On Wed, 16 Oct 2024 12:53:15 +0100, willy@xxxxxxxxxxxxx wrote: >On Wed, Oct 16, 2024 at 12:36:00PM +0800, lizhe.67@xxxxxxxxxxxxx wrote: >> From: Li Zhe <lizhe.67@xxxxxxxxxxxxx> >> >> In function collapse_huge_page(), we drop mmap read lock and get >> mmap write lock to prevent most accesses to pagetables. There is >> a small time window to allow other tasks to acquire the mmap lock. >> With the use of upgrade_read(), we don't need to check vma and pmd >> again in most cases. > >This is clearly a performance optimisation. So you must have some >numebrs that justify this, please include them. Yes, I will add the relevant data to v2 patch. Thanks!
