is quite some duplicate code in kexec-tools >when it >> is about retrieving the e820 table info (normal kexec vs kdump). >> Did you see my cleanups I posted long ago? Do you plan to still clean >up >> a bit after this series? > >Yes, I saw them and find some of them are pretty useful for this >patchset. I suppose some cleanups can be done later. Feel free to clean >up after this patchset is settled. > >> >> Thomas >> >> >> >> X86: Eliminate saved_max_pfn user in pci-calgary and remove the >unused variable >> >> Searching for the highest value of RAM and RESERVED memory in kdump >case >> should be the same as max_pfn of the original kernel. >> At least this is always the case as long as type usable RAM is the >highest >> entry in original e820 map. >> >> Signed-off-by: Thomas Renninger <trenn at suse.de> >> >> diff --git a/arch/x86/include/asm/e820.h >b/arch/x86/include/asm/e820.h >> index 779c2ef..712173e 100644 >> --- a/arch/x86/include/asm/e820.h >> +++ b/arch/x86/include/asm/e820.h >> @@ -49,6 +49,7 @@ static inline void early_memtest(unsigned long >start, unsigned long end) >> #endif >> >> extern unsigned long e820_end_of_ram_pfn(void); >> +extern unsigned long e820_end_of_e820_pfn(void); >> extern unsigned long e820_end_of_low_ram_pfn(void); >> extern u64 early_reserve_e820(u64 sizet, u64 align); >> >> diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c >> index 988c00a..699e8fe 100644 >> --- a/arch/x86/kernel/e820.c >> +++ b/arch/x86/kernel/e820.c >> @@ -757,7 +757,7 @@ u64 __init early_reserve_e820(u64 size, u64 >align) >> /* >> * Find the highest page frame number we have available >> */ >> -static unsigned long __init e820_end_pfn(unsigned long limit_pfn, >unsigned type) >> +unsigned long __init e820_end_pfn(unsigned long limit_pfn, unsigned >type) >> { >> int i; >> unsigned long last_pfn = 0; >> @@ -796,6 +796,12 @@ unsigned long __init e820_end_of_ram_pfn(void) >> return e820_end_pfn(MAX_ARCH_PFN, E820_RAM); >> } >> >> +unsigned long __init e820_end_of_e820_pfn(void) >> +{ >> + return max(e820_end_pfn(MAX_ARCH_PFN, E820_RAM), >> + e820_end_pfn(MAX_ARCH_PFN, E820_RESERVED); >> +} >> + >> unsigned long __init e820_end_of_low_ram_pfn(void) >> { >> return e820_end_pfn(1UL<<(32 - PAGE_SHIFT), E820_RAM); >> @@ -847,14 +853,6 @@ static int __init parse_memmap_one(char *p) >> return -EINVAL; >> >> if (!strncmp(p, "exactmap", 8)) { >> -#ifdef CONFIG_CRASH_DUMP >> - /* >> - * If we are doing a crash dump, we still need to know >> - * the real mem size before original memory map is >> - * reset. >> - */ >> - saved_max_pfn = e820_end_of_ram_pfn(); >> -#endif >> e820.nr_map = 0; >> userdef = 1; >> return 0; >> diff --git a/arch/x86/kernel/pci-calgary_64.c >b/arch/x86/kernel/pci-calgary_64.c >> index 299d493..89ae766 100644 >> --- a/arch/x86/kernel/pci-calgary_64.c >> +++ b/arch/x86/kernel/pci-calgary_64.c >> @@ -1371,6 +1371,7 @@ int __init detect_calgary(void) >> unsigned long ptr; >> unsigned int offset, prev_offset; >> int ret; >> + unsigned long orig_max_pfn = max_pfn; >> >> /* >> * if the user specified iommu=off or iommu=soft or we found >> @@ -1418,8 +1419,10 @@ int __init detect_calgary(void) >> return -ENOMEM; >> } >> >> - specified_table_size = determine_tce_table_size((is_kdump_kernel() >? >> - saved_max_pfn : max_pfn) * PAGE_SIZE); >> + if (is_kdump_kernel()) >> + orig_max_pfn = e820_end_of_e820_pfn(); >> + specified_table_size = determine_tce_table_size(orig_max_pfn >> + * PAGE_SIZE); >> >> for (bus = 0; bus < MAX_PHB_BUS_NUM; bus++) { >> struct calgary_bus_info *info = &bus_info[bus]; >> diff --git a/include/linux/crash_dump.h b/include/linux/crash_dump.h >> index 7032518..bce4d97 100644 >> --- a/include/linux/crash_dump.h >> +++ b/include/linux/crash_dump.h >> @@ -87,5 +87,4 @@ extern void unregister_oldmem_pfn_is_ram(void); >> static inline int is_kdump_kernel(void) { return 0; } >> #endif /* CONFIG_CRASH_DUMP */ >> >> -extern unsigned long saved_max_pfn; >> #endif /* LINUX_CRASHDUMP_H */ >> diff --git a/kernel/crash_dump.c b/kernel/crash_dump.c >> index c766ee5..9d50486 100644 >> --- a/kernel/crash_dump.c >> +++ b/kernel/crash_dump.c >> @@ -5,12 +5,6 @@ >> #include <linux/export.h> >> >> /* >> - * If we have booted due to a crash, max_pfn will be a very low >value. We need >> - * to know the amount of memory that the previous kernel used. >> - */ >> -unsigned long saved_max_pfn; >> - >> -/* >> * stores the physical address of elf header of crash image >> * >> * Note: elfcorehdr_addr is not just limited to vmcore. It is also >used by >> -- Sent from my mobile phone. Please pardon brevity and lack of formatting.
