Messages in this thread Patch in this message | | | From | Ingo Molnar <> | Subject | [PATCH 09/12] x86/mm/pat/32: Remove pgd_list use from the PAT code | Date | Sat, 13 Jun 2015 11:49:12 +0200 |
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The 32-bit x86 PAT code uses __set_pmd_pte() to update pmds.
This uses pgd_list currently, but we don't need the global list as we can walk the task list under RCU.
(This code already holds the pgd_lock.)
Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <Waiman.Long@hp.com> Cc: linux-mm@kvack.org Signed-off-by: Ingo Molnar <mingo@kernel.org> --- arch/x86/mm/pageattr.c | 26 ++++++++++++++++++++------ 1 file changed, 20 insertions(+), 6 deletions(-)
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 997fc97e9072..4ff6a1808f1d 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -438,17 +438,31 @@ static void __set_pmd_pte(pte_t *kpte, unsigned long address, pte_t pte) set_pte_atomic(kpte, pte); #ifdef CONFIG_X86_32 if (!SHARED_KERNEL_PMD) { - struct page *page; + struct task_struct *g, *p; - list_for_each_entry(page, &pgd_list, lru) { + /* We are holding pgd_lock, which implies rcu_read_lock(): */ + + for_each_process_thread(g, p) { + struct mm_struct *mm; + spinlock_t *pgt_lock; pgd_t *pgd; pud_t *pud; pmd_t *pmd; - pgd = (pgd_t *)page_address(page) + pgd_index(address); - pud = pud_offset(pgd, address); - pmd = pmd_offset(pud, address); - set_pte_atomic((pte_t *)pmd, pte); + task_lock(p); + mm = p->mm; + if (mm) { + pgt_lock = &mm->page_table_lock; + spin_lock(pgt_lock); + + pgd = mm->pgd + pgd_index(address); + pud = pud_offset(pgd, address); + pmd = pmd_offset(pud, address); + set_pte_atomic((pte_t *)pmd, pte); + + spin_unlock(pgt_lock); + } + task_unlock(p); } } #endif -- 2.1.4
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