mirror of
https://github.com/torvalds/linux.git
synced 2024-11-26 06:02:05 +00:00
ba925fa350
During s390_enable_sie(), we need to take care of splitting all qemu user process THP mappings. This is currently done with follow_page(FOLL_SPLIT), by simply iterating over all vma ranges, with PAGE_SIZE increment. This logic is sub-optimal and can result in a lot of unnecessary overhead, especially when using qemu and ASAN with large shadow map. Ilya reported significant system slow-down with one CPU busy for a long time and overall unresponsiveness. Fix this by using walk_page_vma() and directly calling split_huge_pmd() only for present pmds, which greatly reduces overhead. Cc: <stable@vger.kernel.org> # v5.4+ Reported-by: Ilya Leoshkevich <iii@linux.ibm.com> Tested-by: Ilya Leoshkevich <iii@linux.ibm.com> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> |
||
|---|---|---|
| .. | ||
| cmm.c | ||
| dump_pagetables.c | ||
| extmem.c | ||
| fault.c | ||
| gmap.c | ||
| hugetlbpage.c | ||
| init.c | ||
| kasan_init.c | ||
| maccess.c | ||
| Makefile | ||
| mmap.c | ||
| page-states.c | ||
| pageattr.c | ||
| pgalloc.c | ||
| pgtable.c | ||
| vmem.c | ||