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authorAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>2022-02-11 09:52:15 +0300
committerMichael Ellerman <mpe@ellerman.id.au>2022-02-12 14:47:44 +0300
commit2354ad252b66695be02f4acd18e37bf6264f0464 (patch)
tree6b10534aa75e29db5c462755289884dbe794ffe3 /arch/powerpc/mm
parent2504e5b9827f7fc76ed0e4593adc852ac7a19851 (diff)
downloadlinux-2354ad252b66695be02f4acd18e37bf6264f0464.tar.xz
powerpc/mm: Update default hugetlb size early
commit: d9c234005227 ("Do not depend on MAX_ORDER when grouping pages by mobility") introduced pageblock_order which will be used to group pages better. The kernel now groups pages based on the value of HPAGE_SHIFT. Hence HPAGE_SHIFT should be set before we call set_pageblock_order. set_pageblock_order happens early in the boot and default hugetlb page size should be initialized before that to compute the right pageblock_order value. Currently, default hugetlbe page size is set via arch_initcalls which happens late in the boot as shown via the below callstack: [c000000007383b10] [c000000001289328] hugetlbpage_init+0x2b8/0x2f8 [c000000007383bc0] [c0000000012749e4] do_one_initcall+0x14c/0x320 [c000000007383c90] [c00000000127505c] kernel_init_freeable+0x410/0x4e8 [c000000007383da0] [c000000000012664] kernel_init+0x30/0x15c [c000000007383e10] [c00000000000cf14] ret_from_kernel_thread+0x5c/0x64 and the pageblock_order initialization is done early during the boot. [c0000000018bfc80] [c0000000012ae120] set_pageblock_order+0x50/0x64 [c0000000018bfca0] [c0000000012b3d94] sparse_init+0x188/0x268 [c0000000018bfd60] [c000000001288bfc] initmem_init+0x28c/0x328 [c0000000018bfe50] [c00000000127b370] setup_arch+0x410/0x480 [c0000000018bfed0] [c00000000127401c] start_kernel+0xb8/0x934 [c0000000018bff90] [c00000000000d984] start_here_common+0x1c/0x98 delaying default hugetlb page size initialization implies the kernel will initialize pageblock_order to (MAX_ORDER - 1) which is not an optimal value for mobility grouping. IIUC we always had this issue. But it was not a problem for hash translation mode because (MAX_ORDER - 1) is the same as HUGETLB_PAGE_ORDER (8) in the case of hash (16MB). With radix, HUGETLB_PAGE_ORDER will be 5 (2M size) and hence pageblock_order should be 5 instead of 8. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220211065215.101767-1-aneesh.kumar@linux.ibm.com
Diffstat (limited to 'arch/powerpc/mm')
-rw-r--r--arch/powerpc/mm/book3s64/hugetlbpage.c2
-rw-r--r--arch/powerpc/mm/hugetlbpage.c5
-rw-r--r--arch/powerpc/mm/init_64.c4
3 files changed, 6 insertions, 5 deletions
diff --git a/arch/powerpc/mm/book3s64/hugetlbpage.c b/arch/powerpc/mm/book3s64/hugetlbpage.c
index ea8f83afb0ae..3bc0eb21b2a0 100644
--- a/arch/powerpc/mm/book3s64/hugetlbpage.c
+++ b/arch/powerpc/mm/book3s64/hugetlbpage.c
@@ -150,7 +150,7 @@ void huge_ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned long addr
set_huge_pte_at(vma->vm_mm, addr, ptep, pte);
}
-void __init hugetlbpage_init_default(void)
+void __init hugetlbpage_init_defaultsize(void)
{
/* Set default large page size. Currently, we pick 16M or 1M
* depending on what is available
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index ddead41e2194..b642a5a8668f 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -664,10 +664,7 @@ static int __init hugetlbpage_init(void)
configured = true;
}
- if (configured) {
- if (IS_ENABLED(CONFIG_HUGETLB_PAGE_SIZE_VARIABLE))
- hugetlbpage_init_default();
- } else
+ if (!configured)
pr_info("Failed to initialize. Disabling HugeTLB");
return 0;
diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index 35f46bf54281..83c0ee9fbf05 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -59,6 +59,7 @@
#include <asm/sections.h>
#include <asm/iommu.h>
#include <asm/vdso.h>
+#include <asm/hugetlb.h>
#include <mm/mmu_decl.h>
@@ -513,6 +514,9 @@ void __init mmu_early_init_devtree(void)
} else
hash__early_init_devtree();
+ if (IS_ENABLED(CONFIG_HUGETLB_PAGE_SIZE_VARIABLE))
+ hugetlbpage_init_defaultsize();
+
if (!(cur_cpu_spec->mmu_features & MMU_FTR_HPTE_TABLE) &&
!(cur_cpu_spec->mmu_features & MMU_FTR_TYPE_RADIX))
panic("kernel does not support any MMU type offered by platform");