On 9/7/2020 10:29 AM, Christoph Hellwig wrote:
On Thu, Sep 03, 2020 at 06:54:34PM +0300, Leon Romanovsky wrote:From: Maor Gottlieb <maorg@xxxxxxxxxx> Currently, sg_alloc_table_from_pages doesn't support dynamic chaining of SG entries. Therefore it requires from user to allocate all the pages in advance and hold them in a large buffer. Such a buffer consumes a lot of temporary memory in HPC systems which do a very large memory registration. The next patches introduce API for dynamically allocation from pages and it requires us to do the following: * Extract the code to alloc_from_pages_common. * Change the build of the table to iterate on the chunks and not on the SGEs. It will allow dynamic allocation of more SGEs. Since sg_alloc_table_from_pages allocate exactly the number of chunks, therefore chunks are equal to the number of SG entries.Given how few users __sg_alloc_table_from_pages has, what about just switching it to your desired calling conventions without another helper?
I tried it now. It didn't save a lot. Please give me your decision and if needed I will update accordingly.
