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0fbebed682
If our first THP installation for an MM is via the set_pmd_at() done during khugepaged's collapsing we'll end up in tsb_grow() trying to do a GFP_KERNEL allocation with several locks held. Simply using GFP_ATOMIC in this situation is not the best option because we really can't have this fail, so we'd really like to keep this an order 0 GFP_KERNEL allocation if possible. Also, doing the TSB allocation from khugepaged is a really bad idea because we'll allocate it potentially from the wrong NUMA node in that context. So what we do is defer the hugepage TSB allocation until the first TLB miss we take on a hugepage. This is slightly tricky because we have to handle two unusual cases: 1) Taking the first hugepage TLB miss in the window trap handler. We'll call the winfix_trampoline when that is detected. 2) An initial TSB allocation via TLB miss races with a hugetlb fault on another cpu running the same MM. We handle this by unconditionally loading the TSB we see into the current cpu even if it's non-NULL at hugetlb_setup time. Reported-by: Meelis Roos <mroos@ut.ee> Signed-off-by: David S. Miller <davem@davemloft.net>
196 lines
4.0 KiB
C
196 lines
4.0 KiB
C
/* arch/sparc64/mm/tlb.c
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*
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* Copyright (C) 2004 David S. Miller <davem@redhat.com>
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/percpu.h>
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#include <linux/mm.h>
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#include <linux/swap.h>
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#include <linux/preempt.h>
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#include <asm/pgtable.h>
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#include <asm/pgalloc.h>
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#include <asm/tlbflush.h>
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#include <asm/cacheflush.h>
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#include <asm/mmu_context.h>
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#include <asm/tlb.h>
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/* Heavily inspired by the ppc64 code. */
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static DEFINE_PER_CPU(struct tlb_batch, tlb_batch);
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void flush_tlb_pending(void)
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{
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struct tlb_batch *tb = &get_cpu_var(tlb_batch);
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if (tb->tlb_nr) {
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flush_tsb_user(tb);
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if (CTX_VALID(tb->mm->context)) {
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#ifdef CONFIG_SMP
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smp_flush_tlb_pending(tb->mm, tb->tlb_nr,
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&tb->vaddrs[0]);
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#else
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__flush_tlb_pending(CTX_HWBITS(tb->mm->context),
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tb->tlb_nr, &tb->vaddrs[0]);
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#endif
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}
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tb->tlb_nr = 0;
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}
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put_cpu_var(tlb_batch);
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}
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static void tlb_batch_add_one(struct mm_struct *mm, unsigned long vaddr,
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bool exec)
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{
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struct tlb_batch *tb = &get_cpu_var(tlb_batch);
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unsigned long nr;
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vaddr &= PAGE_MASK;
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if (exec)
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vaddr |= 0x1UL;
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nr = tb->tlb_nr;
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if (unlikely(nr != 0 && mm != tb->mm)) {
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flush_tlb_pending();
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nr = 0;
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}
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if (nr == 0)
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tb->mm = mm;
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tb->vaddrs[nr] = vaddr;
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tb->tlb_nr = ++nr;
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if (nr >= TLB_BATCH_NR)
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flush_tlb_pending();
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put_cpu_var(tlb_batch);
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}
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void tlb_batch_add(struct mm_struct *mm, unsigned long vaddr,
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pte_t *ptep, pte_t orig, int fullmm)
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{
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if (tlb_type != hypervisor &&
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pte_dirty(orig)) {
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unsigned long paddr, pfn = pte_pfn(orig);
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struct address_space *mapping;
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struct page *page;
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if (!pfn_valid(pfn))
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goto no_cache_flush;
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page = pfn_to_page(pfn);
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if (PageReserved(page))
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goto no_cache_flush;
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/* A real file page? */
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mapping = page_mapping(page);
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if (!mapping)
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goto no_cache_flush;
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paddr = (unsigned long) page_address(page);
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if ((paddr ^ vaddr) & (1 << 13))
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flush_dcache_page_all(mm, page);
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}
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no_cache_flush:
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if (!fullmm)
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tlb_batch_add_one(mm, vaddr, pte_exec(orig));
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}
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#ifdef CONFIG_TRANSPARENT_HUGEPAGE
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static void tlb_batch_pmd_scan(struct mm_struct *mm, unsigned long vaddr,
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pmd_t pmd, bool exec)
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{
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unsigned long end;
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pte_t *pte;
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pte = pte_offset_map(&pmd, vaddr);
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end = vaddr + HPAGE_SIZE;
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while (vaddr < end) {
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if (pte_val(*pte) & _PAGE_VALID)
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tlb_batch_add_one(mm, vaddr, exec);
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pte++;
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vaddr += PAGE_SIZE;
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}
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pte_unmap(pte);
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}
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void set_pmd_at(struct mm_struct *mm, unsigned long addr,
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pmd_t *pmdp, pmd_t pmd)
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{
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pmd_t orig = *pmdp;
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*pmdp = pmd;
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if (mm == &init_mm)
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return;
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if ((pmd_val(pmd) ^ pmd_val(orig)) & PMD_ISHUGE) {
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if (pmd_val(pmd) & PMD_ISHUGE)
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mm->context.huge_pte_count++;
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else
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mm->context.huge_pte_count--;
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/* Do not try to allocate the TSB hash table if we
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* don't have one already. We have various locks held
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* and thus we'll end up doing a GFP_KERNEL allocation
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* in an atomic context.
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*
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* Instead, we let the first TLB miss on a hugepage
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* take care of this.
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*/
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}
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if (!pmd_none(orig)) {
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bool exec = ((pmd_val(orig) & PMD_HUGE_EXEC) != 0);
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addr &= HPAGE_MASK;
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if (pmd_val(orig) & PMD_ISHUGE)
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tlb_batch_add_one(mm, addr, exec);
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else
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tlb_batch_pmd_scan(mm, addr, orig, exec);
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}
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}
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void pgtable_trans_huge_deposit(struct mm_struct *mm, pgtable_t pgtable)
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{
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struct list_head *lh = (struct list_head *) pgtable;
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assert_spin_locked(&mm->page_table_lock);
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/* FIFO */
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if (!mm->pmd_huge_pte)
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INIT_LIST_HEAD(lh);
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else
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list_add(lh, (struct list_head *) mm->pmd_huge_pte);
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mm->pmd_huge_pte = pgtable;
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}
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pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm)
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{
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struct list_head *lh;
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pgtable_t pgtable;
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assert_spin_locked(&mm->page_table_lock);
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/* FIFO */
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pgtable = mm->pmd_huge_pte;
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lh = (struct list_head *) pgtable;
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if (list_empty(lh))
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mm->pmd_huge_pte = NULL;
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else {
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mm->pmd_huge_pte = (pgtable_t) lh->next;
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list_del(lh);
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}
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pte_val(pgtable[0]) = 0;
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pte_val(pgtable[1]) = 0;
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return pgtable;
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}
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#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
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