On 11/5/20 4:38 PM, Douglas Gilbert wrote: > A long time ago this driver's store was allocated by kmalloc() or > alloc_pages(). When this was switched to vmalloc() the author > noticed slower ramdisk access times and more variability in repeated > tests. So try going back with sgl_alloc_order() to get uniformly > sized allocations in a sometimes large scatter gather _array_. That > array is the basis of keeping O(1) access to the store. > > Using sgl_alloc_order() and friends requires CONFIG_SGL_ALLOC > so add a 'select' to the Kconfig file. > > Remove kcalloc() in resp_verify() as sgl_s can now be compared > directly without forming an intermediate buffer. This is a > performance win for the SCSI VERIFY command implementation. > > Make the SCSI COMPARE AND WRITE command yield the offset of the > first miscompared byte when the compare fails (as required by > T10). > > This patch depends on: "[PATCH v4 0/4] scatterlist: add new > capabilities". Hi Doug, Although I'm fine with this patch: has it been considered to use huge pages instead of allocating a scatterlist? Would that have the same or even better performance advantages? Thanks, Bart.
