Commit-ID: 9d6800cb12d36964a6fd4e68da06cd0c5c8d1ca0 Gitweb: http://git.kernel.org/tip/9d6800cb12d36964a6fd4e68da06cd0c5c8d1ca0 Author: Ingo Molnar <[email protected]> AuthorDate: Sat, 20 Oct 2012 23:06:00 +0200 Committer: Ingo Molnar <[email protected]> CommitDate: Tue, 23 Oct 2012 11:53:53 +0200
numa, mm, sched: Use down_write() in task_numa_work() change_protection() needs to be called with the mmap_sem write-locked, like the mprotect() variants do it. With that in place we can avoid the intrusive (and partially incorrect) page locking changes in the: "numa, mm: Fix 4K migration races" patch, because the down_write() will properly serialize with the down_read() page fault path. Keep the cleanups and debug code removal. In theory calling change_protection() with just down_read() should work, but in practice it seems messy. Signed-off-by: Ingo Molnar <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Andrea Arcangeli <[email protected]> Cc: Rik van Riel <[email protected]> Link: http://lkml.kernel.org/n/[email protected] --- kernel/sched/fair.c | 4 ++-- mm/huge_memory.c | 6 ------ mm/memory.c | 12 +++++++----- 3 files changed, 9 insertions(+), 13 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 9f7406e..f8b3539 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -937,7 +937,7 @@ void task_numa_work(struct callback_head *work) length = sysctl_sched_numa_scan_size; length <<= 20; - down_read(&mm->mmap_sem); + down_write(&mm->mmap_sem); vma = find_vma(mm, offset); again: if (!vma) { @@ -964,7 +964,7 @@ again: goto again; } mm->numa_scan_offset = offset; - up_read(&mm->mmap_sem); + up_write(&mm->mmap_sem); } diff --git a/mm/huge_memory.c b/mm/huge_memory.c index bcba184..4767200 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -781,10 +781,6 @@ unlock: return; migrate: - WARN_ON(!(((unsigned long)page->mapping & PAGE_MAPPING_ANON))); - WARN_ON((((unsigned long)page->mapping & PAGE_MAPPING_KSM))); - BUG_ON(PageSwapCache(page)); - spin_unlock(&mm->page_table_lock); lock_page(page); @@ -801,8 +797,6 @@ migrate: (GFP_TRANSHUGE | GFP_THISNODE) & ~__GFP_WAIT, HPAGE_PMD_ORDER); - WARN_ON(PageLRU(new_page)); - if (!new_page) goto alloc_fail; diff --git a/mm/memory.c b/mm/memory.c index 7ff1905..2c17d82 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3489,7 +3489,7 @@ static int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, ptl = pte_lockptr(mm, pmd); spin_lock(ptl); if (unlikely(!pte_same(*ptep, entry))) - goto unlock; + goto out_unlock; page = vm_normal_page(vma, address, entry); if (page) { @@ -3500,16 +3500,18 @@ static int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, goto migrate; } -fixup: +out_pte_upgrade_unlock: flush_cache_page(vma, address, pte_pfn(entry)); ptep_modify_prot_start(mm, address, ptep); entry = pte_modify(entry, vma->vm_page_prot); ptep_modify_prot_commit(mm, address, ptep, entry); + /* No TLB flush needed because we upgraded the PTE */ + update_mmu_cache(vma, address, ptep); -unlock: +out_unlock: pte_unmap_unlock(ptep, ptl); out: if (page) { @@ -3531,10 +3533,10 @@ migrate: if (!pte_same(*ptep, entry)) { put_page(page); page = NULL; - goto unlock; + goto out_unlock; } - goto fixup; + goto out_pte_upgrade_unlock; } /* -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
