Hi, > -----Original Message----- > From: Erez Ferber <[email protected]> > Sent: Wednesday, May 24, 2023 3:02 PM > To: [email protected] > Cc: Slava Ovsiienko <[email protected]>; Matan Azrad > <[email protected]>; Raslan Darawsheh <[email protected]>; Erez Ferber > <[email protected]>; [email protected] > Subject: [PATCH] common/mlx5: adjust fork call with the new kernel API > > From: Erez Ferber <[email protected]> > > While doing process fork() the operating system remaps all the parent > process's memory to the address space of the child process and activates > the Copy-on-Write mechanics - it duplicates physical pages once memory > writing happens in the child process. Sometimes memory duplication is > not allowed - for example, if the page contains hardware queue > descriptors. To handle similar issues the rdma-core library should be > prepared for forking. > > The ibv_fork_init() prepares the library to track all the related memory > and prevent it from forking using madvise() system API. This approach > allows fork, but not all the memory is forked to the child process and, > application should care not to touch pages where the parent application > allocated the rdma-core objects. > > The newer kernels propose an option of copy-on-fork for DMA pages and > tracking all the memory and disabling it for the forking is no longer > needed. The new API routine ibv_is_fork_initialized() should be involved > to decide if library initialization for forking is required. > > Fixes: 0e83b8e536 ("net/mlx5: move rdma-core calls to separate file") > Cc: [email protected] > Signed-off-by: Erez Ferber <[email protected]>
Patch applied to next-net-mlx, Kindest regards, Raslan Darawsheh
