| Message ID | 152336768322.8374.8580280567534579046.stgit@hbathini.in.ibm.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 8597538712ebd90bc83dfb0b3b40398a0c53ad5b |
| Headers | show |
| Series | [v2,1/2] powerpc/fadump: exclude memory holes while reserving memory in second kernel | expand |
On 04/10/2018 07:11 PM, Hari Bathini wrote: > FADump capture kernel boots in restricted memory environment preserving > the context of previous kernel to save vmcore. Supporting hugepages in > such environment makes things unnecessarily complicated, as hugepages > need memory set aside for them. This means most of the capture kernel's > memory is used in supporting hugepages. In most cases, this results in > out-of-memory issues while booting FADump capture kernel. But hugepages > are not of much use in capture kernel whose only job is to save vmcore. > So, disabling hugepages support, when fadump is active, is a reliable > solution for the out of memory issues. Introducing a flag variable to > disable HugeTLB support when fadump is active. > > Signed-off-by: Hari Bathini <hbathini@linux.vnet.ibm.com> > --- > > Changes in v2: > * Introduce a hugetlb_disabled flag to enable/disable hugepage support & > use that flag to disable hugepage support when fadump is active. Looks good to me. Reviewed-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> > > > arch/powerpc/include/asm/page.h | 1 + > arch/powerpc/kernel/fadump.c | 8 ++++++++ > arch/powerpc/mm/hash_utils_64.c | 6 ++++-- > arch/powerpc/mm/hugetlbpage.c | 7 +++++++ > 4 files changed, 20 insertions(+), 2 deletions(-) > > diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h > index 8da5d4c..40aee93 100644 > --- a/arch/powerpc/include/asm/page.h > +++ b/arch/powerpc/include/asm/page.h > @@ -39,6 +39,7 @@ > > #ifndef __ASSEMBLY__ > #ifdef CONFIG_HUGETLB_PAGE > +extern bool hugetlb_disabled; > extern unsigned int HPAGE_SHIFT; > #else > #define HPAGE_SHIFT PAGE_SHIFT > diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c > index bea8d5f..8ceabef4 100644 > --- a/arch/powerpc/kernel/fadump.c > +++ b/arch/powerpc/kernel/fadump.c > @@ -402,6 +402,14 @@ int __init fadump_reserve_mem(void) > if (fw_dump.dump_active) { > pr_info("Firmware-assisted dump is active.\n"); > > +#ifdef CONFIG_HUGETLB_PAGE > + /* > + * FADump capture kernel doesn't care much about hugepages. > + * In fact, handling hugepages in capture kernel is asking for > + * trouble. So, disable HugeTLB support when fadump is active. > + */ > + hugetlb_disabled = true; > +#endif > /* > * If last boot has crashed then reserve all the memory > * above boot_memory_size so that we don't touch it until > diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c > index cf290d41..eab8f1d 100644 > --- a/arch/powerpc/mm/hash_utils_64.c > +++ b/arch/powerpc/mm/hash_utils_64.c > @@ -571,8 +571,10 @@ static void __init htab_scan_page_sizes(void) > } > > #ifdef CONFIG_HUGETLB_PAGE > - /* Reserve 16G huge page memory sections for huge pages */ > - of_scan_flat_dt(htab_dt_scan_hugepage_blocks, NULL); > + if (!hugetlb_disabled) { > + /* Reserve 16G huge page memory sections for huge pages */ > + of_scan_flat_dt(htab_dt_scan_hugepage_blocks, NULL); > + } > #endif /* CONFIG_HUGETLB_PAGE */ > } > > diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c > index 876da2b..18c080a 100644 > --- a/arch/powerpc/mm/hugetlbpage.c > +++ b/arch/powerpc/mm/hugetlbpage.c > @@ -35,6 +35,8 @@ > #define PAGE_SHIFT_16M 24 > #define PAGE_SHIFT_16G 34 > > +bool hugetlb_disabled = false; > + > unsigned int HPAGE_SHIFT; > EXPORT_SYMBOL(HPAGE_SHIFT); > > @@ -653,6 +655,11 @@ static int __init hugetlbpage_init(void) > { > int psize; > > + if (hugetlb_disabled) { > + pr_info("HugeTLB support is disabled!\n"); > + return 0; > + } > + > #if !defined(CONFIG_PPC_FSL_BOOK3E) && !defined(CONFIG_PPC_8xx) > if (!radix_enabled() && !mmu_has_feature(MMU_FTR_16M_PAGE)) > return -ENODEV; >
diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h index 8da5d4c..40aee93 100644 --- a/arch/powerpc/include/asm/page.h +++ b/arch/powerpc/include/asm/page.h @@ -39,6 +39,7 @@ #ifndef __ASSEMBLY__ #ifdef CONFIG_HUGETLB_PAGE +extern bool hugetlb_disabled; extern unsigned int HPAGE_SHIFT; #else #define HPAGE_SHIFT PAGE_SHIFT diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c index bea8d5f..8ceabef4 100644 --- a/arch/powerpc/kernel/fadump.c +++ b/arch/powerpc/kernel/fadump.c @@ -402,6 +402,14 @@ int __init fadump_reserve_mem(void) if (fw_dump.dump_active) { pr_info("Firmware-assisted dump is active.\n"); +#ifdef CONFIG_HUGETLB_PAGE + /* + * FADump capture kernel doesn't care much about hugepages. + * In fact, handling hugepages in capture kernel is asking for + * trouble. So, disable HugeTLB support when fadump is active. + */ + hugetlb_disabled = true; +#endif /* * If last boot has crashed then reserve all the memory * above boot_memory_size so that we don't touch it until diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c index cf290d41..eab8f1d 100644 --- a/arch/powerpc/mm/hash_utils_64.c +++ b/arch/powerpc/mm/hash_utils_64.c @@ -571,8 +571,10 @@ static void __init htab_scan_page_sizes(void) } #ifdef CONFIG_HUGETLB_PAGE - /* Reserve 16G huge page memory sections for huge pages */ - of_scan_flat_dt(htab_dt_scan_hugepage_blocks, NULL); + if (!hugetlb_disabled) { + /* Reserve 16G huge page memory sections for huge pages */ + of_scan_flat_dt(htab_dt_scan_hugepage_blocks, NULL); + } #endif /* CONFIG_HUGETLB_PAGE */ } diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c index 876da2b..18c080a 100644 --- a/arch/powerpc/mm/hugetlbpage.c +++ b/arch/powerpc/mm/hugetlbpage.c @@ -35,6 +35,8 @@ #define PAGE_SHIFT_16M 24 #define PAGE_SHIFT_16G 34 +bool hugetlb_disabled = false; + unsigned int HPAGE_SHIFT; EXPORT_SYMBOL(HPAGE_SHIFT); @@ -653,6 +655,11 @@ static int __init hugetlbpage_init(void) { int psize; + if (hugetlb_disabled) { + pr_info("HugeTLB support is disabled!\n"); + return 0; + } + #if !defined(CONFIG_PPC_FSL_BOOK3E) && !defined(CONFIG_PPC_8xx) if (!radix_enabled() && !mmu_has_feature(MMU_FTR_16M_PAGE)) return -ENODEV;
FADump capture kernel boots in restricted memory environment preserving the context of previous kernel to save vmcore. Supporting hugepages in such environment makes things unnecessarily complicated, as hugepages need memory set aside for them. This means most of the capture kernel's memory is used in supporting hugepages. In most cases, this results in out-of-memory issues while booting FADump capture kernel. But hugepages are not of much use in capture kernel whose only job is to save vmcore. So, disabling hugepages support, when fadump is active, is a reliable solution for the out of memory issues. Introducing a flag variable to disable HugeTLB support when fadump is active. Signed-off-by: Hari Bathini <hbathini@linux.vnet.ibm.com> --- Changes in v2: * Introduce a hugetlb_disabled flag to enable/disable hugepage support & use that flag to disable hugepage support when fadump is active. arch/powerpc/include/asm/page.h | 1 + arch/powerpc/kernel/fadump.c | 8 ++++++++ arch/powerpc/mm/hash_utils_64.c | 6 ++++-- arch/powerpc/mm/hugetlbpage.c | 7 +++++++ 4 files changed, 20 insertions(+), 2 deletions(-)