mm/zswap: reuse dstmem when decompress

Patch series "mm/zswap: dstmem reuse optimizations and cleanups", v5.

The problem this series tries to optimize is that zswap_load() and
zswap_writeback_entry() have to malloc a temporary memory to support
!zpool_can_sleep_mapped().  We can avoid it by reusing the percpu
crypto_acomp_ctx->dstmem, which is also used by zswap_store() and
protected by the same percpu crypto_acomp_ctx->mutex.


This patch (of 5):

In the !zpool_can_sleep_mapped() case such as zsmalloc, we need to first
copy the entry->handle memory to a temporary memory, which is allocated
using kmalloc.

Obviously we can reuse the per-compressor dstmem to avoid allocating every
time, since it's percpu-compressor and protected in percpu mutex.

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Chengming Zhou <[email protected]>
Reviewed-by: Nhat Pham <[email protected]>
Reviewed-by: Yosry Ahmed <[email protected]>
Acked-by: Chris Li <[email protected]> (Google)
Cc: Barry Song <[email protected]>
Cc: Dan Streetman <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Seth Jennings <[email protected]>
Cc: Vitaly Wool <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions