diff options
Diffstat (limited to 'common/recipes-kernel/linux/linux-yocto-4.9.21/0019-kaiser-vmstat-show-NR_KAISERTABLE-as-nr_overhead.patch')
| -rw-r--r-- | common/recipes-kernel/linux/linux-yocto-4.9.21/0019-kaiser-vmstat-show-NR_KAISERTABLE-as-nr_overhead.patch | 122 |
1 files changed, 0 insertions, 122 deletions
diff --git a/common/recipes-kernel/linux/linux-yocto-4.9.21/0019-kaiser-vmstat-show-NR_KAISERTABLE-as-nr_overhead.patch b/common/recipes-kernel/linux/linux-yocto-4.9.21/0019-kaiser-vmstat-show-NR_KAISERTABLE-as-nr_overhead.patch deleted file mode 100644 index 8b73b30f..00000000 --- a/common/recipes-kernel/linux/linux-yocto-4.9.21/0019-kaiser-vmstat-show-NR_KAISERTABLE-as-nr_overhead.patch +++ /dev/null @@ -1,122 +0,0 @@ -From c5cd21271fbd17c27cb4dbfa0a70b9108529d184 Mon Sep 17 00:00:00 2001 -From: Hugh Dickins <hughd@google.com> -Date: Sat, 9 Sep 2017 21:27:32 -0700 -Subject: [PATCH 019/103] kaiser: vmstat show NR_KAISERTABLE as nr_overhead - -The kaiser update made an interesting choice, never to free any shadow -page tables. Contention on global spinlock was worrying, particularly -with it held across page table scans when freeing. Something had to be -done: I was going to add refcounting; but simply never to free them is -an appealing choice, minimizing contention without complicating the code -(the more a page table is found already, the less the spinlock is used). - -But leaking pages in this way is also a worry: can we get away with it? -At the very least, we need a count to show how bad it actually gets: -in principle, one might end up wasting about 1/256 of memory that way -(1/512 for when direct-mapped pages have to be user-mapped, plus 1/512 -for when they are user-mapped from the vmalloc area on another occasion -(but we don't have vmalloc'ed stacks, so only large ldts are vmalloc'ed). - -Add per-cpu stat NR_KAISERTABLE: including 256 at startup for the -shared pgd entries, and 1 for each intermediate page table added -thereafter for user-mapping - but leave out the 1 per mm, for its -shadow pgd, because that distracts from the monotonic increase. -Shown in /proc/vmstat as nr_overhead (0 if kaiser not enabled). - -In practice, it doesn't look so bad so far: more like 1/12000 after -nine hours of gtests below; and movable pageblock segregation should -tend to cluster the kaiser tables into a subset of the address space -(if not, they will be bad for compaction too). But production may -tell a different story: keep an eye on this number, and bring back -lighter freeing if it gets out of control (maybe a shrinker). - -["nr_overhead" should of course say "nr_kaisertable", if it needs -to stay; but for the moment we are being coy, preferring that when -Joe Blow notices a new line in his /proc/vmstat, he does not get -too curious about what this "kaiser" stuff might be.] - -Signed-off-by: Hugh Dickins <hughd@google.com> -Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> ---- - arch/x86/mm/kaiser.c | 16 +++++++++++----- - include/linux/mmzone.h | 3 ++- - mm/vmstat.c | 1 + - 3 files changed, 14 insertions(+), 6 deletions(-) - -diff --git a/arch/x86/mm/kaiser.c b/arch/x86/mm/kaiser.c -index 7a7e850..bd22ef5 100644 ---- a/arch/x86/mm/kaiser.c -+++ b/arch/x86/mm/kaiser.c -@@ -121,9 +121,11 @@ static pte_t *kaiser_pagetable_walk(unsigned long address, bool is_atomic) - if (!new_pmd_page) - return NULL; - spin_lock(&shadow_table_allocation_lock); -- if (pud_none(*pud)) -+ if (pud_none(*pud)) { - set_pud(pud, __pud(_KERNPG_TABLE | __pa(new_pmd_page))); -- else -+ __inc_zone_page_state(virt_to_page((void *) -+ new_pmd_page), NR_KAISERTABLE); -+ } else - free_page(new_pmd_page); - spin_unlock(&shadow_table_allocation_lock); - } -@@ -139,9 +141,11 @@ static pte_t *kaiser_pagetable_walk(unsigned long address, bool is_atomic) - if (!new_pte_page) - return NULL; - spin_lock(&shadow_table_allocation_lock); -- if (pmd_none(*pmd)) -+ if (pmd_none(*pmd)) { - set_pmd(pmd, __pmd(_KERNPG_TABLE | __pa(new_pte_page))); -- else -+ __inc_zone_page_state(virt_to_page((void *) -+ new_pte_page), NR_KAISERTABLE); -+ } else - free_page(new_pte_page); - spin_unlock(&shadow_table_allocation_lock); - } -@@ -205,11 +209,13 @@ static void __init kaiser_init_all_pgds(void) - pgd = native_get_shadow_pgd(pgd_offset_k((unsigned long )0)); - for (i = PTRS_PER_PGD / 2; i < PTRS_PER_PGD; i++) { - pgd_t new_pgd; -- pud_t *pud = pud_alloc_one(&init_mm, PAGE_OFFSET + i * PGDIR_SIZE); -+ pud_t *pud = pud_alloc_one(&init_mm, -+ PAGE_OFFSET + i * PGDIR_SIZE); - if (!pud) { - WARN_ON(1); - break; - } -+ inc_zone_page_state(virt_to_page(pud), NR_KAISERTABLE); - new_pgd = __pgd(_KERNPG_TABLE |__pa(pud)); - /* - * Make sure not to stomp on some other pgd entry. -diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h -index 7e273e2..0547d4f 100644 ---- a/include/linux/mmzone.h -+++ b/include/linux/mmzone.h -@@ -124,8 +124,9 @@ enum zone_stat_item { - NR_SLAB_UNRECLAIMABLE, - NR_PAGETABLE, /* used for pagetables */ - NR_KERNEL_STACK_KB, /* measured in KiB */ -- /* Second 128 byte cacheline */ -+ NR_KAISERTABLE, - NR_BOUNCE, -+ /* Second 128 byte cacheline */ - #if IS_ENABLED(CONFIG_ZSMALLOC) - NR_ZSPAGES, /* allocated in zsmalloc */ - #endif -diff --git a/mm/vmstat.c b/mm/vmstat.c -index 604f26a..6a088df 100644 ---- a/mm/vmstat.c -+++ b/mm/vmstat.c -@@ -932,6 +932,7 @@ const char * const vmstat_text[] = { - "nr_slab_unreclaimable", - "nr_page_table_pages", - "nr_kernel_stack", -+ "nr_overhead", - "nr_bounce", - #if IS_ENABLED(CONFIG_ZSMALLOC) - "nr_zspages", --- -2.7.4 - |