tree: https://git.kernel.org/pub/scm/linux/kernel/git/josef/btrfs-next.git blk-iolatency head: 657e770d4d6e3b03c3d4b96e427b30d6f766e2e2 commit: 90f955bbc57765617e3e99f784f3239c3d8f0360 [7/13] memcontrol: schedule throttling if we are congested config: x86_64-randconfig-x018-201820 (attached as .config) compiler: gcc-7 (Debian 7.3.0-16) 7.3.0 reproduce: git checkout 90f955bbc57765617e3e99f784f3239c3d8f0360 # save the attached .config to linux build tree make ARCH=x86_64
All warnings (new ones prefixed by >>):
In file included from include/linux/kernel.h:10:0,
from include/linux/list.h:9,
from include/linux/smp.h:12,
from include/linux/kernel_stat.h:5,
from mm/memory.c:41:
mm/memory.c: In function 'wp_page_copy':
mm/memory.c:2497:6: error: implicit declaration of function
'mem_cgroup_try_charge_delay'; did you mean 'mem_cgroup_try_charge_swap'?
[-Werror=implicit-function-declaration]
if (mem_cgroup_try_charge_delay(new_page, mm, GFP_KERNEL, &memcg, false))
^
include/linux/compiler.h:58:30: note: in definition of macro '__trace_if'
if (__builtin_constant_p(!!(cond)) ? !!(cond) : \
^~~~
>> mm/memory.c:2497:2: note: in expansion of macro 'if'
if (mem_cgroup_try_charge_delay(new_page, mm, GFP_KERNEL, &memcg, false))
^~
Cyclomatic Complexity 5 include/linux/compiler.h:__read_once_size
Cyclomatic Complexity 5 include/linux/compiler.h:__write_once_size
Cyclomatic Complexity 1 include/linux/kasan-checks.h:kasan_check_read
Cyclomatic Complexity 1 include/linux/kasan-checks.h:kasan_check_write
Cyclomatic Complexity 1 arch/x86/include/asm/bitops.h:__set_bit
Cyclomatic Complexity 3 arch/x86/include/asm/bitops.h:clear_bit
Cyclomatic Complexity 1 arch/x86/include/asm/bitops.h:test_and_set_bit
Cyclomatic Complexity 1 arch/x86/include/asm/bitops.h:test_and_set_bit_lock
Cyclomatic Complexity 1 arch/x86/include/asm/bitops.h:constant_test_bit
Cyclomatic Complexity 1 arch/x86/include/asm/bitops.h:variable_test_bit
Cyclomatic Complexity 1 arch/x86/include/asm/bitops.h:fls64
Cyclomatic Complexity 1 include/linux/bitops.h:fls_long
Cyclomatic Complexity 1 include/linux/log2.h:__rounddown_pow_of_two
Cyclomatic Complexity 2 include/linux/list.h:__list_add
Cyclomatic Complexity 1 include/linux/list.h:list_add
Cyclomatic Complexity 1 include/linux/list.h:list_empty
Cyclomatic Complexity 2 arch/x86/include/asm/jump_label.h:arch_static_branch
Cyclomatic Complexity 1 include/linux/jump_label.h:static_key_false
Cyclomatic Complexity 2 include/linux/string.h:kbasename
Cyclomatic Complexity 1 arch/x86/include/asm/atomic.h:arch_atomic_read
Cyclomatic Complexity 1 arch/x86/include/asm/atomic.h:arch_atomic_inc
Cyclomatic Complexity 1 arch/x86/include/asm/atomic.h:arch_atomic_dec
Cyclomatic Complexity 1
arch/x86/include/asm/atomic.h:arch_atomic_dec_and_test
Cyclomatic Complexity 1 arch/x86/include/asm/atomic64_64.h:arch_atomic64_read
Cyclomatic Complexity 1 arch/x86/include/asm/atomic64_64.h:arch_atomic64_add
Cyclomatic Complexity 1 arch/x86/include/asm/atomic64_64.h:arch_atomic64_sub
Cyclomatic Complexity 1 arch/x86/include/asm/atomic64_64.h:arch_atomic64_inc
Cyclomatic Complexity 1 arch/x86/include/asm/atomic64_64.h:arch_atomic64_dec
Cyclomatic Complexity 1 include/asm-generic/atomic-instrumented.h:atomic_read
Cyclomatic Complexity 1
include/asm-generic/atomic-instrumented.h:atomic64_read
Cyclomatic Complexity 1 include/asm-generic/atomic-instrumented.h:atomic_inc
Cyclomatic Complexity 1
include/asm-generic/atomic-instrumented.h:atomic64_inc
Cyclomatic Complexity 1 include/asm-generic/atomic-instrumented.h:atomic_dec
Cyclomatic Complexity 1
include/asm-generic/atomic-instrumented.h:atomic64_dec
Cyclomatic Complexity 1
include/asm-generic/atomic-instrumented.h:atomic64_add
Cyclomatic Complexity 1
include/asm-generic/atomic-instrumented.h:atomic64_sub
Cyclomatic Complexity 1
include/asm-generic/atomic-instrumented.h:atomic_dec_and_test
Cyclomatic Complexity 1 include/asm-generic/atomic-long.h:atomic_long_read
Cyclomatic Complexity 1 include/asm-generic/atomic-long.h:atomic_long_inc
Cyclomatic Complexity 1 include/asm-generic/atomic-long.h:atomic_long_dec
Cyclomatic Complexity 1 include/asm-generic/atomic-long.h:atomic_long_add
Cyclomatic Complexity 1 include/asm-generic/atomic-long.h:atomic_long_sub
Cyclomatic Complexity 1 include/linux/smp.h:up_smp_call_function
Cyclomatic Complexity 1 arch/x86/include/asm/current.h:get_current
Cyclomatic Complexity 2 arch/x86/include/asm/page_64.h:__phys_addr_nodebug
Cyclomatic Complexity 1 arch/x86/include/asm/page_64.h:clear_page
Cyclomatic Complexity 1 arch/x86/include/asm/page.h:copy_user_page
Cyclomatic Complexity 1 arch/x86/include/asm/pgtable_types.h:native_pgd_val
Cyclomatic Complexity 1 include/asm-generic/pgtable-nop4d.h:pgd_none
Cyclomatic Complexity 1 include/asm-generic/pgtable-nop4d.h:pgd_bad
Cyclomatic Complexity 1 include/asm-generic/pgtable-nop4d.h:pgd_clear
Cyclomatic Complexity 1 include/asm-generic/pgtable-nop4d.h:p4d_offset
Cyclomatic Complexity 1 arch/x86/include/asm/pgtable_types.h:native_p4d_val
Cyclomatic Complexity 1 arch/x86/include/asm/pgtable_types.h:native_pud_val
Cyclomatic Complexity 1 arch/x86/include/asm/pgtable_types.h:native_pmd_val
Cyclomatic Complexity 1 arch/x86/include/asm/pgtable_types.h:p4d_pfn_mask
Cyclomatic Complexity 1 arch/x86/include/asm/pgtable_types.h:p4d_flags_mask
Cyclomatic Complexity 1 arch/x86/include/asm/pgtable_types.h:p4d_flags
Cyclomatic Complexity 2 arch/x86/include/asm/pgtable_types.h:pud_pfn_mask
Cyclomatic Complexity 1 arch/x86/include/asm/pgtable_types.h:pud_flags_mask
Cyclomatic Complexity 1 arch/x86/include/asm/pgtable_types.h:pud_flags
Cyclomatic Complexity 2 arch/x86/include/asm/pgtable_types.h:pmd_pfn_mask
Cyclomatic Complexity 1 arch/x86/include/asm/pgtable_types.h:pmd_flags_mask
Cyclomatic Complexity 1 arch/x86/include/asm/pgtable_types.h:pmd_flags
Cyclomatic Complexity 1 arch/x86/include/asm/pgtable_types.h:native_make_pte
Cyclomatic Complexity 1 arch/x86/include/asm/pgtable_types.h:native_pte_val
Cyclomatic Complexity 1 arch/x86/include/asm/pgtable_types.h:pte_flags
Cyclomatic Complexity 1 arch/x86/include/asm/paravirt.h:paravirt_alloc_pte
Cyclomatic Complexity 1 arch/x86/include/asm/paravirt.h:paravirt_alloc_pmd
Cyclomatic Complexity 1 arch/x86/include/asm/paravirt.h:paravirt_alloc_pud
Cyclomatic Complexity 1 arch/x86/include/asm/paravirt.h:__pte
Cyclomatic Complexity 1 arch/x86/include/asm/paravirt.h:pte_val
Cyclomatic Complexity 1 arch/x86/include/asm/paravirt.h:__pgd
Cyclomatic Complexity 1 arch/x86/include/asm/paravirt.h:pgd_val
Cyclomatic Complexity 1
arch/x86/include/asm/paravirt.h:ptep_modify_prot_start
Cyclomatic Complexity 1
arch/x86/include/asm/paravirt.h:ptep_modify_prot_commit
Cyclomatic Complexity 1 arch/x86/include/asm/paravirt.h:set_pte_at
Cyclomatic Complexity 1 arch/x86/include/asm/paravirt.h:set_pmd
Cyclomatic Complexity 1 arch/x86/include/asm/paravirt.h:__pmd
Cyclomatic Complexity 1 arch/x86/include/asm/paravirt.h:pmd_val
Cyclomatic Complexity 1 arch/x86/include/asm/paravirt.h:set_pud
Cyclomatic Complexity 1 arch/x86/include/asm/paravirt.h:__pud
Cyclomatic Complexity 1 arch/x86/include/asm/paravirt.h:pud_val
Cyclomatic Complexity 1 arch/x86/include/asm/paravirt.h:pud_clear
Cyclomatic Complexity 1 arch/x86/include/asm/paravirt.h:set_p4d
Cyclomatic Complexity 1 arch/x86/include/asm/paravirt.h:p4d_clear
Cyclomatic Complexity 1 arch/x86/include/asm/paravirt.h:pte_clear
Cyclomatic Complexity 1 arch/x86/include/asm/paravirt.h:pmd_clear
Cyclomatic Complexity 1
arch/x86/include/asm/paravirt.h:arch_enter_lazy_mmu_mode
Cyclomatic Complexity 1
arch/x86/include/asm/paravirt.h:arch_leave_lazy_mmu_mode
Cyclomatic Complexity 1 arch/x86/include/asm/special_insns.h:__read_pkru
Cyclomatic Complexity 1 include/linux/err.h:IS_ERR
Cyclomatic Complexity 2 include/linux/thread_info.h:test_ti_thread_flag
Cyclomatic Complexity 1 include/linux/thread_info.h:check_object_size
Cyclomatic Complexity 1 arch/x86/include/asm/preempt.h:should_resched
Cyclomatic Complexity 1 include/linux/spinlock.h:spinlock_check
Cyclomatic Complexity 1 include/linux/spinlock.h:spin_lock
Cyclomatic Complexity 1 include/linux/spinlock.h:spin_unlock
vim +/if +2497 mm/memory.c
2452
2453 /*
2454 * Handle the case of a page which we actually need to copy to a new
page.
2455 *
2456 * Called with mmap_sem locked and the old page referenced, but
2457 * without the ptl held.
2458 *
2459 * High level logic flow:
2460 *
2461 * - Allocate a page, copy the content of the old page to the new one.
2462 * - Handle book keeping and accounting - cgroups, mmu-notifiers, etc.
2463 * - Take the PTL. If the pte changed, bail out and release the
allocated page
2464 * - If the pte is still the way we remember it, update the page table
and all
2465 * relevant references. This includes dropping the reference the
page-table
2466 * held to the old page, as well as updating the rmap.
2467 * - In any case, unlock the PTL and drop the reference we took to the
old page.
2468 */
2469 static int wp_page_copy(struct vm_fault *vmf)
2470 {
2471 struct vm_area_struct *vma = vmf->vma;
2472 struct mm_struct *mm = vma->vm_mm;
2473 struct page *old_page = vmf->page;
2474 struct page *new_page = NULL;
2475 pte_t entry;
2476 int page_copied = 0;
2477 const unsigned long mmun_start = vmf->address & PAGE_MASK;
2478 const unsigned long mmun_end = mmun_start + PAGE_SIZE;
2479 struct mem_cgroup *memcg;
2480
2481 if (unlikely(anon_vma_prepare(vma)))
2482 goto oom;
2483
2484 if (is_zero_pfn(pte_pfn(vmf->orig_pte))) {
2485 new_page = alloc_zeroed_user_highpage_movable(vma,
2486
vmf->address);
2487 if (!new_page)
2488 goto oom;
2489 } else {
2490 new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma,
2491 vmf->address);
2492 if (!new_page)
2493 goto oom;
2494 cow_user_page(new_page, old_page, vmf->address, vma);
2495 }
2496
> 2497 if (mem_cgroup_try_charge_delay(new_page, mm, GFP_KERNEL,
> &memcg, false))
2498 goto oom_free_new;
2499
2500 __SetPageUptodate(new_page);
2501
2502 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
2503
2504 /*
2505 * Re-check the pte - we dropped the lock
2506 */
2507 vmf->pte = pte_offset_map_lock(mm, vmf->pmd, vmf->address,
&vmf->ptl);
2508 if (likely(pte_same(*vmf->pte, vmf->orig_pte))) {
2509 if (old_page) {
2510 if (!PageAnon(old_page)) {
2511 dec_mm_counter_fast(mm,
2512
mm_counter_file(old_page));
2513 inc_mm_counter_fast(mm, MM_ANONPAGES);
2514 }
2515 } else {
2516 inc_mm_counter_fast(mm, MM_ANONPAGES);
2517 }
2518 flush_cache_page(vma, vmf->address,
pte_pfn(vmf->orig_pte));
2519 entry = mk_pte(new_page, vma->vm_page_prot);
2520 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2521 /*
2522 * Clear the pte entry and flush it first, before
updating the
2523 * pte with the new entry. This will avoid a race
condition
2524 * seen in the presence of one thread doing SMC and
another
2525 * thread doing COW.
2526 */
2527 ptep_clear_flush_notify(vma, vmf->address, vmf->pte);
2528 page_add_new_anon_rmap(new_page, vma, vmf->address,
false);
2529 mem_cgroup_commit_charge(new_page, memcg, false, false);
2530 lru_cache_add_active_or_unevictable(new_page, vma);
2531 /*
2532 * We call the notify macro here because, when using
secondary
2533 * mmu page tables (such as kvm shadow page tables), we
want the
2534 * new page to be mapped directly into the secondary
page table.
2535 */
2536 set_pte_at_notify(mm, vmf->address, vmf->pte, entry);
2537 update_mmu_cache(vma, vmf->address, vmf->pte);
2538 if (old_page) {
2539 /*
2540 * Only after switching the pte to the new page
may
2541 * we remove the mapcount here. Otherwise
another
2542 * process may come and find the rmap count
decremented
2543 * before the pte is switched to the new page,
and
2544 * "reuse" the old page writing into it while
our pte
2545 * here still points into it and can be read by
other
2546 * threads.
2547 *
2548 * The critical issue is to order this
2549 * page_remove_rmap with the ptp_clear_flush
above.
2550 * Those stores are ordered by (if nothing
else,)
2551 * the barrier present in the
atomic_add_negative
2552 * in page_remove_rmap.
2553 *
2554 * Then the TLB flush in ptep_clear_flush
ensures that
2555 * no process can access the old page before the
2556 * decremented mapcount is visible. And the old
page
2557 * cannot be reused until after the decremented
2558 * mapcount is visible. So transitively, TLBs to
2559 * old page will be flushed before it can be
reused.
2560 */
2561 page_remove_rmap(old_page, false);
2562 }
2563
2564 /* Free the old page.. */
2565 new_page = old_page;
2566 page_copied = 1;
2567 } else {
2568 mem_cgroup_cancel_charge(new_page, memcg, false);
2569 }
2570
2571 if (new_page)
2572 put_page(new_page);
2573
2574 pte_unmap_unlock(vmf->pte, vmf->ptl);
2575 /*
2576 * No need to double call mmu_notifier->invalidate_range()
callback as
2577 * the above ptep_clear_flush_notify() did already call it.
2578 */
2579 mmu_notifier_invalidate_range_only_end(mm, mmun_start,
mmun_end);
2580 if (old_page) {
2581 /*
2582 * Don't let another task, with possibly unlocked vma,
2583 * keep the mlocked page.
2584 */
2585 if (page_copied && (vma->vm_flags & VM_LOCKED)) {
2586 lock_page(old_page); /* LRU manipulation */
2587 if (PageMlocked(old_page))
2588 munlock_vma_page(old_page);
2589 unlock_page(old_page);
2590 }
2591 put_page(old_page);
2592 }
2593 return page_copied ? VM_FAULT_WRITE : 0;
2594 oom_free_new:
2595 put_page(new_page);
2596 oom:
2597 if (old_page)
2598 put_page(old_page);
2599 return VM_FAULT_OOM;
2600 }
2601
---
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