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authorCannon Matthews <cannonmatthews@google.com>2018-07-04 02:02:43 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2018-07-04 02:32:19 +0200
commit520495fe96d74e05db585fc748351e0504d8f40d (patch)
treec0e3a926ecefc43e56bfc0b8d71e86e01f78f5c9 /mm
parentuserfaultfd: hugetlbfs: fix userfaultfd_huge_must_wait() pte access (diff)
downloadlinux-520495fe96d74e05db585fc748351e0504d8f40d.tar.xz
linux-520495fe96d74e05db585fc748351e0504d8f40d.zip
mm: hugetlb: yield when prepping struct pages
When booting with very large numbers of gigantic (i.e. 1G) pages, the operations in the loop of gather_bootmem_prealloc, and specifically prep_compound_gigantic_page, takes a very long time, and can cause a softlockup if enough pages are requested at boot. For example booting with 3844 1G pages requires prepping (set_compound_head, init the count) over 1 billion 4K tail pages, which takes considerable time. Add a cond_resched() to the outer loop in gather_bootmem_prealloc() to prevent this lockup. Tested: Booted with softlockup_panic=1 hugepagesz=1G hugepages=3844 and no softlockup is reported, and the hugepages are reported as successfully setup. Link: http://lkml.kernel.org/r/20180627214447.260804-1-cannonmatthews@google.com Signed-off-by: Cannon Matthews <cannonmatthews@google.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Andres Lagar-Cavilla <andreslc@google.com> Cc: Peter Feiner <pfeiner@google.com> Cc: Greg Thelen <gthelen@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/hugetlb.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 3612fbb32e9d..039ddbc574e9 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2163,6 +2163,7 @@ static void __init gather_bootmem_prealloc(void)
*/
if (hstate_is_gigantic(h))
adjust_managed_page_count(page, 1 << h->order);
+ cond_resched();
}
}