Adding Damien to this thread. On 12/10/2019 10:17 PM, Chaitanya Kulkarni wrote: > Hi, > > * Background:- > ----------------------------------------------------------------------- > > Linux Kernel Block layer now supports new Zone Management operations > (REQ_OP_ZONE_[OPEN/CLOSE/FINISH] [1]). > > These operations are added mainly to support NVMe Zoned Namespces > (ZNS) [2]. We are adding support for ZNS in Linux Kernel Block layer, > user-space tools (sys-utils/nvme-cli), NVMe driver, File Systems, > Device-mapper in order to support these devices in the field. > > Over the years Linux kernel block layer tracing infrastructure > has proven to be not only extremely useful but essential for:- > > 1. Debugging the problems in the development of kernel block drivers. > 2. Solving the issues at the customer sites. > 3. Speeding up the development for the file system developers. > 4. Finding the device-related issues on the fly without modifying > the kernel. > 5. Building white box test-cases around the complex areas in the > linux-block layer. > > * Problem with block layer tracing infrastructure:- > ----------------------------------------------------------------------- > > If blktrace is such a great tool why we need this session for ? > > Existing blktrace infrastructure lacks the number of free bits that are > available to track the new trace category. With the addition of new > REQ_OP_ZONE_XXX we need more bits to expand the blktrace so that we can > track more number of requests. > > * Current state of the work:- > ----------------------------------------------------------------------- > > RFC implementations [3] has been posted with the addition of new IOCTLs > which is far from the production so that it can provide a basis to get > the discussion started. > > This RFC implementation provides:- > 1. Extended bits to track new trace categories. > 2. Support for tracing per trace priorities. > 3. Support for priority mask. > 4. New IOCTLs so that user-space tools can setup the extensions. > 5. Ability to track the integrity fields. > 6. blktrace and blkparse implementation which supports the above > mentioned features. > > Bart and Martin has suggested changes which I've incorporated in the RFC > revisions. > > * What we will discuss in the proposed session ? > ----------------------------------------------------------------------- > > I'd like to propose a session for Storage track to go over the following > discussion points:- > > 1. What is the right approach to move this work forward? > 2. What are the other information bits we need to add which will help > kernel community to speed up the development and improve tracing? > 3. What are the other tracepoints we need to add in the block layer > to improve the tracing? > 4. What are device driver callbacks tracing we can add in the block > layer? > 5. Since polling is becoming popular what are the new tracepoints > we need to improve debugging ? > > > * Required Participants:- > ----------------------------------------------------------------------- > > I'd like to invite block layer, device drivers and file system > developers to:- > > 1. Share their opinion on the topic. > 2. Share their experience and any other issues with blktrace > infrastructure. > 3. Uncover additional details that are missing from this proposal. > > Regards, > Chaitanya > > References :- > > [1] https://www.spinics.net/lists/linux-block/msg46043.html > [2] https://nvmexpress.org/new-nvmetm-specification-defines-zoned- > namespaces-zns-as-go-to-industry-technology/ > [3] https://www.spinics.net/lists/linux-btrace/msg01106.html > https://www.spinics.net/lists/linux-btrace/msg01002.html > https://www.spinics.net/lists/linux-btrace/msg01042.html > https://www.spinics.net/lists/linux-btrace/msg00880.html >
