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https://github.com/edk2-porting/linux-next.git
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7a9cdebdcc
Jann Horn points out that the vmacache_flush_all() function is not only potentially expensive, it's buggy too. It also happens to be entirely unnecessary, because the sequence number overflow case can be avoided by simply making the sequence number be 64-bit. That doesn't even grow the data structures in question, because the other adjacent fields are already 64-bit. So simplify the whole thing by just making the sequence number overflow case go away entirely, which gets rid of all the complications and makes the code faster too. Win-win. [ Oleg Nesterov points out that the VMACACHE_FULL_FLUSHES statistics also just goes away entirely with this ] Reported-by: Jann Horn <jannh@google.com> Suggested-by: Will Deacon <will.deacon@arm.com> Acked-by: Davidlohr Bueso <dave@stgolabs.net> Cc: Oleg Nesterov <oleg@redhat.com> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
179 lines
4.5 KiB
C
179 lines
4.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* mm/debug.c
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*
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* mm/ specific debug routines.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/trace_events.h>
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#include <linux/memcontrol.h>
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#include <trace/events/mmflags.h>
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#include <linux/migrate.h>
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#include <linux/page_owner.h>
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#include "internal.h"
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char *migrate_reason_names[MR_TYPES] = {
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"compaction",
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"memory_failure",
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"memory_hotplug",
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"syscall_or_cpuset",
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"mempolicy_mbind",
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"numa_misplaced",
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"cma",
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};
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const struct trace_print_flags pageflag_names[] = {
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__def_pageflag_names,
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{0, NULL}
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};
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const struct trace_print_flags gfpflag_names[] = {
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__def_gfpflag_names,
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{0, NULL}
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};
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const struct trace_print_flags vmaflag_names[] = {
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__def_vmaflag_names,
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{0, NULL}
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};
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void __dump_page(struct page *page, const char *reason)
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{
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bool page_poisoned = PagePoisoned(page);
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int mapcount;
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/*
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* If struct page is poisoned don't access Page*() functions as that
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* leads to recursive loop. Page*() check for poisoned pages, and calls
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* dump_page() when detected.
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*/
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if (page_poisoned) {
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pr_emerg("page:%px is uninitialized and poisoned", page);
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goto hex_only;
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}
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/*
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* Avoid VM_BUG_ON() in page_mapcount().
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* page->_mapcount space in struct page is used by sl[aou]b pages to
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* encode own info.
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*/
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mapcount = PageSlab(page) ? 0 : page_mapcount(page);
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pr_emerg("page:%px count:%d mapcount:%d mapping:%px index:%#lx",
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page, page_ref_count(page), mapcount,
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page->mapping, page_to_pgoff(page));
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if (PageCompound(page))
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pr_cont(" compound_mapcount: %d", compound_mapcount(page));
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pr_cont("\n");
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BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
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pr_emerg("flags: %#lx(%pGp)\n", page->flags, &page->flags);
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hex_only:
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print_hex_dump(KERN_ALERT, "raw: ", DUMP_PREFIX_NONE, 32,
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sizeof(unsigned long), page,
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sizeof(struct page), false);
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if (reason)
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pr_alert("page dumped because: %s\n", reason);
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#ifdef CONFIG_MEMCG
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if (!page_poisoned && page->mem_cgroup)
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pr_alert("page->mem_cgroup:%px\n", page->mem_cgroup);
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#endif
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}
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void dump_page(struct page *page, const char *reason)
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{
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__dump_page(page, reason);
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dump_page_owner(page);
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}
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EXPORT_SYMBOL(dump_page);
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#ifdef CONFIG_DEBUG_VM
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void dump_vma(const struct vm_area_struct *vma)
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{
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pr_emerg("vma %px start %px end %px\n"
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"next %px prev %px mm %px\n"
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"prot %lx anon_vma %px vm_ops %px\n"
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"pgoff %lx file %px private_data %px\n"
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"flags: %#lx(%pGv)\n",
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vma, (void *)vma->vm_start, (void *)vma->vm_end, vma->vm_next,
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vma->vm_prev, vma->vm_mm,
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(unsigned long)pgprot_val(vma->vm_page_prot),
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vma->anon_vma, vma->vm_ops, vma->vm_pgoff,
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vma->vm_file, vma->vm_private_data,
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vma->vm_flags, &vma->vm_flags);
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}
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EXPORT_SYMBOL(dump_vma);
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void dump_mm(const struct mm_struct *mm)
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{
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pr_emerg("mm %px mmap %px seqnum %llu task_size %lu\n"
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#ifdef CONFIG_MMU
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"get_unmapped_area %px\n"
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#endif
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"mmap_base %lu mmap_legacy_base %lu highest_vm_end %lu\n"
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"pgd %px mm_users %d mm_count %d pgtables_bytes %lu map_count %d\n"
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"hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %lx\n"
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"pinned_vm %lx data_vm %lx exec_vm %lx stack_vm %lx\n"
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"start_code %lx end_code %lx start_data %lx end_data %lx\n"
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"start_brk %lx brk %lx start_stack %lx\n"
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"arg_start %lx arg_end %lx env_start %lx env_end %lx\n"
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"binfmt %px flags %lx core_state %px\n"
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#ifdef CONFIG_AIO
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"ioctx_table %px\n"
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#endif
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#ifdef CONFIG_MEMCG
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"owner %px "
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#endif
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"exe_file %px\n"
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#ifdef CONFIG_MMU_NOTIFIER
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"mmu_notifier_mm %px\n"
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#endif
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#ifdef CONFIG_NUMA_BALANCING
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"numa_next_scan %lu numa_scan_offset %lu numa_scan_seq %d\n"
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#endif
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"tlb_flush_pending %d\n"
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"def_flags: %#lx(%pGv)\n",
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mm, mm->mmap, (long long) mm->vmacache_seqnum, mm->task_size,
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#ifdef CONFIG_MMU
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mm->get_unmapped_area,
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#endif
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mm->mmap_base, mm->mmap_legacy_base, mm->highest_vm_end,
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mm->pgd, atomic_read(&mm->mm_users),
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atomic_read(&mm->mm_count),
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mm_pgtables_bytes(mm),
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mm->map_count,
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mm->hiwater_rss, mm->hiwater_vm, mm->total_vm, mm->locked_vm,
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mm->pinned_vm, mm->data_vm, mm->exec_vm, mm->stack_vm,
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mm->start_code, mm->end_code, mm->start_data, mm->end_data,
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mm->start_brk, mm->brk, mm->start_stack,
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mm->arg_start, mm->arg_end, mm->env_start, mm->env_end,
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mm->binfmt, mm->flags, mm->core_state,
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#ifdef CONFIG_AIO
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mm->ioctx_table,
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#endif
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#ifdef CONFIG_MEMCG
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mm->owner,
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#endif
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mm->exe_file,
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#ifdef CONFIG_MMU_NOTIFIER
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mm->mmu_notifier_mm,
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#endif
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#ifdef CONFIG_NUMA_BALANCING
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mm->numa_next_scan, mm->numa_scan_offset, mm->numa_scan_seq,
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#endif
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atomic_read(&mm->tlb_flush_pending),
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mm->def_flags, &mm->def_flags
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);
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}
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#endif /* CONFIG_DEBUG_VM */
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