From: Yu Zhao <yuzhao@xxxxxxxxxx> POSIX_FADV_NOREUSE allows an application to specify that accesses to file data does not follow LRU and is used only once. Since 2.6.18 this is a no-op. We add FMODE_NOREUSE, checked in vma_has_locality to prevent LRU activation. Signed-off-by: Yu Zhao <yuzhao@xxxxxxxxxx> Signed-off-by: Yuanchu Xie <yuanchu@xxxxxxxxxx> --- include/linux/fs.h | 2 ++ include/linux/mm_inline.h | 3 +++ mm/fadvise.c | 5 ++++- 3 files changed, 9 insertions(+), 1 deletion(-) diff --git a/include/linux/fs.h b/include/linux/fs.h index 066555ad1bf8..5660ed0edf1a 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -166,6 +166,8 @@ typedef int (dio_iodone_t)(struct kiocb *iocb, loff_t offset, /* File supports DIRECT IO */ #define FMODE_CAN_ODIRECT ((__force fmode_t)0x400000) +#define FMODE_NOREUSE ((__force fmode_t)0x800000) + /* File was opened by fanotify and shouldn't generate fanotify events */ #define FMODE_NONOTIFY ((__force fmode_t)0x4000000) diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h index 80c0f6901ead..024f834d952d 100644 --- a/include/linux/mm_inline.h +++ b/include/linux/mm_inline.h @@ -583,6 +583,9 @@ static inline bool vma_has_locality(struct vm_area_struct *vma) if (vma->vm_flags & (VM_SEQ_READ | VM_RAND_READ)) return false; + if (vma->vm_file && (vma->vm_file->f_mode & FMODE_NOREUSE)) + return false; + return true; } diff --git a/mm/fadvise.c b/mm/fadvise.c index bf04fec87f35..fb7c5f43fd2a 100644 --- a/mm/fadvise.c +++ b/mm/fadvise.c @@ -80,7 +80,7 @@ int generic_fadvise(struct file *file, loff_t offset, loff_t len, int advice) case POSIX_FADV_NORMAL: file->f_ra.ra_pages = bdi->ra_pages; spin_lock(&file->f_lock); - file->f_mode &= ~FMODE_RANDOM; + file->f_mode &= ~(FMODE_RANDOM | FMODE_NOREUSE); spin_unlock(&file->f_lock); break; case POSIX_FADV_RANDOM: @@ -107,6 +107,9 @@ int generic_fadvise(struct file *file, loff_t offset, loff_t len, int advice) force_page_cache_readahead(mapping, file, start_index, nrpages); break; case POSIX_FADV_NOREUSE: + spin_lock(&file->f_lock); + file->f_mode |= FMODE_NOREUSE; + spin_unlock(&file->f_lock); break; case POSIX_FADV_DONTNEED: __filemap_fdatawrite_range(mapping, offset, endbyte, -- 2.39.0.314.g84b9a713c41-goog
