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2018-01-31mm/page_alloc.c: fix typos in commentsShile Zhang
Link: http://lkml.kernel.org/r/1515485774-4768-1-git-send-email-zhangshile@gmail.com Signed-off-by: Shile Zhang <zhangshile@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31memcg: refactor mem_cgroup_resize_limit()Yu Zhao
mem_cgroup_resize_limit() and mem_cgroup_resize_memsw_limit() have identical logics. Refactor code so we don't need to keep two pieces of code that does same thing. Link: http://lkml.kernel.org/r/20180108224238.14583-1-yuzhao@google.com Signed-off-by: Yu Zhao <yuzhao@google.com> Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31zswap: only save zswap header when necessaryYu Zhao
We waste sizeof(swp_entry_t) for zswap header when using zsmalloc as zpool driver because zsmalloc doesn't support eviction. Add zpool_evictable() to detect if zpool is potentially evictable, and use it in zswap to avoid waste memory for zswap header. [yuzhao@google.com: The zpool->" prefix is a result of copy & paste] Link: http://lkml.kernel.org/r/20180110225626.110330-1-yuzhao@google.com Link: http://lkml.kernel.org/r/20180110224741.83751-1-yuzhao@google.com Signed-off-by: Yu Zhao <yuzhao@google.com> Acked-by: Dan Streetman <ddstreet@ieee.org> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Seth Jennings <sjenning@redhat.com> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31mm/fadvise: discard partial page if endbyte is also EOFshidao.ytt
During our recent testing with fadvise(FADV_DONTNEED), we find that if given offset/length is not page-aligned, the last page will not be discarded. The tool we use is vmtouch (https://hoytech.com/vmtouch/), we map a 10KB-sized file into memory and then try to run this tool to evict the whole file mapping, but the last single page always remains staying in the memory: $./vmtouch -e test_10K Files: 1 Directories: 0 Evicted Pages: 3 (12K) Elapsed: 2.1e-05 seconds $./vmtouch test_10K Files: 1 Directories: 0 Resident Pages: 1/3 4K/12K 33.3% Elapsed: 5.5e-05 seconds However when we test with an older kernel, say 3.10, this problem is gone. So we wonder if this is a regression: $./vmtouch -e test_10K Files: 1 Directories: 0 Evicted Pages: 3 (12K) Elapsed: 8.2e-05 seconds $./vmtouch test_10K Files: 1 Directories: 0 Resident Pages: 0/3 0/12K 0% <-- partial page also discarded Elapsed: 5e-05 seconds After digging a little bit into this problem, we find it seems not a regression. Not discarding partial page is likely to be on purpose according to commit 441c228f817f ("mm: fadvise: document the fadvise(FADV_DONTNEED) behaviour for partial pages") written by Mel Gorman. He explained why partial pages should be preserved instead of being discarded when using fadvise(FADV_DONTNEED). However, the interesting part is that the actual code did NOT work as the same as it was described, the partial page was still discarded anyway, due to a calculation mistake of `end_index' passed to invalidate_mapping_pages(). This mistake has not been fixed until recently, that's why we fail to reproduce our problem in old kernels. The fix is done in commit 18aba41cbf ("mm/fadvise.c: do not discard partial pages with POSIX_FADV_DONTNEED") by Oleg Drokin. Back to the original testing, our problem becomes that there is a special case that, if the page-unaligned `endbyte' is also the end of file, it is not necessary at all to preserve the last partial page, as we all know no one else will use the rest of it. It should be safe enough if we just discard the whole page. So we add an EOF check in this patch. We also find a poosbile real world issue in mainline kernel. Assume such scenario: A userspace backup application want to backup a huge amount of small files (<4k) at once, the developer might (I guess) want to use fadvise(FADV_DONTNEED) to save memory. However, FADV_DONTNEED won't really happen since the only page mapped is a partial page, and kernel will preserve it. Our patch also fixes this problem, since we know the endbyte is EOF, so we discard it. Here is a simple reproducer to reproduce and verify each scenario we described above: test_fadvise.c ============================== #include <sys/mman.h> #include <sys/stat.h> #include <fcntl.h> #include <stdlib.h> #include <string.h> #include <stdio.h> #include <unistd.h> int main(int argc, char **argv) { int i, fd, ret, len; struct stat buf; void *addr; unsigned char *vec; char *strbuf; ssize_t pagesize = getpagesize(); ssize_t filesize; fd = open(argv[1], O_RDWR|O_CREAT, S_IRUSR|S_IWUSR); if (fd < 0) return -1; filesize = strtoul(argv[2], NULL, 10); strbuf = malloc(filesize); memset(strbuf, 42, filesize); write(fd, strbuf, filesize); free(strbuf); fsync(fd); len = (filesize + pagesize - 1) / pagesize; printf("length of pages: %d\n", len); addr = mmap(NULL, filesize, PROT_READ, MAP_SHARED, fd, 0); if (addr == MAP_FAILED) return -1; ret = posix_fadvise(fd, 0, filesize, POSIX_FADV_DONTNEED); if (ret < 0) return -1; vec = malloc(len); ret = mincore(addr, filesize, (void *)vec); if (ret < 0) return -1; for (i = 0; i < len; i++) printf("pages[%d]: %x\n", i, vec[i] & 0x1); free(vec); close(fd); return 0; } ============================== Test 1: running on kernel with commit 18aba41cbf reverted: [root@caspar ~]# uname -r 4.15.0-rc6.revert+ [root@caspar ~]# ./test_fadvise file1 1024 length of pages: 1 pages[0]: 0 # <-- partial page discarded [root@caspar ~]# ./test_fadvise file2 8192 length of pages: 2 pages[0]: 0 pages[1]: 0 [root@caspar ~]# ./test_fadvise file3 10240 length of pages: 3 pages[0]: 0 pages[1]: 0 pages[2]: 0 # <-- partial page discarded Test 2: running on mainline kernel: [root@caspar ~]# uname -r 4.15.0-rc6+ [root@caspar ~]# ./test_fadvise test1 1024 length of pages: 1 pages[0]: 1 # <-- partial and the only page not discarded [root@caspar ~]# ./test_fadvise test2 8192 length of pages: 2 pages[0]: 0 pages[1]: 0 [root@caspar ~]# ./test_fadvise test3 10240 length of pages: 3 pages[0]: 0 pages[1]: 0 pages[2]: 1 # <-- partial page not discarded Test 3: running on kernel with this patch: [root@caspar ~]# uname -r 4.15.0-rc6.patched+ [root@caspar ~]# ./test_fadvise test1 1024 length of pages: 1 pages[0]: 0 # <-- partial page and EOF, discarded [root@caspar ~]# ./test_fadvise test2 8192 length of pages: 2 pages[0]: 0 pages[1]: 0 [root@caspar ~]# ./test_fadvise test3 10240 length of pages: 3 pages[0]: 0 pages[1]: 0 pages[2]: 0 # <-- partial page and EOF, discarded [akpm@linux-foundation.org: tweak code comment] Link: http://lkml.kernel.org/r/5222da9ee20e1695eaabb69f631f200d6e6b8876.1515132470.git.jinli.zjl@alibaba-inc.com Signed-off-by: shidao.ytt <shidao.ytt@alibaba-inc.com> Signed-off-by: Caspar Zhang <jinli.zjl@alibaba-inc.com> Reviewed-by: Oliver Yang <zhiche.yy@alibaba-inc.com> Cc: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31mm: pin address_space before dereferencing it while isolating an LRU pageMel Gorman
Minchan Kim asked the following question -- what locks protects address_space destroying when race happens between inode trauncation and __isolate_lru_page? Jan Kara clarified by describing the race as follows CPU1 CPU2 truncate(inode) __isolate_lru_page() ... truncate_inode_page(mapping, page); delete_from_page_cache(page) spin_lock_irqsave(&mapping->tree_lock, flags); __delete_from_page_cache(page, NULL) page_cache_tree_delete(..) ... mapping = page_mapping(page); page->mapping = NULL; ... spin_unlock_irqrestore(&mapping->tree_lock, flags); page_cache_free_page(mapping, page) put_page(page) if (put_page_testzero(page)) -> false - inode now has no pages and can be freed including embedded address_space if (mapping && !mapping->a_ops->migratepage) - we've dereferenced mapping which is potentially already free. The race is theoretically possible but unlikely. Before the delete_from_page_cache, truncate_cleanup_page is called so the page is likely to be !PageDirty or PageWriteback which gets skipped by the only caller that checks the mappping in __isolate_lru_page. Even if the race occurs, a substantial amount of work has to happen during a tiny window with no preemption but it could potentially be done using a virtual machine to artifically slow one CPU or halt it during the critical window. This patch should eliminate the race with truncation by try-locking the page before derefencing mapping and aborting if the lock was not acquired. There was a suggestion from Huang Ying to use RCU as a side-effect to prevent mapping being freed. However, I do not like the solution as it's an unconventional means of preserving a mapping and it's not a context where rcu_read_lock is obviously protecting rcu data. Link: http://lkml.kernel.org/r/20180104102512.2qos3h5vqzeisrek@techsingularity.net Fixes: c82449352854 ("mm: compaction: make isolate_lru_page() filter-aware again") Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Minchan Kim <minchan@kernel.org> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31userfaultfd: convert to use anon_inode_getfd()Eric Biggers
Nothing actually calls userfaultfd_file_create() besides the userfaultfd() system call itself. So simplify things by folding it into the system call and using anon_inode_getfd() instead of anon_inode_getfile(). Do the same in resolve_userfault_fork() as well. This removes over 50 lines with no change in functionality. Link: http://lkml.kernel.org/r/20171229212403.22800-1-ebiggers3@gmail.com Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31memfd-test: run fuse test on hugetlb backend memoryMarc-André Lureau
Link: http://lkml.kernel.org/r/20171107122800.25517-10-marcandre.lureau@redhat.com Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Suggested-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: David Herrmann <dh.herrmann@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31memfd-test: move common code to a shared unitMarc-André Lureau
The memfd & fuse tests will share more common code in the following commits to test hugetlb support. Link: http://lkml.kernel.org/r/20171107122800.25517-9-marcandre.lureau@redhat.com Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: David Herrmann <dh.herrmann@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31memfd-test: add 'memfd-hugetlb:' prefix when testing hugetlbfsMarc-André Lureau
Link: http://lkml.kernel.org/r/20171107122800.25517-8-marcandre.lureau@redhat.com Suggested-by: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: David Herrmann <dh.herrmann@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31memfd-test: test hugetlbfs sealingMarc-André Lureau
Remove most of the special-casing of hugetlbfs now that sealing is supported. Link: http://lkml.kernel.org/r/20171107122800.25517-7-marcandre.lureau@redhat.com Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: David Herrmann <dh.herrmann@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31shmem: add sealing support to hugetlb-backed memfdMarc-André Lureau
Adapt add_seals()/get_seals() to work with hugetbfs-backed memory. Teach memfd_create() to allow sealing operations on MFD_HUGETLB. Link: http://lkml.kernel.org/r/20171107122800.25517-6-marcandre.lureau@redhat.com Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: David Herrmann <dh.herrmann@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31hugetlb: implement memfd sealingMarc-André Lureau
Implements memfd sealing, similar to shmem: - WRITE: deny fallocate(PUNCH_HOLE). mmap() write is denied in memfd_add_seals(). write() doesn't exist for hugetlbfs. - SHRINK: added similar check as shmem_setattr() - GROW: added similar check as shmem_setattr() & shmem_fallocate() Except write() operation that doesn't exist with hugetlbfs, that should make sealing as close as it can be to shmem support. Link: http://lkml.kernel.org/r/20171107122800.25517-5-marcandre.lureau@redhat.com Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: David Herrmann <dh.herrmann@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31hugetlb: expose hugetlbfs_inode_info in headerMarc-André Lureau
hugetlbfs inode information will need to be accessed by code in mm/shmem.c for file sealing operations. Move inode information definition from .c file to header for needed access. Link: http://lkml.kernel.org/r/20171107122800.25517-4-marcandre.lureau@redhat.com Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: David Herrmann <dh.herrmann@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31shmem: rename functions that are memfd-relatedMarc-André Lureau
Those functions are called for memfd files, backed by shmem or hugetlb (the next patches will handle hugetlb). Link: http://lkml.kernel.org/r/20171107122800.25517-3-marcandre.lureau@redhat.com Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: David Herrmann <dh.herrmann@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31shmem: unexport shmem_add_seals()/shmem_get_seals()Marc-André Lureau
Patch series "memfd: add sealing to hugetlb-backed memory", v3. Recently, Mike Kravetz added hugetlbfs support to memfd. However, he didn't add sealing support. One of the reasons to use memfd is to have shared memory sealing when doing IPC or sharing memory with another process with some extra safety. qemu uses shared memory & hugetables with vhost-user (used by dpdk), so it is reasonable to use memfd now instead for convenience and security reasons. This patch (of 9): The functions are called through shmem_fcntl() only. And no danger in removing the EXPORTs as the routines only work with shmem file structs. Link: http://lkml.kernel.org/r/20171107122800.25517-2-marcandre.lureau@redhat.com Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: David Herrmann <dh.herrmann@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31mm: remove reference to PG_buddyMatthew Wilcox
PG_buddy doesn't exist any more. It's called PageBuddy now. Link: http://lkml.kernel.org/r/20171220155552.15884-9-willy@infradead.org Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Christoph Lameter <cl@linux.com> Cc: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31mm: document how to use struct pageMatthew Wilcox
Be really explicit about what bits / bytes are reserved for users that want to store extra information about the pages they allocate. Link: http://lkml.kernel.org/r/20171220155552.15884-8-willy@infradead.org Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Randy Dunlap <rdunlap@infradead.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Christoph Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31mm: store compound_dtor / compound_order as bytesMatthew Wilcox
Neither of these values get even close to 256; compound_dtor is currently at a maximum of 3, and compound_order can't be over 64. No machine has inefficient access to bytes since EV5, and while those are still supported, we don't optimise for them any more. This does not shrink struct page, but it removes an ifdef and frees up 2-6 bytes for future use. diff of pahole output: struct callback_head callback_head; /* 32 16 */ struct { long unsigned int compound_head; /* 32 8 */ - unsigned int compound_dtor; /* 40 4 */ - unsigned int compound_order; /* 44 4 */ + unsigned char compound_dtor; /* 40 1 */ + unsigned char compound_order; /* 41 1 */ }; /* 32 16 */ }; /* 32 16 */ union { [mawilcox@microsoft.com: add comment] Link: http://lkml.kernel.org/r/20171221000144.GB2980@bombadil.infradead.org Link: http://lkml.kernel.org/r/20171220155552.15884-7-willy@infradead.org Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Christoph Lameter <cl@linux.com> Cc: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31mm: introduce _slub_counter_tMatthew Wilcox
Instead of putting the ifdef in the middle of the definition of struct page, pull it forward to the rest of the ifdeffery around the SLUB cmpxchg_double optimisation. Link: http://lkml.kernel.org/r/20171220155552.15884-6-willy@infradead.org Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Christoph Lameter <cl@linux.com> Cc: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31mm: improve comment on page->mappingMatthew Wilcox
The comment on page->mapping is terse, and out of date (it does not mention the possibility of PAGE_MAPPING_MOVABLE). Instead, point the interested reader to page-flags.h where there is a much better comment. Link: http://lkml.kernel.org/r/20171220155552.15884-5-willy@infradead.org Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Christoph Lameter <cl@linux.com> Cc: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31mm: remove misleading alignment claimsMatthew Wilcox
The "third double word block" isn't on 32-bit systems. The layout looks like this: unsigned long flags; struct address_space *mapping pgoff_t index; atomic_t _mapcount; atomic_t _refcount; which is 32 bytes on 64-bit, but 20 bytes on 32-bit. Nobody is trying to use the fact that it's double-word aligned today, so just remove the misleading claims. Link: http://lkml.kernel.org/r/20171220155552.15884-4-willy@infradead.org Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Christoph Lameter <cl@linux.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31mm: de-indent struct pageMatthew Wilcox
I found the struct { union { struct { union { struct { } } } } } layout rather confusing. Fortunately, there is an easier way to write this. The innermost union is of four things which are the size of an int, so the ones which are used by slab/slob/slub can be pulled up two levels to be in the outermost union with 'counters'. That leaves us with struct { union { struct { atomic_t; atomic_t; } } } which has the same layout, but is easier to read. Output from the current git version of pahole, diffed with -uw to ignore the whitespace changes from the indentation: }; /* 16 8 */ union { long unsigned int counters; /* 24 8 */ - struct { - union { - atomic_t _mapcount; /* 24 4 */ unsigned int active; /* 24 4 */ struct { unsigned int inuse:16; /* 24:16 4 */ @@ -21,7 +18,8 @@ unsigned int frozen:1; /* 24: 0 4 */ }; /* 24 4 */ int units; /* 24 4 */ - }; /* 24 4 */ + struct { + atomic_t _mapcount; /* 24 4 */ atomic_t _refcount; /* 28 4 */ }; /* 24 8 */ }; /* 24 8 */ Link: http://lkml.kernel.org/r/20171220155552.15884-3-willy@infradead.org Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Christoph Lameter <cl@linux.com> Cc: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31mm: align struct page more aestheticallyMatthew Wilcox
Patch series "Restructure struct page", v2. This series does not attempt any grand restructuring. Instead, it cures the worst of the indentitis, fixes the documentation and reduces the ifdeffery. The only layout change is compound_dtor and compound_order are each reduced to one byte. This patch (of 8): Instead of an ifdef block at the end of the struct, which needed its own comment, define _struct_page_alignment up at the top where it fits nicely with the existing comment. Link: http://lkml.kernel.org/r/20171220155552.15884-2-willy@infradead.org Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Christoph Lameter <cl@linux.com> Cc: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31mm/zsmalloc: simplify shrinker init/destroyAliaksei Karaliou
Structure zs_pool has special flag to indicate success of shrinker initialization. unregister_shrinker() has improved and can detect by itself whether actual deinitialization should be performed or not, so extra flag becomes redundant. [akpm@linux-foundation.org: update comment (Aliaksei), remove unneeded cast] Link: http://lkml.kernel.org/r/1513680552-9798-1-git-send-email-akaraliou.dev@gmail.com Signed-off-by: Aliaksei Karaliou <akaraliou.dev@gmail.com> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31mm, oom: avoid reaping only for mm's with blockable invalidate callbacksDavid Rientjes
This uses the new annotation to determine if an mm has mmu notifiers with blockable invalidate range callbacks to avoid oom reaping. Otherwise, the callbacks are used around unmap_page_range(). Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1712141330120.74052@chino.kir.corp.google.com Signed-off-by: David Rientjes <rientjes@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Christian König <christian.koenig@amd.com> Cc: Dimitri Sivanich <sivanich@hpe.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Oded Gabbay <oded.gabbay@gmail.com> Cc: Alex Deucher <alexander.deucher@amd.com> Cc: David Airlie <airlied@linux.ie> Cc: Joerg Roedel <joro@8bytes.org> Cc: Doug Ledford <dledford@redhat.com> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Mike Marciniszyn <mike.marciniszyn@intel.com> Cc: Sean Hefty <sean.hefty@intel.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31mm, mmu_notifier: annotate mmu notifiers with blockable invalidate callbacksDavid Rientjes
Commit 4d4bbd8526a8 ("mm, oom_reaper: skip mm structs with mmu notifiers") prevented the oom reaper from unmapping private anonymous memory with the oom reaper when the oom victim mm had mmu notifiers registered. The rationale is that doing mmu_notifier_invalidate_range_{start,end}() around the unmap_page_range(), which is needed, can block and the oom killer will stall forever waiting for the victim to exit, which may not be possible without reaping. That concern is real, but only true for mmu notifiers that have blockable invalidate_range_{start,end}() callbacks. This patch adds a "flags" field to mmu notifier ops that can set a bit to indicate that these callbacks do not block. The implementation is steered toward an expensive slowpath, such as after the oom reaper has grabbed mm->mmap_sem of a still alive oom victim. [rientjes@google.com: mmu_notifier_invalidate_range_end() can also call the invalidate_range() must not block, fix comment] Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1801091339570.240101@chino.kir.corp.google.com [akpm@linux-foundation.org: make mm_has_blockable_invalidate_notifiers() return bool, use rwsem_is_locked()] Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1712141329500.74052@chino.kir.corp.google.com Signed-off-by: David Rientjes <rientjes@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Acked-by: Christian König <christian.koenig@amd.com> Acked-by: Dimitri Sivanich <sivanich@hpe.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Oded Gabbay <oded.gabbay@gmail.com> Cc: Alex Deucher <alexander.deucher@amd.com> Cc: David Airlie <airlied@linux.ie> Cc: Joerg Roedel <joro@8bytes.org> Cc: Doug Ledford <dledford@redhat.com> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Mike Marciniszyn <mike.marciniszyn@intel.com> Cc: Sean Hefty <sean.hefty@intel.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31mm: thp: use down_read_trylock() in khugepaged to avoid long blockYang Shi
In the current design, khugepaged needs to acquire mmap_sem before scanning an mm. But in some corner cases, khugepaged may scan a process which is modifying its memory mapping, so khugepaged blocks in uninterruptible state. But the process might hold the mmap_sem for a long time when modifying a huge memory space and it may trigger the below khugepaged hung issue: INFO: task khugepaged:270 blocked for more than 120 seconds. Tainted: G E 4.9.65-006.ali3000.alios7.x86_64 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. khugepaged D 0 270 2 0x00000000  ffff883f3deae4c0 0000000000000000 ffff883f610596c0 ffff883f7d359440 ffff883f63818000 ffffc90019adfc78 ffffffff817079a5 d67e5aa8c1860a64 0000000000000246 ffff883f7d359440 ffffc90019adfc88 ffff883f610596c0 Call Trace: schedule+0x36/0x80 rwsem_down_read_failed+0xf0/0x150 call_rwsem_down_read_failed+0x18/0x30 down_read+0x20/0x40 khugepaged+0x476/0x11d0 kthread+0xe6/0x100 ret_from_fork+0x25/0x30 So it sounds pointless to just block khugepaged waiting for the semaphore so replace down_read() with down_read_trylock() to move to scan the next mm quickly instead of just blocking on the semaphore so that other processes can get more chances to install THP. Then khugepaged can come back to scan the skipped mm when it has finished the current round full_scan. And it appears that the change can improve khugepaged efficiency a little bit. Below is the test result when running LTP on a 24 cores 4GB memory 2 nodes NUMA VM: pristine w/ trylock full_scan 197 187 pages_collapsed 21 26 thp_fault_alloc 40818 44466 thp_fault_fallback 18413 16679 thp_collapse_alloc 21 150 thp_collapse_alloc_failed 14 16 thp_file_alloc 369 369 [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: tweak comment] [arnd@arndb.de: avoid uninitialized variable use] Link: http://lkml.kernel.org/r/20171215125129.2948634-1-arnd@arndb.de Link: http://lkml.kernel.org/r/1513281203-54878-1-git-send-email-yang.s@alibaba-inc.com Signed-off-by: Yang Shi <yang.s@alibaba-inc.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Hugh Dickins <hughd@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31mm/thp: remove pmd_huge_split_prepare()Aneesh Kumar K.V
Instead of marking the pmd ready for split, invalidate the pmd. This should take care of powerpc requirement. Only side effect is that we mark the pmd invalid early. This can result in us blocking access to the page a bit longer if we race against a thp split. [kirill.shutemov@linux.intel.com: rebased, dirty THP once] Link: http://lkml.kernel.org/r/20171213105756.69879-13-kirill.shutemov@linux.intel.com Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Daney <david.daney@cavium.com> Cc: David Miller <davem@davemloft.net> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Nitin Gupta <nitin.m.gupta@oracle.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31mm: use updated pmdp_invalidate() interface to track dirty/accessed bitsKirill A. Shutemov
Use the modifed pmdp_invalidate() that returns the previous value of pmd to transfer dirty and accessed bits. Link: http://lkml.kernel.org/r/20171213105756.69879-12-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Daney <david.daney@cavium.com> Cc: David Miller <davem@davemloft.net> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Nitin Gupta <nitin.m.gupta@oracle.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31mm: do not lose dirty and accessed bits in pmdp_invalidate()Kirill A. Shutemov
Vlastimil noted that pmdp_invalidate() is not atomic and we can lose dirty and access bits if CPU sets them after pmdp dereference, but before set_pmd_at(). The patch change pmdp_invalidate() to make the entry non-present atomically and return previous value of the entry. This value can be used to check if CPU set dirty/accessed bits under us. The race window is very small and I haven't seen any reports that can be attributed to the bug. For this reason, I don't think backporting to stable trees needed. Link: http://lkml.kernel.org/r/20171213105756.69879-11-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Daney <david.daney@cavium.com> Cc: David Miller <davem@davemloft.net> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Nitin Gupta <nitin.m.gupta@oracle.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vineet Gupta <vgupta@synopsys.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31x86/mm: provide pmdp_establish() helperKirill A. Shutemov
We need an atomic way to setup pmd page table entry, avoiding races with CPU setting dirty/accessed bits. This is required to implement pmdp_invalidate() that doesn't lose these bits. On PAE we can avoid expensive cmpxchg8b for cases when new page table entry is not present. If it's present, fallback to cpmxchg loop. [akpm@linux-foundation.org: add missing `do' to do-while loop] Link: http://lkml.kernel.org/r/20171213105756.69879-10-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31sparc64: update pmdp_invalidate() to return old pmd valueNitin Gupta
It's required to avoid losing dirty and accessed bits. [akpm@linux-foundation.org: add a `do' to the do-while loop] Link: http://lkml.kernel.org/r/20171213105756.69879-9-kirill.shutemov@linux.intel.com Signed-off-by: Nitin Gupta <nitin.m.gupta@oracle.com> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: David Miller <davem@davemloft.net> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31s390/mm: modify pmdp_invalidate to return old value.Martin Schwidefsky
It's required to avoid losing dirty and accessed bits. Link: http://lkml.kernel.org/r/20171213105756.69879-8-kirill.shutemov@linux.intel.com Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31powerpc/mm: update pmdp_invalidate to return old pmd valueAneesh Kumar K.V
It's required to avoid losing dirty and accessed bits. Link: http://lkml.kernel.org/r/20171213105756.69879-7-kirill.shutemov@linux.intel.com Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31mips: use generic_pmdp_establish as pmdp_establishKirill A. Shutemov
MIPS doesn't support hardware dirty/accessed bits. generic_pmdp_establish() is suitable in this case. Link: http://lkml.kernel.org/r/20171213105756.69879-6-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: David Daney <david.daney@cavium.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31arm64: provide pmdp_establish() helperCatalin Marinas
We need an atomic way to setup pmd page table entry, avoiding races with CPU setting dirty/accessed bits. This is required to implement pmdp_invalidate() that doesn't lose these bits. Link: http://lkml.kernel.org/r/20171213105756.69879-5-kirill.shutemov@linux.intel.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31arm/mm: provide pmdp_establish() helperKirill A. Shutemov
ARM LPAE doesn't have hardware dirty/accessed bits. generic_pmdp_establish() is the right implementation of pmdp_establish for this case. Link: http://lkml.kernel.org/r/20171213105756.69879-4-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31arc: use generic_pmdp_establish as pmdp_establishKirill A. Shutemov
ARC doesn't support hardware dirty/accessed bits. generic_pmdp_establish() is suitable in this case. Link: http://lkml.kernel.org/r/20171213105756.69879-3-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31asm-generic: provide generic_pmdp_establish()Kirill A. Shutemov
Patch series "Do not lose dirty bit on THP pages", v4. Vlastimil noted that pmdp_invalidate() is not atomic and we can lose dirty and access bits if CPU sets them after pmdp dereference, but before set_pmd_at(). The bug can lead to data loss, but the race window is tiny and I haven't seen any reports that suggested that it happens in reality. So I don't think it worth sending it to stable. Unfortunately, there's no way to address the issue in a generic way. We need to fix all architectures that support THP one-by-one. All architectures that have THP supported have to provide atomic pmdp_invalidate() that returns previous value. If generic implementation of pmdp_invalidate() is used, architecture needs to provide atomic pmdp_estabish(). pmdp_estabish() is not used out-side generic implementation of pmdp_invalidate() so far, but I think this can change in the future. This patch (of 12): This is an implementation of pmdp_establish() that is only suitable for an architecture that doesn't have hardware dirty/accessed bits. In this case we can't race with CPU which sets these bits and non-atomic approach is fine. Link: http://lkml.kernel.org/r/20171213105756.69879-2-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Daney <david.daney@cavium.com> Cc: David Miller <davem@davemloft.net> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Nitin Gupta <nitin.m.gupta@oracle.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vineet Gupta <vgupta@synopsys.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31mm: get 7% more pages in a pagevecMatthew Wilcox
We don't have to use an entire 'long' for the number of elements in the pagevec; we know it's a number between 0 and 14 (now 15). So we can store it in a char, and then the bool packs next to it and we still have two or six bytes of padding for more elements in the header. That gives us space to cram in an extra page. Link: http://lkml.kernel.org/r/20171206022521.GM26021@bombadil.infradead.org Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31mm: add unmap_mapping_pages()Matthew Wilcox
Several users of unmap_mapping_range() would prefer to express their range in pages rather than bytes. Unfortuately, on a 32-bit kernel, you have to remember to cast your page number to a 64-bit type before shifting it, and four places in the current tree didn't remember to do that. That's a sign of a bad interface. Conveniently, unmap_mapping_range() actually converts from bytes into pages, so hoist the guts of unmap_mapping_range() into a new function unmap_mapping_pages() and convert the callers which want to use pages. Link: http://lkml.kernel.org/r/20171206142627.GD32044@bombadil.infradead.org Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Reported-by: "zhangyi (F)" <yi.zhang@huawei.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31mm, userfaultfd, THP: avoid waiting when PMD under THP migrationHuang Ying
If THP migration is enabled, for a VMA handled by userfaultfd, consider the following situation, do_page_fault() __do_huge_pmd_anonymous_page() handle_userfault() userfault_msg() /* a huge page is allocated and mapped at fault address */ /* the huge page is under migration, leaves migration entry in page table */ userfaultfd_must_wait() /* return true because !pmd_present() */ /* may wait in loop until fatal signal */ That is, it may be possible for userfaultfd_must_wait() encounters a PMD entry which is !pmd_none() && !pmd_present(). In the current implementation, we will wait for such PMD entries, which may cause unnecessary waiting, and potential soft lockup. This is fixed via avoiding to wait when !pmd_none() && !pmd_present(), only wait when pmd_none(). This may be not a problem in practice, because userfaultfd_must_wait() is always called with mm->mmap_sem read-locked. mremap() will write-lock mm->mmap_sem. And UFFDIO_COPY doesn't support to copy THP mapping. But the change introduced still makes the code more correct, and makes the PMD and PTE code more consistent. Link: http://lkml.kernel.org/r/20171207011752.3292-1-ying.huang@intel.com Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Alexander Viro <viro@zeniv.linux.org.UK> Cc: Zi Yan <zi.yan@cs.rutgers.edu> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31mm/huge_memory.c: fix comment in __split_huge_pmd_lockedYisheng Xie
pmd_trans_splitting() was removed after THP refcounting redesign, therefore related comment should be updated. Link: http://lkml.kernel.org/r/1512625745-59451-1-git-send-email-xieyisheng1@huawei.com Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31mm: memory_hotplug: remove second __nr_to_section in ↵Oscar Salvador
register_page_bootmem_info_section() In register_page_bootmem_info_section() we call __nr_to_section() in order to get the mem_section struct at the beginning of the function. Since we already got it, there is no need for a second call to __nr_to_section(). Link: http://lkml.kernel.org/r/20171207102914.GA12396@techadventures.net Signed-off-by: Oscar Salvador <osalvador@techadventures.net> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31fs/proc/task_mmu.c: do not show VmExe bigger than total executable virtual ↵Konstantin Khlebnikov
memory If start_code / end_code pointers are screwed then "VmExe" could be bigger than total executable virtual memory and "VmLib" becomes negative: VmExe: 294320 kB VmLib: 18446744073709327564 kB VmExe and VmLib documented as text segment and shared library code size. Now their sum will be always equal to mm->exec_vm which sums size of executable and not writable and not stack areas. I've seen this for huge (>2Gb) statically linked binary which has whole world inside. For it start_code .. end_code range also covers one of rodata sections. Probably this is bug in customized linker, elf loader or both. Anyway CONFIG_CHECKPOINT_RESTORE allows to change these pointers, thus we cannot trust them without validation. Link: http://lkml.kernel.org/r/150728955451.743749.11276392315459539583.stgit@buzz Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Acked-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31mm: update comment describing tlb_gather_mmuMike Rapoport
The comment describes @fullmm argument, but the function has no such parameter. Update the comment to match the code and convert it to kernel-doc markup. Link: http://lkml.kernel.org/r/1512394531-2264-1-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31mm/memory_hotplug.c: remove unnecesary check from ↵Oscar Salvador
register_page_bootmem_info_section() When we call register_page_bootmem_info_section() having CONFIG_SPARSEMEM_VMEMMAP enabled, we check if the pfn is valid. This check is redundant as we already checked this in register_page_bootmem_info_node() before calling register_page_bootmem_info_section(), so let's get rid of it. Link: http://lkml.kernel.org/r/20171205143422.GA31458@techadventures.net Signed-off-by: Oscar Salvador <osalvador@techadventures.net> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31mm, hugetlb: remove hugepages_treat_as_movable sysctlMichal Hocko
hugepages_treat_as_movable has been introduced by 396faf0303d2 ("Allow huge page allocations to use GFP_HIGH_MOVABLE") to allow hugetlb allocations from ZONE_MOVABLE even when hugetlb pages were not migrateable. The purpose of the movable zone was different at the time. It aimed at reducing memory fragmentation and hugetlb pages being long lived and large werre not contributing to the fragmentation so it was acceptable to use the zone back then. Things have changed though and the primary purpose of the zone became migratability guarantee. If we allow non migrateable hugetlb pages to be in ZONE_MOVABLE memory hotplug might fail to offline the memory. Remove the knob and only rely on hugepage_migration_supported to allow movable zones. Mel said: : Primarily it was aimed at allowing the hugetlb pool to safely shrink with : the ability to grow it again. The use case was for batched jobs, some of : which needed huge pages and others that did not but didn't want the memory : useless pinned in the huge pages pool. : : I suspect that more users rely on THP than hugetlbfs for flexible use of : huge pages with fallback options so I think that removing the option : should be ok. Link: http://lkml.kernel.org/r/20171003072619.8654-1-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: Alexandru Moise <00moses.alexander00@gmail.com> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Alexandru Moise <00moses.alexander00@gmail.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31mm: remove unused pgdat_reclaimable_pages()Jan Kara
Remove unused function pgdat_reclaimable_pages() and node_page_state_snapshot() which becomes unused as well. Link: http://lkml.kernel.org/r/20171122094416.26019-1-jack@suse.cz Signed-off-by: Jan Kara <jack@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31mm/interval_tree.c: use vma_pages() helperVasyl Gomonovych
Use vma_pages function on vma object instead of explicit computation. mm/interval_tree.c:21:27-33: WARNING: Consider using vma_pages helper Generated by: scripts/coccinelle/api/vma_pages.cocci Link: http://lkml.kernel.org/r/1511364410-13499-1-git-send-email-gomonovych@gmail.com Signed-off-by: Vasyl Gomonovych <gomonovych@gmail.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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