Re: [Linaro-mm-sig] [RFC/PATCH 3/5] mm: get_user_pages: use NON-MOVABLE pages when FOLL_DURABLE flag is set

Hi Marek,

It has been a long time since this patch-set was sent. And I'm pushing memory hot-remove works. I think I need your [patch3/5] to fix a problem I met.

We have sent a similar patch before. But I think yours may be better. :) https://lkml.org/lkml/2013/2/21/126

So would you please update and resend your patch again ? Or do you have your own plan to push it ?

Thanks. :)

On 03/05/2013 02:57 PM, Marek Szyprowski wrote:

Ensure that newly allocated pages, which are faulted in in FOLL_DURABLE mode comes from non-movalbe pageblocks, to workaround migration failures with Contiguous Memory Allocator.

Signed-off-by: Marek Szyprowskim.szyprowski@samsung.com Signed-off-by: Kyungmin Parkkyungmin.park@samsung.com

---

include/linux/highmem.h | 12 ++++++++++-- include/linux/mm.h | 2 ++ mm/memory.c | 24 ++++++++++++++++++------ 3 files changed, 30 insertions(+), 8 deletions(-)

diff --git a/include/linux/highmem.h b/include/linux/highmem.h index 7fb31da..cf0b9d8 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -168,7 +168,8 @@ __alloc_zeroed_user_highpage(gfp_t movableflags, #endif

/**

• • alloc_zeroed_user_highpage_movable - Allocate a zeroed HIGHMEM page for a VMA that the caller knows can move

• • alloc_zeroed_user_highpage_movable - Allocate a zeroed HIGHMEM page for

• • 			a VMA that the caller knows can move
    

  • @vma: The VMA the page is to be allocated for
  • @vaddr: The virtual address the page will be inserted into

@@ -177,11 +178,18 @@ __alloc_zeroed_user_highpage(gfp_t movableflags, */ static inline struct page * alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma,

• 			unsigned long vaddr)
  

• 		   unsigned long vaddr)
  

  { return __alloc_zeroed_user_highpage(__GFP_MOVABLE, vma, vaddr); }

+static inline struct page * +alloc_zeroed_user_highpage(gfp_t gfp, struct vm_area_struct *vma,

• 	   unsigned long vaddr)
  

+{

• return __alloc_zeroed_user_highpage(gfp, vma, vaddr);

+}

• static inline void clear_highpage(struct page *page) { void *kaddr = kmap_atomic(page);

diff --git a/include/linux/mm.h b/include/linux/mm.h index 9806e54..c11f58f 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -165,6 +165,7 @@ extern pgprot_t protection_map[16]; #define FAULT_FLAG_RETRY_NOWAIT 0x10 /* Don't drop mmap_sem and wait when retrying */ #define FAULT_FLAG_KILLABLE 0x20 /* The fault task is in SIGKILL killable region */ #define FAULT_FLAG_TRIED 0x40 /* second try */ +#define FAULT_FLAG_NO_CMA 0x80 /* don't use CMA pages */

/*

• vm_fault is filled by the the pagefault handler and passed to the vma's

@@ -1633,6 +1634,7 @@ static inline struct page *follow_page(struct vm_area_struct *vma, #define FOLL_HWPOISON 0x100 /* check page is hwpoisoned */ #define FOLL_NUMA 0x200 /* force NUMA hinting page fault */ #define FOLL_MIGRATION 0x400 /* wait for page to replace migration entry */ +#define FOLL_DURABLE 0x800 /* get the page reference for a long time */

typedef int (*pte_fn_t)(pte_t *pte, pgtable_t token, unsigned long addr, void *data); diff --git a/mm/memory.c b/mm/memory.c index 42dfd8e..2b9c2dd 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1816,6 +1816,9 @@ long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, int ret; unsigned int fault_flags = 0;

• 		if (gup_flags&  FOLL_DURABLE)
  

• 			fault_flags = FAULT_FLAG_NO_CMA;
  

• 	/* For mlock, just skip the stack guard page. */
  	if (foll_flags&  FOLL_MLOCK) {
  		if (stack_guard_page(vma, start))
  

@@ -2495,7 +2498,7 @@ static inline void cow_user_page(struct page *dst, struct page *src, unsigned lo */ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long address, pte_t *page_table, pmd_t *pmd,

• spinlock_t *ptl, pte_t orig_pte)
  

• spinlock_t *ptl, pte_t orig_pte, unsigned int flags)
  

  __releases(ptl) { struct page *old_page, *new_page = NULL;

@@ -2505,6 +2508,10 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, struct page *dirty_page = NULL; unsigned long mmun_start = 0; /* For mmu_notifiers */ unsigned long mmun_end = 0; /* For mmu_notifiers */

• gfp_t gfp = GFP_HIGHUSER_MOVABLE;

• if (IS_ENABLED(CONFIG_CMA)&& (flags& FAULT_FLAG_NO_CMA))

• gfp&= ~__GFP_MOVABLE;
  
  

  old_page = vm_normal_page(vma, address, orig_pte); if (!old_page) {

@@ -2668,11 +2675,11 @@ gotten: goto oom;

if (is_zero_pfn(pte_pfn(orig_pte))) {

• new_page = alloc_zeroed_user_highpage_movable(vma, address);
  

• new_page = alloc_zeroed_user_highpage(gfp, vma, address);
  

  if (!new_page) goto oom; } else {

• new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
  

• new_page = alloc_page_vma(gfp, vma, address);
  

  if (!new_page) goto oom; cow_user_page(new_page, old_page, address, vma);

@@ -3032,7 +3039,7 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma, }

if (flags& FAULT_FLAG_WRITE) {

• ret |= do_wp_page(mm, vma, address, page_table, pmd, ptl, pte);
  

• ret |= do_wp_page(mm, vma, address, page_table, pmd, ptl, pte, flags);
  

  if (ret& VM_FAULT_ERROR) ret&= VM_FAULT_ERROR; goto out;

@@ -3187,6 +3194,11 @@ static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma, struct vm_fault vmf; int ret; int page_mkwrite = 0;

• gfp_t gfp = GFP_HIGHUSER_MOVABLE;

• if (IS_ENABLED(CONFIG_CMA)&& (flags& FAULT_FLAG_NO_CMA))

• gfp&= ~__GFP_MOVABLE;
  

• /*

  • If we do COW later, allocate page befor taking lock_page()

@@ -3197,7 +3209,7 @@ static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma, if (unlikely(anon_vma_prepare(vma))) return VM_FAULT_OOM;

• cow_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
  

• cow_page = alloc_page_vma(gfp, vma, address);
  

  if (!cow_page) return VM_FAULT_OOM;

@@ -3614,7 +3626,7 @@ int handle_pte_fault(struct mm_struct *mm, if (flags& FAULT_FLAG_WRITE) { if (!pte_write(entry)) return do_wp_page(mm, vma, address,

• 			pte, pmd, ptl, entry);
  

• 			pte, pmd, ptl, entry, flags);
  

  entry = pte_mkdirty(entry); } entry = pte_mkyoung(entry);