4be55565fe
Unless __GFP_IO and __GFP_FS are removed from the file mapping gfp mask we may enter memory reclaim during IO. In this case shrink_slab() entered another file system which is notoriously hungry for stack. This additional stack usage may cause a stack overflow. This patch removes __GFP_IO and __GFP_FS from the mapping gfp mask of each file during vn_open() to avoid any reclaim in the vn_rdwr() IO path. The original mask is then restored at vn_close() time. Hats off to the loop driver which does something similiar for the same reason. [...] shrink_slab+0xdc/0x153 try_to_free_pages+0x1da/0x2d7 __alloc_pages+0x1d7/0x2da do_generic_mapping_read+0x2c9/0x36f file_read_actor+0x0/0x145 __generic_file_aio_read+0x14f/0x19b generic_file_aio_read+0x34/0x39 do_sync_read+0xc7/0x104 vfs_read+0xcb/0x171 :spl:vn_rdwr+0x2b8/0x402 :zfs:vdev_file_io_start+0xad/0xe1 [...] Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> |
||
|---|---|---|
| .. | ||
| spl | ||
| splat | ||
| .gitignore | ||
| Makefile.in | ||