mm/vmalloc.c | 314 +++++++++++++++++++++++++-------------------------- 1 file changed, 155 insertions(+), 159 deletions(-)
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 -- 2.43.0
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
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