On Wed, 24 Jan 2024 at 15:16, Breno Leitao <leitao@xxxxxxxxxx> wrote: > > Hello Andrey, > > On Mon, Nov 20, 2023 at 06:47:10PM +0100, andrey.konovalov@xxxxxxxxx wrote: > > From: Andrey Konovalov <andreyknvl@xxxxxxxxxx> > > > > Currently, stack depot uses the following locking scheme: > > > > 1. Lock-free accesses when looking up a stack record, which allows to > > have multiple users to look up records in parallel; > > 2. Spinlock for protecting the stack depot pools and the hash table > > when adding a new record. > > > > For implementing the eviction of stack traces from stack depot, the > > lock-free approach is not going to work anymore, as we will need to be > > able to also remove records from the hash table. > > > > Convert the spinlock into a read/write lock, and drop the atomic accesses, > > as they are no longer required. > > > > Looking up stack traces is now protected by the read lock and adding new > > records - by the write lock. One of the following patches will add a new > > function for evicting stack records, which will be protected by the write > > lock as well. > > > > With this change, multiple users can still look up records in parallel. > > > > This is preparatory patch for implementing the eviction of stack records > > from the stack depot. > > I am testing quite recent "debug" kernel (with KASAN, Lockdep, etc > enabled). This kernel is based on > 9f8413c4a66f2fb776d3dc3c9ed20bf435eb305e, and I found the following This version predates this series, as far as I can tell. Can you try linux-next? Thanks, -- Marco
