| Message ID | 20240301155417.1852290-1-rulin.huang@intel.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | mm/vmalloc: lock contention optimization under multi-threading | expand |
Hello, are there any issues with this patch that need to be modified? If there is any, we will modify it as soon as possible, thank you. On 2024/3/1 23:54, rulinhuang wrote: > Hi, > > This version has the rearrangement of macros from the previous one. > > We are not sure whether we have completely moved these macros and > their corresponding helper to the correct position. Could you please > help to check whether they are correct? > > ~ > > 1. Motivation > > When allocating a new memory area where the mapping address range is > known, it is observed that the vmap_node->busy.lock is acquired twice > but one of the acquisitions is actually unnecessary. > > 2. Design > > Among the two acquisitions, the first one occurs in the > alloc_vmap_area() function when inserting the vm area into the vm > mapping red-black tree, and the second one occurs in the > setup_vmalloc_vm() function when updating the properties of the vm, > such as flags and address, etc. > > Combine these two operations together in alloc_vmap_area(), which > improves scalability when the vmap_node->busy.lock is contended. > By doing so, the need to acquire the lock twice can also be eliminated > to once. > > 3. Test results > > With the above change, tested on intel sapphire rapids > platform(224 vcpu), a 4% performance improvement is gained on > stress-ng/pthread(https://github.com/ColinIanKing/stress-ng), > which is the stress test of thread creations. > > rulinhuang > > [v1] https://lore.kernel.org/all/20240207033059.1565623-1-rulin.huang@intel.com/ > [v2] https://lore.kernel.org/all/20240220090521.3316345-1-rulin.huang@intel.com/ > [v3] https://lore.kernel.org/all/20240221032905.11392-1-rulin.huang@intel.com/ > [v4] https://lore.kernel.org/all/20240222120536.216166-1-rulin.huang@intel.com/ > [v5] https://lore.kernel.org/all/20240223130318.112198-2-rulin.huang@intel.com/ > [v6] https://lore.kernel.org/lkml/aa8f0413-d055-4b49-bcd3-401e93e01c6d@intel.com/ > > > rulinhuang (2): > mm/vmalloc: Moved macros with no functional change happened > mm/vmalloc: Eliminated the lock contention from twice to once > > mm/vmalloc.c | 314 +++++++++++++++++++++++++-------------------------- > 1 file changed, 155 insertions(+), 159 deletions(-) > > > base-commit: 10c2cf5fe97647d68ee89b1f921e982e71519f20