Re: [f2fs-dev] [PATCH v2] f2fs_io: adapt w/ page_size in aligned_xalloc()

[Chao Yu via Linux-f2fs-devel <linux-f2fs-devel@lists.sourceforge.net>]

On 6/17/26 15:33, Chao Yu wrote:
> When allocating memory in aligned_xalloc(), if the requested alignment
> (e.g., F2FS_DEFAULT_BLKSIZE) is smaller than the system's page size,
> aligned_alloc() will allocate memory that is not page-aligned on systems
> with 16KB or 64KB page sizes.
> 
> As a result, subsequent calls to madvise(..., MADV_HUGEPAGE) will fail
> because madvise() requires the memory address and length to be page-aligned.
> 
> Fix this by dynamically adjusting the alignment and rounding up the requested
> allocation size (via roundup()) to the system's page size, ensuring that
> memory is correctly page-aligned for madvise().

Minor thing:

Author info seems wrong, please help to correct, thanks.

author	Chao Yu via Linux-f2fs-devel <linux-f2fs-devel@lists.sourceforge.net>

https://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs-tools.git/commit/?h=dev-test&id=94525ec03cbdc3ead2e92c5e4ae229f9868317f2

Thanks,

> 
> Signed-off-by: Chao Yu <chao@kernel.org>
> ---
>   tools/f2fs_io/f2fs_io.c | 17 +++++++++++++++++
>   tools/f2fs_io/f2fs_io.h |  3 +++
>   2 files changed, 20 insertions(+)
> 
> diff --git a/tools/f2fs_io/f2fs_io.c b/tools/f2fs_io/f2fs_io.c
> index 94e61b8..9a866cc 100644
> --- a/tools/f2fs_io/f2fs_io.c
> +++ b/tools/f2fs_io/f2fs_io.c
> @@ -97,6 +97,23 @@ static void *xmalloc(size_t size)
>   
>   static void *aligned_xalloc(size_t alignment, size_t size)
>   {
> +	long page_size = F2FS_DEFAULT_BLKSIZE;
> +
> +#ifdef _SC_PAGESIZE
> +	page_size = sysconf(_SC_PAGESIZE);
> +	if (page_size < 0)
> +		page_size = F2FS_DEFAULT_BLKSIZE;
> +#endif
> +
> +	/*
> +	 * On systems with large page sizes (e.g., 16KB/64KB), alignment and
> +	 * allocation size must be page-aligned to satisfy madvise().
> +	 */
> +	if (alignment < (size_t)page_size)
> +		alignment = page_size;
> +
> +	size = roundup(size, alignment);
> +
>   	void *p = aligned_alloc(alignment, size);
>   
>   	if (!p)
> diff --git a/tools/f2fs_io/f2fs_io.h b/tools/f2fs_io/f2fs_io.h
> index 539964f..cf1c334 100644
> --- a/tools/f2fs_io/f2fs_io.h
> +++ b/tools/f2fs_io/f2fs_io.h
> @@ -49,6 +49,9 @@ typedef u32	__be32;
>   #endif
>   
>   #define F2FS_DEFAULT_BLKSIZE	4096
> +#ifndef roundup
> +#define roundup(x, y)		((((x) + ((y) - 1)) / (y)) * (y))
> +#endif
>   #define NEW_ADDR	0xFFFFFFFF
>   
>   #ifndef FS_IOC_GETFLAGS



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