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c004a6fe0c
The PV block protocol is using 4KB page granularity. The goal of this patch is to allow a Linux using 64KB page granularity using block device on a non-modified Xen. The block API is using segment which should at least be the size of a Linux page. Therefore, the driver will have to break the page in chunk of 4K before giving the page to the backend. When breaking a 64KB segment in 4KB chunks, it is possible that some chunks are empty. As the PV protocol always require to have data in the chunk, we have to count the number of Xen page which will be in use and avoid sending empty chunks. Note that, a pre-defined number of grants are reserved before preparing the request. This pre-defined number is based on the number and the maximum size of the segments. If each segment contains a very small amount of data, the driver may reserve too many grants (16 grants is reserved per segment with 64KB page granularity). Furthermore, in the case of persistent grants we allocate one Linux page per grant although only the first 4KB of the page will be effectively in use. This could be improved by sharing the page with multiple grants. Signed-off-by: Julien Grall <julien.grall@citrix.com> Acked-by: Roger Pau Monné <roger.pau@citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com> |
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| .. | ||
| aoe | ||
| drbd | ||
| mtip32xx | ||
| paride | ||
| rsxx | ||
| xen-blkback | ||
| zram | ||
| amiflop.c | ||
| ataflop.c | ||
| brd.c | ||
| cciss.c | ||
| cciss.h | ||
| cciss_cmd.h | ||
| cciss_scsi.c | ||
| cciss_scsi.h | ||
| cpqarray.c | ||
| cpqarray.h | ||
| cryptoloop.c | ||
| DAC960.c | ||
| DAC960.h | ||
| floppy.c | ||
| hd.c | ||
| ida_cmd.h | ||
| ida_ioctl.h | ||
| Kconfig | ||
| loop.c | ||
| loop.h | ||
| Makefile | ||
| mg_disk.c | ||
| nbd.c | ||
| null_blk.c | ||
| nvme-core.c | ||
| nvme-scsi.c | ||
| osdblk.c | ||
| pktcdvd.c | ||
| ps3disk.c | ||
| ps3vram.c | ||
| rbd.c | ||
| rbd_types.h | ||
| skd_main.c | ||
| skd_s1120.h | ||
| smart1,2.h | ||
| sunvdc.c | ||
| swim.c | ||
| swim3.c | ||
| swim_asm.S | ||
| sx8.c | ||
| umem.c | ||
| umem.h | ||
| virtio_blk.c | ||
| xen-blkfront.c | ||
| xsysace.c | ||
| z2ram.c | ||