mm: shmem: add mTHP size alignment in shmem_get_unmapped_area
Although the top-level hugepage allocation can be turned off, anonymous
shmem can still use mTHP by configuring the sysfs interface located at
'/sys/kernel/mm/transparent_hugepage/hugepage-XXkb/shmem_enabled'.
Therefore, add alignment for mTHP size to provide a suitable alignment
address in shmem_get_unmapped_area().
Link: https://lkml.kernel.org/r/0c549b57cf7db07503af692d8546ecfad0fcce52.1718090413.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Tested-by: Lance Yang <ioworker0@gmail.com>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Daniel Gomez <da.gomez@samsung.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
diff --git a/mm/shmem.c b/mm/shmem.c
index 8225b2f..224162a 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2393,6 +2393,7 @@ unsigned long shmem_get_unmapped_area(struct file *file,
unsigned long inflated_len;
unsigned long inflated_addr;
unsigned long inflated_offset;
+ unsigned long hpage_size;
if (len > TASK_SIZE)
return -ENOMEM;
@@ -2411,8 +2412,6 @@ unsigned long shmem_get_unmapped_area(struct file *file,
if (shmem_huge == SHMEM_HUGE_DENY)
return addr;
- if (len < HPAGE_PMD_SIZE)
- return addr;
if (flags & MAP_FIXED)
return addr;
/*
@@ -2424,8 +2423,11 @@ unsigned long shmem_get_unmapped_area(struct file *file,
if (uaddr == addr)
return addr;
+ hpage_size = HPAGE_PMD_SIZE;
if (shmem_huge != SHMEM_HUGE_FORCE) {
struct super_block *sb;
+ unsigned long __maybe_unused hpage_orders;
+ int order = 0;
if (file) {
VM_BUG_ON(file->f_op != &shmem_file_operations);
@@ -2438,18 +2440,38 @@ unsigned long shmem_get_unmapped_area(struct file *file,
if (IS_ERR(shm_mnt))
return addr;
sb = shm_mnt->mnt_sb;
+
+ /*
+ * Find the highest mTHP order used for anonymous shmem to
+ * provide a suitable alignment address.
+ */
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+ hpage_orders = READ_ONCE(huge_shmem_orders_always);
+ hpage_orders |= READ_ONCE(huge_shmem_orders_within_size);
+ hpage_orders |= READ_ONCE(huge_shmem_orders_madvise);
+ if (SHMEM_SB(sb)->huge != SHMEM_HUGE_NEVER)
+ hpage_orders |= READ_ONCE(huge_shmem_orders_inherit);
+
+ if (hpage_orders > 0) {
+ order = highest_order(hpage_orders);
+ hpage_size = PAGE_SIZE << order;
+ }
+#endif
}
- if (SHMEM_SB(sb)->huge == SHMEM_HUGE_NEVER)
+ if (SHMEM_SB(sb)->huge == SHMEM_HUGE_NEVER && !order)
return addr;
}
- offset = (pgoff << PAGE_SHIFT) & (HPAGE_PMD_SIZE-1);
- if (offset && offset + len < 2 * HPAGE_PMD_SIZE)
- return addr;
- if ((addr & (HPAGE_PMD_SIZE-1)) == offset)
+ if (len < hpage_size)
return addr;
- inflated_len = len + HPAGE_PMD_SIZE - PAGE_SIZE;
+ offset = (pgoff << PAGE_SHIFT) & (hpage_size - 1);
+ if (offset && offset + len < 2 * hpage_size)
+ return addr;
+ if ((addr & (hpage_size - 1)) == offset)
+ return addr;
+
+ inflated_len = len + hpage_size - PAGE_SIZE;
if (inflated_len > TASK_SIZE)
return addr;
if (inflated_len < len)
@@ -2462,10 +2484,10 @@ unsigned long shmem_get_unmapped_area(struct file *file,
if (inflated_addr & ~PAGE_MASK)
return addr;
- inflated_offset = inflated_addr & (HPAGE_PMD_SIZE-1);
+ inflated_offset = inflated_addr & (hpage_size - 1);
inflated_addr += offset - inflated_offset;
if (inflated_offset > offset)
- inflated_addr += HPAGE_PMD_SIZE;
+ inflated_addr += hpage_size;
if (inflated_addr > TASK_SIZE - len)
return addr;
