These 3 changes are to improve the handling of large mm_populate and munlock operations. They apply on top of mmotm (in particular, they depend on both my prior mm_populate work and Kirill's "thp: avoid dumping huge zero page" change).
- Patch 1 fixes an integer overflow issue when populating 2^32 pages. The nr_pages argument to get_user_pages would overflow, resulting in 0 pages being processed per iteration. I am proposing to simply convert the nr_pages argument to an unsigned long. - Patch 2 accelerates populating regions with THP pages. get_user_pages() can increment the address by a huge page size in this case instead of a small page size, and avoid repeated mm->page_table_lock acquisitions. This fixes an issue reported by Roman Dubtsov where populating regions via mmap MAP_POPULATE was significantly slower than doing so by touching pages from userspace. - Patch 3 is a similar acceleration for the munlock case. Changes between v1 and v2: - Andrew accepted patch 1 into his -mm tree but suggested the nr_pages argument type should actually be unsigned long; I am sending this as a "fix" for the previous patch 1 to be collapsed over the previous one. - In patch 2, I am adding a separate follow_page_mask() function so that the callers to the original follow_page() don't have to be modified to ignore the returned page_mask (following another suggestion from Andrew). Also the page_mask argument type was changed to unsigned int. - In patch 3, I similarly changed the page_mask values to unsigned int. Changes between v2 and v3: - In patch 1, updated mm/nommu.c to match the updated gup function prototype and avoid breaking the nommu build. - In patch 1, removed incorrect VM_BUG_ON in mm/mlock.c - In patch 3, fixed munlock_vma_page() to return a page mask as expected by munlock_vma_pages_range() instead of a number of pages. Michel Lespinasse (3): mm: use long type for page counts in mm_populate() and get_user_pages() mm: accelerate mm_populate() treatment of THP pages mm: accelerate munlock() treatment of THP pages include/linux/hugetlb.h | 6 +++--- include/linux/mm.h | 28 +++++++++++++++++++--------- mm/hugetlb.c | 12 ++++++------ mm/internal.h | 2 +- mm/memory.c | 49 ++++++++++++++++++++++++++++++++----------------- mm/mlock.c | 38 +++++++++++++++++++++++++------------- mm/nommu.c | 21 ++++++++++++--------- 7 files changed, 98 insertions(+), 58 deletions(-) -- 1.8.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
