diff options
Diffstat (limited to 'mm/hugetlb.c')
| -rw-r--r-- | mm/hugetlb.c | 72 |
1 files changed, 48 insertions, 24 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 4a1d7021efaf..cd3fc4194733 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -245,11 +245,15 @@ struct file_region { * expanded, because region_add is only called after region_chg * with the same range. If a new file_region structure must * be allocated, it is done in region_chg. + * + * Return the number of new huge pages added to the map. This + * number is greater than or equal to zero. */ static long region_add(struct resv_map *resv, long f, long t) { struct list_head *head = &resv->regions; struct file_region *rg, *nrg, *trg; + long add = 0; spin_lock(&resv->lock); /* Locate the region we are either in or before. */ @@ -275,14 +279,24 @@ static long region_add(struct resv_map *resv, long f, long t) if (rg->to > t) t = rg->to; if (rg != nrg) { + /* Decrement return value by the deleted range. + * Another range will span this area so that by + * end of routine add will be >= zero + */ + add -= (rg->to - rg->from); list_del(&rg->link); kfree(rg); } } + + add += (nrg->from - f); /* Added to beginning of region */ nrg->from = f; + add += t - nrg->to; /* Added to end of region */ nrg->to = t; + spin_unlock(&resv->lock); - return 0; + VM_BUG_ON(add < 0); + return add; } /* @@ -1470,46 +1484,56 @@ static void return_unused_surplus_pages(struct hstate *h, } /* - * Determine if the huge page at addr within the vma has an associated - * reservation. Where it does not we will need to logically increase - * reservation and actually increase subpool usage before an allocation - * can occur. Where any new reservation would be required the - * reservation change is prepared, but not committed. Once the page - * has been allocated from the subpool and instantiated the change should - * be committed via vma_commit_reservation. No action is required on - * failure. + * vma_needs_reservation and vma_commit_reservation are used by the huge + * page allocation routines to manage reservations. + * + * vma_needs_reservation is called to determine if the huge page at addr + * within the vma has an associated reservation. If a reservation is + * needed, the value 1 is returned. The caller is then responsible for + * managing the global reservation and subpool usage counts. After + * the huge page has been allocated, vma_commit_reservation is called + * to add the page to the reservation map. + * + * In the normal case, vma_commit_reservation returns the same value + * as the preceding vma_needs_reservation call. The only time this + * is not the case is if a reserve map was changed between calls. It + * is the responsibility of the caller to notice the difference and + * take appropriate action. */ -static long vma_needs_reservation(struct hstate *h, - struct vm_area_struct *vma, unsigned long addr) +static long __vma_reservation_common(struct hstate *h, + struct vm_area_struct *vma, unsigned long addr, + bool commit) { struct resv_map *resv; pgoff_t idx; - long chg; + long ret; resv = vma_resv_map(vma); if (!resv) return 1; idx = vma_hugecache_offset(h, vma, addr); - chg = region_chg(resv, idx, idx + 1); + if (commit) + ret = region_add(resv, idx, idx + 1); + else + ret = region_chg(resv, idx, idx + 1); if (vma->vm_flags & VM_MAYSHARE) - return chg; + return ret; else - return chg < 0 ? chg : 0; + return ret < 0 ? ret : 0; } -static void vma_commit_reservation(struct hstate *h, + +static long vma_needs_reservation(struct hstate *h, struct vm_area_struct *vma, unsigned long addr) { - struct resv_map *resv; - pgoff_t idx; - - resv = vma_resv_map(vma); - if (!resv) - return; + return __vma_reservation_common(h, vma, addr, false); +} - idx = vma_hugecache_offset(h, vma, addr); - region_add(resv, idx, idx + 1); +static long vma_commit_reservation(struct hstate *h, + struct vm_area_struct *vma, unsigned long addr) +{ + return __vma_reservation_common(h, vma, addr, true); } static struct page *alloc_huge_page(struct vm_area_struct *vma, |