LU-14599 osp: limit allocation at osp_sync_process_committed

LU-14599 osp: limit allocation at osp_sync_process_committed

Sometimes osp cancels very large cookie list with 64K elements.
In this case osp_sync_process_committed() tries to allocate 64 pages
and uses vmalloc.
The fix limits memory allocation size to 4 page with kmalloc, and
reuse it in a loop.

HPE-bug-id: LUS-9815
Fixes: 6d7332102 ("LU-11924 osp: combine llog cancel operations")
Signed-off-by: Alexander Boyko <alexander.boyko@hpe.com>
Change-Id: Ic875335a28f78494fdb3cbc4b0145e5a43831ee8
Reviewed-on: https://review.whamcloud.com/43250
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Andrew Perepechko <andrew.perepechko@hpe.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>