Patch adds support for mapping file with MAP_HUGETLB and does
checks if filesystem supports huge page cache.
Signed-off-by: Radosław Smogura <mail@xxxxxxxxxx>
---
mm/mmap.c | 24 +++++++++++++++-
mm/shmem.c | 84 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 106 insertions(+), 2 deletions(-)
diff --git a/mm/mmap.c b/mm/mmap.c
index 3f758c7..19f3016 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -992,6 +992,12 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) |
mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
+ if (flags & MAP_HUGETLB) {
+ vm_flags &= ~VM_NOHUGEPAGE;
+ vm_flags |= VM_HUGEPAGE;
+ printk(KERN_INFO "Setted huge page mapping in do_mmap_pgoff.");
+ }
+
if (flags & MAP_LOCKED)
if (!can_do_mlock())
return -EPERM;
@@ -1086,11 +1092,25 @@ SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
if (!(flags & MAP_ANONYMOUS)) {
audit_mmap_fd(fd, flags);
- if (unlikely(flags & MAP_HUGETLB))
- return -EINVAL;
file = fget(fd);
if (!file)
goto out;
+
+ if (unlikely(flags & MAP_HUGETLB)) {
+#ifdef CONFIG_HUGEPAGECACHE
+ if (!(file->f_mapping->a_ops->defragpage)) {
+ fput(file);
+ retval = -EINVAL;
+ goto out;
+ } else {
+ printk(KERN_INFO "Called to mmap huge with"
+ " good fs type.\n");
+ }
+#else
+ fput(file);
+ return -EINVAL;
+#endif
+ }
} else if (flags & MAP_HUGETLB) {
struct user_struct *user = NULL;
/*
diff --git a/mm/shmem.c b/mm/shmem.c
index 269d049..a834488 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1065,6 +1065,90 @@ static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
return ret;
}
+static int shmem_fault_huge(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+ struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
+ int error;
+ int ret = VM_FAULT_LOCKED;
+
+ error = shmem_getpage(inode, vmf->pgoff, &vmf->page, SGP_CACHE, &ret);
+ if (error)
+ return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS);
+
+ /* Just portion of developer code, to force defragmentation, as we have
+ * no external interface to make defragmentation (or daemon to do it).
+ */
+ if ((vma->vm_flags & VM_HUGEPAGE) && !PageCompound(vmf->page)) {
+ /* Force defrag - mainly devo code */
+ int defragResult;
+ const loff_t hugeChunkSize = 1 << (PMD_SHIFT - PAGE_SHIFT);
+
+ const loff_t vmaSizeToMap = (vma->vm_start
+ + ((vmf->pgoff + vma->vm_pgoff + hugeChunkSize)
+ << PAGE_SHIFT) <= vma->vm_end) ?
+ hugeChunkSize : 0;
+
+ const loff_t inodeSizeToMap =
+ (vmf->pgoff + vma->vm_pgoff + hugeChunkSize <
+ inode->i_size) ? hugeChunkSize : 0;
+
+ const struct defrag_pagecache_ctl defragControl = {
+ .fillPages = 1,
+ .requireFillPages = 1,
+ .force = 1
+ };
+
+ if (ret & VM_FAULT_LOCKED) {
+ unlock_page(vmf->page);
+ }
+ put_page(vmf->page);
+
+ defragResult = defragPageCache(vma->vm_file,
+ vmf->pgoff,
+ min(vmaSizeToMap, min(inodeSizeToMap, hugeChunkSize)),
+ &defragControl);
+ printk(KERN_INFO "Page defragmented with result %d\n",
+ defragResult);
+
+ /* Retake page. */
+ error = shmem_getpage(inode, vmf->pgoff, &vmf->page, SGP_CACHE,
+ &ret);
+ if (error) {
+ return ((error == -ENOMEM) ?
+ VM_FAULT_OOM : VM_FAULT_SIGBUS);
+ }
+ }
+
+ /* XXX Page & compound lock ordering please... */
+
+ /* After standard fault page is getted. */
+ if (PageCompound(vmf->page)) {
+ compound_lock(vmf->page);
+ if (!PageHead(vmf->page)) {
+ compound_unlock(vmf->page);
+ goto no_hugepage;
+ }
+ }else {
+ goto no_hugepage;
+ }
+
+ if (!(ret & VM_FAULT_LOCKED))
+ lock_page(vmf->page);
+
+ ret |= VM_FAULT_LOCKED;
+
+ if (ret & VM_FAULT_MAJOR) {
+ count_vm_event(PGMAJFAULT);
+ mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT);
+ }
+ return ret;
+no_hugepage:
+ if (ret & VM_FAULT_LOCKED)
+ unlock_page(vmf->page);
+ page_cache_release(vmf->page);
+ vmf->page = NULL;
+ return VM_FAULT_NOHUGE;
+}
#ifdef CONFIG_NUMA
static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *mpol)
{
--
1.7.3.4
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