diff options
author | Zi Yan <zi.yan@cs.rutgers.edu> | 2017-09-08 16:11:01 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-09-08 18:26:45 -0700 |
commit | 84c3fc4e9c563d8fb91cfdf5948da48fe1af34d3 (patch) | |
tree | fc028524f9272c5ba1690d18937ebfc0bf0a0f9e /fs | |
parent | 616b8371539a6c487404c3b8fb04078016dab4ba (diff) |
mm: thp: check pmd migration entry in common path
When THP migration is being used, memory management code needs to handle
pmd migration entries properly. This patch uses !pmd_present() or
is_swap_pmd() (depending on whether pmd_none() needs separate code or
not) to check pmd migration entries at the places where a pmd entry is
present.
Since pmd-related code uses split_huge_page(), split_huge_pmd(),
pmd_trans_huge(), pmd_trans_unstable(), or
pmd_none_or_trans_huge_or_clear_bad(), this patch:
1. adds pmd migration entry split code in split_huge_pmd(),
2. takes care of pmd migration entries whenever pmd_trans_huge() is present,
3. makes pmd_none_or_trans_huge_or_clear_bad() pmd migration entry aware.
Since split_huge_page() uses split_huge_pmd() and pmd_trans_unstable()
is equivalent to pmd_none_or_trans_huge_or_clear_bad(), we do not change
them.
Until this commit, a pmd entry should be:
1. pointing to a pte page,
2. is_swap_pmd(),
3. pmd_trans_huge(),
4. pmd_devmap(), or
5. pmd_none().
Signed-off-by: Zi Yan <zi.yan@cs.rutgers.edu>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/proc/task_mmu.c | 32 |
1 files changed, 21 insertions, 11 deletions
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index a290966f91ec..8eec35af32e4 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -608,7 +608,8 @@ static int smaps_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, ptl = pmd_trans_huge_lock(pmd, vma); if (ptl) { - smaps_pmd_entry(pmd, addr, walk); + if (pmd_present(*pmd)) + smaps_pmd_entry(pmd, addr, walk); spin_unlock(ptl); return 0; } @@ -1012,6 +1013,9 @@ static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr, goto out; } + if (!pmd_present(*pmd)) + goto out; + page = pmd_page(*pmd); /* Clear accessed and referenced bits. */ @@ -1293,27 +1297,33 @@ static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end, if (ptl) { u64 flags = 0, frame = 0; pmd_t pmd = *pmdp; + struct page *page = NULL; if ((vma->vm_flags & VM_SOFTDIRTY) || pmd_soft_dirty(pmd)) flags |= PM_SOFT_DIRTY; - /* - * Currently pmd for thp is always present because thp - * can not be swapped-out, migrated, or HWPOISONed - * (split in such cases instead.) - * This if-check is just to prepare for future implementation. - */ if (pmd_present(pmd)) { - struct page *page = pmd_page(pmd); - - if (page_mapcount(page) == 1) - flags |= PM_MMAP_EXCLUSIVE; + page = pmd_page(pmd); flags |= PM_PRESENT; if (pm->show_pfn) frame = pmd_pfn(pmd) + ((addr & ~PMD_MASK) >> PAGE_SHIFT); } +#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION + else if (is_swap_pmd(pmd)) { + swp_entry_t entry = pmd_to_swp_entry(pmd); + + frame = swp_type(entry) | + (swp_offset(entry) << MAX_SWAPFILES_SHIFT); + flags |= PM_SWAP; + VM_BUG_ON(!is_pmd_migration_entry(pmd)); + page = migration_entry_to_page(entry); + } +#endif + + if (page && page_mapcount(page) == 1) + flags |= PM_MMAP_EXCLUSIVE; for (; addr != end; addr += PAGE_SIZE) { pagemap_entry_t pme = make_pme(frame, flags); |