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| author | Christoph Hellwig <hch@lst.de> | 2026-02-02 09:06:33 +0300 |
|---|---|---|
| committer | Eric Biggers <ebiggers@kernel.org> | 2026-02-03 04:15:26 +0300 |
| commit | f1a6cf44b344b1ac2cefb387779e3002be237a7e (patch) | |
| tree | d5a8639f50d557be2c241d6e7f227213b44cf301 /include/linux | |
| parent | 314b652b7e7ad335fa20b693c8878a4850dae098 (diff) | |
| download | linux-f1a6cf44b344b1ac2cefb387779e3002be237a7e.tar.xz | |
fsverity: kick off hash readahead at data I/O submission time
Currently all reads of the fsverity hashes are kicked off from the data
I/O completion handler, leading to needlessly dependent I/O. This is
worked around a bit by performing readahead on the level 0 nodes, but
still fairly ineffective.
Switch to a model where the ->read_folio and ->readahead methods instead
kick off explicit readahead of the fsverity hashed so they are usually
available at I/O completion time.
For 64k sequential reads on my test VM this improves read performance
from 2.4GB/s - 2.6GB/s to 3.5GB/s - 3.9GB/s. The improvements for
random reads are likely to be even bigger.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: David Sterba <dsterba@suse.com> # btrfs
Link: https://lore.kernel.org/r/20260202060754.270269-5-hch@lst.de
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/fsverity.h | 30 |
1 files changed, 22 insertions, 8 deletions
diff --git a/include/linux/fsverity.h b/include/linux/fsverity.h index 8ddaa87fece3..722a42754a86 100644 --- a/include/linux/fsverity.h +++ b/include/linux/fsverity.h @@ -97,10 +97,6 @@ struct fsverity_operations { * * @inode: the inode * @index: 0-based index of the page within the Merkle tree - * @num_ra_pages: The number of Merkle tree pages that should be - * prefetched starting at @index if the page at @index - * isn't already cached. Implementations may ignore this - * argument; it's only a performance optimization. * * This can be called at any time on an open verity file. It may be * called by multiple processes concurrently, even with the same page. @@ -110,8 +106,23 @@ struct fsverity_operations { * Return: the page on success, ERR_PTR() on failure */ struct page *(*read_merkle_tree_page)(struct inode *inode, - pgoff_t index, - unsigned long num_ra_pages); + pgoff_t index); + + /** + * Perform readahead of a Merkle tree for the given inode. + * + * @inode: the inode + * @index: 0-based index of the first page within the Merkle tree + * @nr_pages: number of pages to be read ahead. + * + * This can be called at any time on an open verity file. It may be + * called by multiple processes concurrently, even with the same range. + * + * Optional method so that ->read_merkle_tree_page preferably finds + * cached data instead of issuing dependent I/O. + */ + void (*readahead_merkle_tree)(struct inode *inode, pgoff_t index, + unsigned long nr_pages); /** * Write a Merkle tree block to the given file. @@ -308,8 +319,11 @@ static inline int fsverity_file_open(struct inode *inode, struct file *filp) } void fsverity_cleanup_inode(struct inode *inode); +void fsverity_readahead(struct inode *inode, pgoff_t index, + unsigned long nr_pages); -struct page *generic_read_merkle_tree_page(struct inode *inode, pgoff_t index, - unsigned long num_ra_pages); +struct page *generic_read_merkle_tree_page(struct inode *inode, pgoff_t index); +void generic_readahead_merkle_tree(struct inode *inode, pgoff_t index, + unsigned long nr_pages); #endif /* _LINUX_FSVERITY_H */ |