}
EXPORT_SYMBOL(can_do_mlock);
-#ifdef CONFIG_UNEVICTABLE_LRU
/*
* Mlocked pages are marked with PageMlocked() flag for efficient testing
* in vmscan and, possibly, the fault path; and to support semi-accurate
}
}
-/*
- * called from munlock()/munmap() path with page supposedly on the LRU.
+/**
+ * munlock_vma_page - munlock a vma page
+ * @page - page to be unlocked
*
- * Note: unlike mlock_vma_page(), we can't just clear the PageMlocked
- * [in try_to_munlock()] and then attempt to isolate the page. We must
- * isolate the page to keep others from messing with its unevictable
- * and mlocked state while trying to munlock. However, we pre-clear the
- * mlocked state anyway as we might lose the isolation race and we might
- * not get another chance to clear PageMlocked. If we successfully
- * isolate the page and try_to_munlock() detects other VM_LOCKED vmas
- * mapping the page, it will restore the PageMlocked state, unless the page
- * is mapped in a non-linear vma. So, we go ahead and SetPageMlocked(),
- * perhaps redundantly.
- * If we lose the isolation race, and the page is mapped by other VM_LOCKED
- * vmas, we'll detect this in vmscan--via try_to_munlock() or try_to_unmap()
- * either of which will restore the PageMlocked state by calling
- * mlock_vma_page() above, if it can grab the vma's mmap sem.
+ * called from munlock()/munmap() path with page supposedly on the LRU.
+ * When we munlock a page, because the vma where we found the page is being
+ * munlock()ed or munmap()ed, we want to check whether other vmas hold the
+ * page locked so that we can leave it on the unevictable lru list and not
+ * bother vmscan with it. However, to walk the page's rmap list in
+ * try_to_munlock() we must isolate the page from the LRU. If some other
+ * task has removed the page from the LRU, we won't be able to do that.
+ * So we clear the PageMlocked as we might not get another chance. If we
+ * can't isolate the page, we leave it for putback_lru_page() and vmscan
+ * [page_referenced()/try_to_unmap()] to deal with.
*/
-static void munlock_vma_page(struct page *page)
+void munlock_vma_page(struct page *page)
{
BUG_ON(!PageLocked(page));
/*
* did try_to_unlock() succeed or punt?
*/
- if (ret == SWAP_SUCCESS || ret == SWAP_AGAIN)
+ if (ret != SWAP_MLOCK)
count_vm_event(UNEVICTABLE_PGMUNLOCKED);
putback_lru_page(page);
} else {
/*
- * We lost the race. let try_to_unmap() deal
- * with it. At least we get the page state and
- * mlock stats right. However, page is still on
- * the noreclaim list. We'll fix that up when
- * the page is eventually freed or we scan the
- * noreclaim list.
+ * Some other task has removed the page from the LRU.
+ * putback_lru_page() will take care of removing the
+ * page from the unevictable list, if necessary.
+ * vmscan [page_referenced()] will move the page back
+ * to the unevictable list if some other vma has it
+ * mlocked.
*/
if (PageUnevictable(page))
count_vm_event(UNEVICTABLE_PGSTRANDED);
}
/**
- * __mlock_vma_pages_range() - mlock/munlock a range of pages in the vma.
+ * __mlock_vma_pages_range() - mlock a range of pages in the vma.
* @vma: target vma
* @start: start address
* @end: end address
- * @mlock: 0 indicate munlock, otherwise mlock.
*
- * If @mlock == 0, unlock an mlocked range;
- * else mlock the range of pages. This takes care of making the pages present ,
- * too.
+ * This takes care of making the pages present too.
*
* return 0 on success, negative error code on error.
*
* vma->vm_mm->mmap_sem must be held for at least read.
*/
static long __mlock_vma_pages_range(struct vm_area_struct *vma,
- unsigned long start, unsigned long end,
- int mlock)
+ unsigned long start, unsigned long end)
{
struct mm_struct *mm = vma->vm_mm;
unsigned long addr = start;
struct page *pages[16]; /* 16 gives a reasonable batch */
int nr_pages = (end - start) / PAGE_SIZE;
int ret = 0;
- int gup_flags = 0;
+ int gup_flags;
VM_BUG_ON(start & ~PAGE_MASK);
VM_BUG_ON(end & ~PAGE_MASK);
VM_BUG_ON(start < vma->vm_start);
VM_BUG_ON(end > vma->vm_end);
- VM_BUG_ON((!rwsem_is_locked(&mm->mmap_sem)) &&
- (atomic_read(&mm->mm_users) != 0));
-
- /*
- * mlock: don't page populate if vma has PROT_NONE permission.
- * munlock: always do munlock although the vma has PROT_NONE
- * permission, or SIGKILL is pending.
- */
- if (!mlock)
- gup_flags |= GUP_FLAGS_IGNORE_VMA_PERMISSIONS |
- GUP_FLAGS_IGNORE_SIGKILL;
+ VM_BUG_ON(!rwsem_is_locked(&mm->mmap_sem));
+ gup_flags = FOLL_TOUCH | FOLL_GET;
if (vma->vm_flags & VM_WRITE)
- gup_flags |= GUP_FLAGS_WRITE;
+ gup_flags |= FOLL_WRITE;
while (nr_pages > 0) {
int i;
* This can happen for, e.g., VM_NONLINEAR regions before
* a page has been allocated and mapped at a given offset,
* or for addresses that map beyond end of a file.
- * We'll mlock the the pages if/when they get faulted in.
+ * We'll mlock the pages if/when they get faulted in.
*/
if (ret < 0)
break;
- if (ret == 0) {
- /*
- * We know the vma is there, so the only time
- * we cannot get a single page should be an
- * error (ret < 0) case.
- */
- WARN_ON(1);
- break;
- }
lru_add_drain(); /* push cached pages to LRU */
for (i = 0; i < ret; i++) {
struct page *page = pages[i];
- lock_page(page);
- /*
- * Because we lock page here and migration is blocked
- * by the elevated reference, we need only check for
- * page truncation (file-cache only).
- */
if (page->mapping) {
- if (mlock)
+ /*
+ * That preliminary check is mainly to avoid
+ * the pointless overhead of lock_page on the
+ * ZERO_PAGE: which might bounce very badly if
+ * there is contention. However, we're still
+ * dirtying its cacheline with get/put_page:
+ * we'll add another __get_user_pages flag to
+ * avoid it if that case turns out to matter.
+ */
+ lock_page(page);
+ /*
+ * Because we lock page here and migration is
+ * blocked by the elevated reference, we need
+ * only check for file-cache page truncation.
+ */
+ if (page->mapping)
mlock_vma_page(page);
- else
- munlock_vma_page(page);
+ unlock_page(page);
}
- unlock_page(page);
- put_page(page); /* ref from get_user_pages() */
-
- /*
- * here we assume that get_user_pages() has given us
- * a list of virtually contiguous pages.
- */
- addr += PAGE_SIZE; /* for next get_user_pages() */
- nr_pages--;
+ put_page(page); /* ref from get_user_pages() */
}
+
+ addr += ret * PAGE_SIZE;
+ nr_pages -= ret;
ret = 0;
}
- return ret; /* count entire vma as locked_vm */
+ return ret; /* 0 or negative error code */
}
/*
return retval;
}
-#else /* CONFIG_UNEVICTABLE_LRU */
-
-/*
- * Just make pages present if VM_LOCKED. No-op if unlocking.
- */
-static long __mlock_vma_pages_range(struct vm_area_struct *vma,
- unsigned long start, unsigned long end,
- int mlock)
-{
- if (mlock && (vma->vm_flags & VM_LOCKED))
- return make_pages_present(start, end);
- return 0;
-}
-
-static inline int __mlock_posix_error_return(long retval)
-{
- return 0;
-}
-
-#endif /* CONFIG_UNEVICTABLE_LRU */
-
/**
* mlock_vma_pages_range() - mlock pages in specified vma range.
* @vma - the vma containing the specfied address range
is_vm_hugetlb_page(vma) ||
vma == get_gate_vma(current))) {
- __mlock_vma_pages_range(vma, start, end, 1);
+ __mlock_vma_pages_range(vma, start, end);
/* Hide errors from mmap() and other callers */
return 0;
return nr_pages; /* error or pages NOT mlocked */
}
-
/*
* munlock_vma_pages_range() - munlock all pages in the vma range.'
* @vma - vma containing range to be munlock()ed.
* free them. This will result in freeing mlocked pages.
*/
void munlock_vma_pages_range(struct vm_area_struct *vma,
- unsigned long start, unsigned long end)
+ unsigned long start, unsigned long end)
{
+ unsigned long addr;
+
+ lru_add_drain();
vma->vm_flags &= ~VM_LOCKED;
- __mlock_vma_pages_range(vma, start, end, 0);
+
+ for (addr = start; addr < end; addr += PAGE_SIZE) {
+ struct page *page;
+ /*
+ * Although FOLL_DUMP is intended for get_dump_page(),
+ * it just so happens that its special treatment of the
+ * ZERO_PAGE (returning an error instead of doing get_page)
+ * suits munlock very well (and if somehow an abnormal page
+ * has sneaked into the range, we won't oops here: great).
+ */
+ page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP);
+ if (page && !IS_ERR(page)) {
+ lock_page(page);
+ /*
+ * Like in __mlock_vma_pages_range(),
+ * because we lock page here and migration is
+ * blocked by the elevated reference, we need
+ * only check for file-cache page truncation.
+ */
+ if (page->mapping)
+ munlock_vma_page(page);
+ unlock_page(page);
+ put_page(page);
+ }
+ cond_resched();
+ }
}
/*
* It's okay if try_to_unmap_one unmaps a page just after we
* set VM_LOCKED, __mlock_vma_pages_range will bring it back.
*/
- vma->vm_flags = newflags;
if (lock) {
- ret = __mlock_vma_pages_range(vma, start, end, 1);
-
- if (ret > 0) {
- mm->locked_vm -= ret;
- ret = 0;
- } else
- ret = __mlock_posix_error_return(ret); /* translate if needed */
+ vma->vm_flags = newflags;
+ ret = __mlock_vma_pages_range(vma, start, end);
+ if (ret < 0)
+ ret = __mlock_posix_error_return(ret);
} else {
- __mlock_vma_pages_range(vma, start, end, 0);
+ munlock_vma_pages_range(vma, start, end);
}
out:
free_uid(user);
}
-void *alloc_locked_buffer(size_t size)
+int account_locked_memory(struct mm_struct *mm, struct rlimit *rlim,
+ size_t size)
{
- unsigned long rlim, vm, pgsz;
- void *buffer = NULL;
+ unsigned long lim, vm, pgsz;
+ int error = -ENOMEM;
pgsz = PAGE_ALIGN(size) >> PAGE_SHIFT;
- down_write(¤t->mm->mmap_sem);
-
- rlim = current->signal->rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT;
- vm = current->mm->total_vm + pgsz;
- if (rlim < vm)
- goto out;
+ down_write(&mm->mmap_sem);
- rlim = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT;
- vm = current->mm->locked_vm + pgsz;
- if (rlim < vm)
+ lim = rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT;
+ vm = mm->total_vm + pgsz;
+ if (lim < vm)
goto out;
- buffer = kzalloc(size, GFP_KERNEL);
- if (!buffer)
+ lim = rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT;
+ vm = mm->locked_vm + pgsz;
+ if (lim < vm)
goto out;
- current->mm->total_vm += pgsz;
- current->mm->locked_vm += pgsz;
+ mm->total_vm += pgsz;
+ mm->locked_vm += pgsz;
+ error = 0;
out:
- up_write(¤t->mm->mmap_sem);
- return buffer;
+ up_write(&mm->mmap_sem);
+ return error;
}
-void refund_locked_buffer_memory(struct mm_struct *mm, size_t size)
+void refund_locked_memory(struct mm_struct *mm, size_t size)
{
unsigned long pgsz = PAGE_ALIGN(size) >> PAGE_SHIFT;
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff