Hi, > Hi, > > > On Thu, Jul 17, 2025 at 08:13:33AM +0800, Wang Yugui wrote: > > > Hi, > > > > > > There seems a deadloop(?) when mkfs.xfs -o rtdev. > > > > > > # mkfs.xfs -r rtdev=/dev/disk/by-id/ata-MZ7KM1T6HAJM00D3_S2CXNAAH600026 /dev/d > > > isk/by-id/scsi-SHITACHI_HUSMH842_CLAR100_0LX0JWVA -f > > > meta-data=/dev/disk/by-id/scsi-SHITACHI_HUSMH842_CLAR100_0LX0JWVA isize=512 agcount=20, agsize=1221072 blks > > > = sectsz=4096 attr=2, projid32bit=1 > > > = crc=1 finobt=1, sparse=1, rmapbt=0 > > > = reflink=0 bigtime=1 inobtcount=1 nrext64=1 > > > = exchange=0 > > > data = bsize=4096 blocks=24421440, imaxpct=25 > > > = sunit=0 swidth=0 blks > > > naming =version 2 bsize=4096 ascii-ci=0, ftype=1, parent=0 > > > log =internal log bsize=4096 blocks=41799, version=2 > > > = sectsz=4096 sunit=1 blks, lazy-count=1 > > > realtime =/dev/disk/by-id/ata-MZ7KM1T6HAJM00D3_S2CXNAAH600026 extsz=4096 blocks=390703446, rtextents=390703446 > > > Discarding blocks...Done. > > > Discarding blocks...Done. > > > > > > It did not fishish after 10 mins. > > > > > > # pstack 5785 > > > #0 0x00007f8df5efc01a in pread64 () from /lib64/libc.so.6 > > > #1 0x0000557b7bbfe9c3 in __read_buf.constprop.0 () > > > #2 0x0000557b7bbc3030 in libxfs_buf_read_map () > > > #3 0x0000557b7bbfe1ae in libxfs_trans_read_buf_map.constprop () > > > #4 0x0000557b7bbee7ef in xfs_rtbuf_get () > > > #5 0x0000557b7bbf03d8 in libxfs_rtfree_extent () > > > #6 0x0000557b7bbbb322 in parseproto.lto_priv () > > > #7 0x0000557b7bbb7643 in main () > > > > > > And, > > > 1) more chance happen when kernel 6.12.36, but yet not happen when kernel 6.6.93. > > > 2) it happen on both xfsprogs-6.11.0 and xfsprogs-6.4. > > > > You /could/ strace the mkfs process to see if it's really stuck, or just > > issuing IOs really slowly. > > Today the mkfs.xfs with rtdev all finished in 110s-160s on kernel 6.6.93/6.12.38. > > the result of strace show that pread64() with 4K size so it is just slow. > > pread64(3, "\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377"..., 4096, 868352) = 4096 > pread64(3, "\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377"..., 4096, 864256) = 4096 > pread64(3, "\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377"..., 4096, 860160) = 4096 > pread64(3, "\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377"..., 4096, 856064) = 4096 > pread64(3, "\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377"..., 4096, 851968) = 4096 > the offset of pread64() is in DECE order, not in ASCE order , so the readahead does not help too. Best Regards Wang Yugui (wangyugui@xxxxxxxxxxxx) 2025/07/18 > Thanks a lot. > > Best Regards > Wang Yugui (wangyugui@xxxxxxxxxxxx) > 2025/07/18 >
