[LU-16033] refine ll_use_fast_io() for stride mode

• Type: Improvement
• Resolution: Unresolved
• Priority: Major
• Assignee: Zhenyu Xu
• Reporter: Zhenyu Xu

Description

ll_use_fast_io() calculates whether current readahead window covers next_readahead + max rpc pages, if that's the case, we can issue a readahed RPC, so we'd not do fast IO because we will need a cl_io to issue the RPC, otherwise we'd return true and do fast IO w/o issueing readahead RPC.

While for stride mode, the to-be-covered pages algorithm is

max_rpc_pages * (ras->ras_stride_length + ras->ras_stride_bytes - 1) / stride_bytes

which is not so accurate.

Comments

[Gerrit Updater]

"Bobi Jam <[e-mail]>" uploaded a new patch: https://review.whamcloud.com/48007
Subject: LU-16033 llite: refine ll_use_fast_io() for stride mode
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: 28bd9283ad4049c17cfdbb2d887f6bf522aac6cd