From 5a9dd10380a16b343aa87d80d5bcc24409a03f5b Mon Sep 17 00:00:00 2001 From: Baolin Wang Date: Tue, 11 Jun 2024 18:11:09 +0800 Subject: [PATCH] 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 Tested-by: Lance Yang Cc: Barry Song Cc: Daniel Gomez Cc: David Hildenbrand Cc: "Huang, Ying" Cc: Hugh Dickins Cc: Kefeng Wang Cc: Pankaj Raghav Cc: Ryan Roberts Cc: Yang Shi Cc: Zi Yan Signed-off-by: Andrew Morton --- mm/shmem.c | 42 ++++++++++++++++++++++++++++++++---------- 1 file changed, 32 insertions(+), 10 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index 8225b2f230eb..224162aa204b 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;