On Sat, 14 Mar 2026 at 20:25, Eric Biggers <[email protected]> wrote: > > On Thu, Mar 12, 2026 at 07:29:05PM -0400, Mimi Zohar wrote: > > On Wed, 2026-03-11 at 22:39 -0700, Eric Biggers wrote: > > > IMA computes hashes using the crypto_shash or crypto_ahash API. The > > > latter is used only when ima.ahash_minsize is set on the command line, > > > and its purpose is ostensibly to make the hash computation faster. > > > > > > However, going off the CPU to a crypto engine and back again is actually > > > quite slow, especially compared with the acceleration that is built into > > > modern CPUs and the kernel now enables by default for most algorithms. > > > Typical performance results for SHA-256 on a modern platform can be > > > found at https://lore.kernel.org/linux-crypto/20250615184638.GA1480@sol/ > > > > > > Partly for this reason, several other kernel subsystems have already > > > dropped support for the crypto_ahash API. > > > > The performance benefit was the ability of reading and filling a buffer from > > disk, which was slow, while the other buffer was sent to the crypto engine. > > On normal filesystems, sequential reads from a file already kick off > async readahead. So the hashing and disk reads can already happen > concurrently anyway. > > - Eric
I think this is fine. It was developed to be used on OMAP processors a long time ago. It can go away.. Ack
