Eric Sandeen wrote: > Eric Sandeen wrote: > >> The remaining issue may be xfs+4kstacks+complicated/deep IO stacks on >> x86. Honestly I've never much liked 4kstacks... layered filesystems >> coming down the pipe (ecryptfs, unionfs) may well have trouble too. >> I'd prefer to see the stack size boot-time selectable, maybe - or >> perhaps disallow xfs (or issue a stern warning) on x86 boxes? (x86_64 & >> ia64, with sane stack size, work fine in this regard). > > I can confirm that xfs on 4KSTACKS over lvm is still a problem. > > Basic functionality is fine, but I can't make it through all of xfsqa > w/o a stack overflow. Even just mounting with -o quota gets us pretty > close to the edge: > > mount used greatest stack depth: 180 bytes left > > I'll look at some of the bigger offenders if I have any spare time in > the evenings. It's the callchains, too though, not just the individual > functions that come into play. Ok, some good news on this front. With a handful of changes, I got these stack reductions: xfs_alloc_file_space [xfs]: 184 176 : -8 xfs_bmap_adjacent [xfs]: 120 136 : +16 xfs_bmapi [xfs]: 276 268 : -8 xfs_bunmapi [xfs]: 200 172 : -28 xfs_create [xfs]: 116 100 : -16 xfs_free_file_space [xfs]: 200 132 : -68 xfs_getbmap [xfs]: 200 204 : +4 xfs_iomap_write_direct [xfs]: 180 168 : -12 xfs_link [xfs]: 96 88 : -8 xfs_mkdir [xfs]: 116 96 : -20 xfs_mountfs [xfs]: 200 152 : -48 xfs_qm_dqusage_adjust [xfs]: 52 48 : -4 xfs_qm_vop_chown_reserve [xfs]: 48 44 : -4 xfs_read [xfs]: 72 48 : -24 xfs_remove [xfs]: 96 84 : -12 xfs_rename [xfs]: 144 136 : -8 xfs_rmdir [xfs]: 92 76 : -16 xfs_setattr [xfs]: 132 116 : -16 xfs_splice_read [xfs]: 36 16 : -20 xfs_splice_write [xfs]: 56 36 : -20 xfs_unmount [xfs]: 52 4 : -48 xfs_write [xfs]: 144 124 : -20 ---------------------- Functions increased: 2 Functions decreased: 20 Net change: -388 and I can now survive xfsqa over lvm on 4KSTACKS. I still get within spitting distance of the end of the stack though. :) I've put the stack-reducing changes & a few bugfixes into kernel-2.6.23-0.133.rc3.git6.fc8, building now. -Eric -- fedora-devel-list mailing list fedora-devel-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/fedora-devel-list
