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74 lines
2.0 KiB
74 lines
2.0 KiB
Subject: be more aggressive about de-activating mm-s under destruction
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From: jbeulich@novell.com
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Patch-mainline: obsolete
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... by not only handling the current task on the CPU arch_exit_mmap()
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gets executed on, but also forcing remote CPUs to do so.
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--- head-2010-04-15.orig/arch/x86/mm/pgtable-xen.c 2010-04-15 11:47:53.000000000 +0200
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+++ head-2010-04-15/arch/x86/mm/pgtable-xen.c 2010-04-15 11:48:29.000000000 +0200
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@@ -1,6 +1,7 @@
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#include <linux/mm.h>
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#include <linux/gfp.h>
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#include <linux/module.h>
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+#include <linux/smp.h>
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#include <xen/features.h>
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#include <asm/pgalloc.h>
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#include <asm/pgtable.h>
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@@ -438,27 +439,44 @@ void arch_dup_mmap(struct mm_struct *old
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mm_pin(mm);
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}
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-void arch_exit_mmap(struct mm_struct *mm)
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+/*
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+ * We aggressively remove defunct pgd from cr3. We execute unmap_vmas() *much*
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+ * faster this way, as no hypercalls are needed for the page table updates.
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+ */
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+static void leave_active_mm(struct task_struct *tsk, struct mm_struct *mm)
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+ __releases(tsk->alloc_lock)
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{
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- struct task_struct *tsk = current;
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-
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- task_lock(tsk);
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-
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- /*
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- * We aggressively remove defunct pgd from cr3. We execute unmap_vmas()
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- * *much* faster this way, as no tlb flushes means bigger wrpt batches.
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- */
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if (tsk->active_mm == mm) {
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tsk->active_mm = &init_mm;
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atomic_inc(&init_mm.mm_count);
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switch_mm(mm, &init_mm, tsk);
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- atomic_dec(&mm->mm_count);
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- BUG_ON(atomic_read(&mm->mm_count) == 0);
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+ if (atomic_dec_and_test(&mm->mm_count))
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+ BUG();
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}
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task_unlock(tsk);
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+}
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+
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+static void _leave_active_mm(void *mm)
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+{
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+ struct task_struct *tsk = current;
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+
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+ if (spin_trylock(&tsk->alloc_lock))
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+ leave_active_mm(tsk, mm);
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+}
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+
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+void arch_exit_mmap(struct mm_struct *mm)
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+{
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+ struct task_struct *tsk = current;
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+
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+ task_lock(tsk);
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+ leave_active_mm(tsk, mm);
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+
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+ preempt_disable();
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+ smp_call_function_many(mm_cpumask(mm), _leave_active_mm, mm, 1);
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+ preempt_enable();
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if (PagePinned(virt_to_page(mm->pgd))
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&& atomic_read(&mm->mm_count) == 1
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