On 07/10/23 16:04, Sidhartha Kumar wrote: > ========================== OVERVIEW ======================================== > This patchset attempts to implement a listed filemap TODO which is > changing hugetlb folios to have ->index in PAGE_SIZE. This simplifies many > functions within filemap.c as they have to special case hugetlb pages. > From the RFC v1[1], Mike pointed out that hugetlb will still have to maintain > a huge page sized index as it is used for the reservation map and the hash > function for the hugetlb mutex table. > > This patchset adds new wrappers for hugetlb code to to interact with the > page cache. These wrappers calculate a linear page index as this is now > what the page cache expects for hugetlb pages. > > From the discussion on HGM for hugetlb[3], there is a want to remove hugetlb > special casing throughout the core mm code. This series accomplishes > a part of this by shifting complexity from filemap.c to hugetlb.c. There > are still checks for hugetlb within the filemap code as cgroup accounting > and hugetlb accounting are special cased as well. > > =========================== PERFORMANCE ===================================== Hi Sid, Sorry for being dense but can you tell me what the below performance information means. My concern with such a change would be any noticeable difference in populating a large (up to TB) hugetlb file. My guess is that it is going to take longer unless xarray is optimized for this. We do have users that create and pre-populate hugetlb files this big. Just want to make sure there are no surprises for them. -- Mike Kravetz > 6.4.0-rc5 > @hugetlb_add_to_page_cache: > [512, 1K) 7518 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@| > [1K, 2K) 158 |@ | > [2K, 4K) 30 | | > [4K, 8K) 6 | | > [8K, 16K) 9 | > > 6.5.0-rc1 + this patch series > @hugetlb_add_to_page_cache: > [512, 1K) 6345 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@| > [1K, 2K) 1308 |@@@@@@@@@@ | > [2K, 4K) 39 | | > [4K, 8K) 20 | | > [8K, 16K) 8 | | > [16K, 32K) 1 | | > > 6.4.0-rc5 > @__filemap_get_folio: > [256, 512) 11292 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@| > [512, 1K) 4615 |@@@@@@@@@@@@@@@@@@@@@ | > [1K, 2K) 960 |@@@@ | > [2K, 4K) 188 | | > [4K, 8K) 68 | | > [8K, 16K) 14 | | > [16K, 32K) 4 | | > [2G, 4G) 4 | | > > 6.5.0-rc1 + this patch series > @__filemap_get_folio: > @get_folio_ns: > [128, 256) 13 | | > [256, 512) 11131 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@| > [512, 1K) 5544 |@@@@@@@@@@@@@@@@@@@@@@@@@ | > [1K, 2K) 996 |@@@@ | > [2K, 4K) 317 |@ | > [4K, 8K) 76 | | > [8K, 16K) 23 | | > [16K, 32K) 6 | | > [32K, 64K) 1 | | > [64K, 128K) 0 | | > [128K, 256K) 0 | | > [256K, 512K) 0 | | > [512K, 1M) 0 | | > [1M, 2M) 0 | | > [2M, 4M) 0 | | > [4M, 8M) 0 | | > [8M, 16M) 0 | | > [16M, 32M) 0 | | > [32M, 64M) 0 | | > [64M, 128M) 0 | | > [128M, 256M) 0 | | > [256M, 512M) 0 | | > [512M, 1G) 0 | | > [1G, 2G) 0 | | > [2G, 4G) 3 | > > =========================== TESTING ========================================== > This series passes the LTP hugetlb test cases as well as the libhugetlbfs tests. > > ********** TEST SUMMARY > * 2M > * 32-bit 64-bit > * Total testcases: 110 113 > * Skipped: 0 0 > * PASS: 107 113 > * FAIL: 0 0 > * Killed by signal: 3 0 > * Bad configuration: 0 0 > * Expected FAIL: 0 0 > * Unexpected PASS: 0 0 > * Test not present: 0 0 > * Strange test result: 0 0 > ********** > > > > RFC v2[2]-> v1: > -cleanup code style > > RFC v1 -> v2 > -change direction of series to maintain both huge and base page size index > rather than try to get rid of all references to a huge page sized index. > > v1 -> v2 > - squash seperate filemap and hugetlb patches into one to allow for bisection > per Matthew > - get rid of page_to_index() > - fix errors in hugetlb_fallocate() and remove_inode_hugepages() > > > rebased on 07/10/2023 mm-unstable > > > Sidhartha Kumar (1): > mm/filemap: remove hugetlb special casing in filemap.c > > fs/hugetlbfs/inode.c | 10 +++++----- > include/linux/hugetlb.h | 12 ++++++++++++ > include/linux/pagemap.h | 26 ++------------------------ > mm/filemap.c | 36 +++++++++++------------------------- > mm/hugetlb.c | 11 ++++++----- > 5 files changed, 36 insertions(+), 59 deletions(-) > > -- > 2.41.0 >
