Commit 5a9dd103 authored by Baolin Wang's avatar Baolin Wang Committed by Andrew Morton
Browse files

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: default avatarBaolin Wang <baolin.wang@linux.alibaba.com>
Tested-by: default avatarLance 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: default avatarAndrew Morton <akpm@linux-foundation.org>
parent e7a2ab7b

mm/shmem.c

+31 −9
Original line number Diff line number Diff line
@@ -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)

	if (len < hpage_size)

		return addr;



	offset = (pgoff << PAGE_SHIFT) & (hpage_size - 1);

	if (offset && offset + len < 2 * hpage_size)

		return addr;

	if ((addr & (HPAGE_PMD_SIZE-1)) == offset)

	if ((addr & (hpage_size - 1)) == offset)

		return addr;



	inflated_len = len + HPAGE_PMD_SIZE - PAGE_SIZE;

	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;