[LU-794] allow larger O_DIRECT requests with large allocations

• Type: Improvement
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.2.0
• Assignee: Andreas Dilger
• Reporter: Andreas Dilger

Description

In ll_direct_IO_26() it implements a MAX_DIO_SIZE limit for O_DIRECT requests, based on the previous 128kB kmalloc() limit. However, the underlying code was changed to use OBD_ALLOC_LARGE() and can handle arbitrarily large allocations with vmalloc. Increase the limit from 22MB (128kB kmalloc limit) to 512MB (actually 682MB, just below 4MB new kmalloc limit, and arbitrary with vmalloc).

Issue Links

• Trackbacks: Changelog 2.2 version 2.2.0 Support for networks: o2iblnd OFED 1.5.4 Server support for kernels: 2.6.32220.4.2.el6 (RHEL6) Client support for unpatched kernels: 2.6.18274.18.1.el5 (RHEL5) 2.6.32220.4.2.el6 (RHEL6) 2.6.32.360....