* Re: [RFC PATCH 2/2] NFSD: Add asynchronous write throttling support
[not found] <20251219141105.1247093-3-cel@kernel.org>
@ 2025-12-20 15:34 ` kernel test robot
2025-12-22 23:47 ` kernel test robot
1 sibling, 0 replies; 2+ messages in thread
From: kernel test robot @ 2025-12-20 15:34 UTC (permalink / raw)
To: Chuck Lever; +Cc: llvm, oe-kbuild-all
Hi Chuck,
[This is a private test report for your RFC patch.]
kernel test robot noticed the following build errors:
[auto build test ERROR on brauner-vfs/vfs.all]
[also build test ERROR on next-20251219]
[cannot apply to linus/master v6.16-rc1]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Chuck-Lever/NFSD-Add-aggressive-write-throttling-control/20251219-221859
base: https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git vfs.all
patch link: https://lore.kernel.org/r/20251219141105.1247093-3-cel%40kernel.org
patch subject: [RFC PATCH 2/2] NFSD: Add asynchronous write throttling support
config: x86_64-kexec (https://download.01.org/0day-ci/archive/20251220/202512201657.c3KKm6Kh-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251220/202512201657.c3KKm6Kh-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202512201657.c3KKm6Kh-lkp@intel.com/
All errors (new ones prefixed by >>):
>> fs/nfsd/vfs.c:1490:4: error: 'break' statement not in loop or switch statement
1490 | break;
| ^
1 error generated.
vim +/break +1490 fs/nfsd/vfs.c
1389
1390 /**
1391 * nfsd_vfs_write - write data to an already-open file
1392 * @rqstp: RPC execution context
1393 * @fhp: File handle of file to write into
1394 * @nf: An open file matching @fhp
1395 * @offset: Byte offset of start
1396 * @payload: xdr_buf containing the write payload
1397 * @cnt: IN: number of bytes to write, OUT: number of bytes actually written
1398 * @stable: An NFS stable_how value
1399 * @verf: NFS WRITE verifier
1400 *
1401 * Upon return, caller must invoke fh_put on @fhp.
1402 *
1403 * Return values:
1404 * An nfsstat value in network byte order.
1405 */
1406 __be32
1407 nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp,
1408 struct nfsd_file *nf, loff_t offset,
1409 const struct xdr_buf *payload, unsigned long *cnt,
1410 int stable, __be32 *verf)
1411 {
1412 struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
1413 struct file *file = nf->nf_file;
1414 struct super_block *sb = file_inode(file)->i_sb;
1415 struct kiocb kiocb;
1416 struct svc_export *exp;
1417 struct iov_iter iter;
1418 errseq_t since;
1419 __be32 nfserr;
1420 int host_err;
1421 unsigned long exp_op_flags = 0;
1422 unsigned int pflags = current->flags;
1423 bool restore_flags = false;
1424 unsigned int nvecs;
1425 int saved_nr_dirtied_pause = 0;
1426 bool throttle_adjusted = false;
1427
1428 trace_nfsd_write_opened(rqstp, fhp, offset, *cnt);
1429
1430 if (sb->s_export_op)
1431 exp_op_flags = sb->s_export_op->flags;
1432
1433 if (test_bit(RQ_LOCAL, &rqstp->rq_flags) &&
1434 !(exp_op_flags & EXPORT_OP_REMOTE_FS)) {
1435 /*
1436 * We want throttling in balance_dirty_pages()
1437 * and shrink_inactive_list() to only consider
1438 * the backingdev we are writing to, so that nfs to
1439 * localhost doesn't cause nfsd to lock up due to all
1440 * the client's dirty pages or its congested queue.
1441 */
1442 current->flags |= PF_LOCAL_THROTTLE;
1443 restore_flags = true;
1444 }
1445
1446 exp = fhp->fh_export;
1447
1448 /*
1449 * If aggressive write throttling is enabled, reduce the per-task
1450 * dirty page limit to throttle NFSD writes more aggressively.
1451 * This helps prevent memory exhaustion when fast network clients
1452 * overwhelm slow storage.
1453 */
1454 if (nfsd_aggressive_write_throttle) {
1455 saved_nr_dirtied_pause = current->nr_dirtied_pause;
1456 current->nr_dirtied_pause = NFSD_AGGRESSIVE_DIRTY_LIMIT;
1457 throttle_adjusted = true;
1458 }
1459
1460 if (!EX_ISSYNC(exp))
1461 stable = NFS_UNSTABLE;
1462 init_sync_kiocb(&kiocb, file);
1463 kiocb.ki_pos = offset;
1464 if (likely(!fhp->fh_use_wgather)) {
1465 switch (stable) {
1466 case NFS_FILE_SYNC:
1467 /* persist data and timestamps */
1468 kiocb.ki_flags |= IOCB_DSYNC | IOCB_SYNC;
1469 break;
1470 case NFS_DATA_SYNC:
1471 /* persist data only */
1472 kiocb.ki_flags |= IOCB_DSYNC;
1473 break;
1474 }
1475 }
1476
1477 /*
1478 * If async throttling is enabled, check memory pressure
1479 * before attempting buffered writes. Return -EAGAIN if
1480 * the system is low on memory, allowing NFSD to return
1481 * an NFS error code asking the client to retry later.
1482 *
1483 * Skip this for NFSv2 since it lacks NFSERR_JUKEBOX.
1484 */
1485 if (nfsd_async_write_throttle && rqstp->rq_vers >= 3) {
1486 host_err =
1487 balance_dirty_pages_ratelimited_flags(file->f_mapping,
1488 BDP_ASYNC);
1489 if (host_err == -EAGAIN)
> 1490 break;
1491 }
1492
1493 nvecs = xdr_buf_to_bvec(rqstp->rq_bvec, rqstp->rq_maxpages, payload);
1494
1495 since = READ_ONCE(file->f_wb_err);
1496 if (verf)
1497 nfsd_copy_write_verifier(verf, nn);
1498
1499 switch (nfsd_io_cache_write) {
1500 case NFSD_IO_DIRECT:
1501 host_err = nfsd_direct_write(rqstp, fhp, nf, nvecs,
1502 cnt, &kiocb);
1503 break;
1504 case NFSD_IO_DONTCACHE:
1505 if (file->f_op->fop_flags & FOP_DONTCACHE)
1506 kiocb.ki_flags |= IOCB_DONTCACHE;
1507 fallthrough;
1508 case NFSD_IO_BUFFERED:
1509 iov_iter_bvec(&iter, ITER_SOURCE, rqstp->rq_bvec, nvecs, *cnt);
1510 host_err = vfs_iocb_iter_write(file, &kiocb, &iter);
1511 if (host_err < 0)
1512 break;
1513 *cnt = host_err;
1514 break;
1515 }
1516 if (host_err < 0) {
1517 commit_reset_write_verifier(nn, rqstp, host_err);
1518 goto out_nfserr;
1519 }
1520 nfsd_stats_io_write_add(nn, exp, *cnt);
1521 fsnotify_modify(file);
1522 host_err = filemap_check_wb_err(file->f_mapping, since);
1523 if (host_err < 0)
1524 goto out_nfserr;
1525
1526 if (stable && fhp->fh_use_wgather) {
1527 host_err = wait_for_concurrent_writes(file);
1528 if (host_err < 0)
1529 commit_reset_write_verifier(nn, rqstp, host_err);
1530 }
1531
1532 out_nfserr:
1533 if (host_err >= 0) {
1534 trace_nfsd_write_io_done(rqstp, fhp, offset, *cnt);
1535 nfserr = nfs_ok;
1536 } else {
1537 trace_nfsd_write_err(rqstp, fhp, offset, host_err);
1538 nfserr = nfserrno(host_err);
1539 }
1540 if (throttle_adjusted)
1541 current->nr_dirtied_pause = saved_nr_dirtied_pause;
1542 if (restore_flags)
1543 current_restore_flags(pflags, PF_LOCAL_THROTTLE);
1544 return nfserr;
1545 }
1546
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
^ permalink raw reply [flat|nested] 2+ messages in thread* Re: [RFC PATCH 2/2] NFSD: Add asynchronous write throttling support
[not found] <20251219141105.1247093-3-cel@kernel.org>
2025-12-20 15:34 ` [RFC PATCH 2/2] NFSD: Add asynchronous write throttling support kernel test robot
@ 2025-12-22 23:47 ` kernel test robot
1 sibling, 0 replies; 2+ messages in thread
From: kernel test robot @ 2025-12-22 23:47 UTC (permalink / raw)
To: Chuck Lever; +Cc: llvm, oe-kbuild-all
Hi Chuck,
[This is a private test report for your RFC patch.]
kernel test robot noticed the following build errors:
[auto build test ERROR on brauner-vfs/vfs.all]
[also build test ERROR on linus/master v6.19-rc2 next-20251219]
[cannot apply to hch-configfs/for-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Chuck-Lever/NFSD-Add-aggressive-write-throttling-control/20251219-221859
base: https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git vfs.all
patch link: https://lore.kernel.org/r/20251219141105.1247093-3-cel%40kernel.org
patch subject: [RFC PATCH 2/2] NFSD: Add asynchronous write throttling support
config: loongarch-defconfig (https://download.01.org/0day-ci/archive/20251223/202512230750.htK4fXlz-lkp@intel.com/config)
compiler: clang version 19.1.7 (https://github.com/llvm/llvm-project cd708029e0b2869e80abe31ddb175f7c35361f90)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251223/202512230750.htK4fXlz-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202512230750.htK4fXlz-lkp@intel.com/
All errors (new ones prefixed by >>):
>> fs/nfsd/vfs.c:1490:4: error: 'break' statement not in loop or switch statement
1490 | break;
| ^
1 error generated.
vim +/break +1490 fs/nfsd/vfs.c
1389
1390 /**
1391 * nfsd_vfs_write - write data to an already-open file
1392 * @rqstp: RPC execution context
1393 * @fhp: File handle of file to write into
1394 * @nf: An open file matching @fhp
1395 * @offset: Byte offset of start
1396 * @payload: xdr_buf containing the write payload
1397 * @cnt: IN: number of bytes to write, OUT: number of bytes actually written
1398 * @stable: An NFS stable_how value
1399 * @verf: NFS WRITE verifier
1400 *
1401 * Upon return, caller must invoke fh_put on @fhp.
1402 *
1403 * Return values:
1404 * An nfsstat value in network byte order.
1405 */
1406 __be32
1407 nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp,
1408 struct nfsd_file *nf, loff_t offset,
1409 const struct xdr_buf *payload, unsigned long *cnt,
1410 int stable, __be32 *verf)
1411 {
1412 struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
1413 struct file *file = nf->nf_file;
1414 struct super_block *sb = file_inode(file)->i_sb;
1415 struct kiocb kiocb;
1416 struct svc_export *exp;
1417 struct iov_iter iter;
1418 errseq_t since;
1419 __be32 nfserr;
1420 int host_err;
1421 unsigned long exp_op_flags = 0;
1422 unsigned int pflags = current->flags;
1423 bool restore_flags = false;
1424 unsigned int nvecs;
1425 int saved_nr_dirtied_pause = 0;
1426 bool throttle_adjusted = false;
1427
1428 trace_nfsd_write_opened(rqstp, fhp, offset, *cnt);
1429
1430 if (sb->s_export_op)
1431 exp_op_flags = sb->s_export_op->flags;
1432
1433 if (test_bit(RQ_LOCAL, &rqstp->rq_flags) &&
1434 !(exp_op_flags & EXPORT_OP_REMOTE_FS)) {
1435 /*
1436 * We want throttling in balance_dirty_pages()
1437 * and shrink_inactive_list() to only consider
1438 * the backingdev we are writing to, so that nfs to
1439 * localhost doesn't cause nfsd to lock up due to all
1440 * the client's dirty pages or its congested queue.
1441 */
1442 current->flags |= PF_LOCAL_THROTTLE;
1443 restore_flags = true;
1444 }
1445
1446 exp = fhp->fh_export;
1447
1448 /*
1449 * If aggressive write throttling is enabled, reduce the per-task
1450 * dirty page limit to throttle NFSD writes more aggressively.
1451 * This helps prevent memory exhaustion when fast network clients
1452 * overwhelm slow storage.
1453 */
1454 if (nfsd_aggressive_write_throttle) {
1455 saved_nr_dirtied_pause = current->nr_dirtied_pause;
1456 current->nr_dirtied_pause = NFSD_AGGRESSIVE_DIRTY_LIMIT;
1457 throttle_adjusted = true;
1458 }
1459
1460 if (!EX_ISSYNC(exp))
1461 stable = NFS_UNSTABLE;
1462 init_sync_kiocb(&kiocb, file);
1463 kiocb.ki_pos = offset;
1464 if (likely(!fhp->fh_use_wgather)) {
1465 switch (stable) {
1466 case NFS_FILE_SYNC:
1467 /* persist data and timestamps */
1468 kiocb.ki_flags |= IOCB_DSYNC | IOCB_SYNC;
1469 break;
1470 case NFS_DATA_SYNC:
1471 /* persist data only */
1472 kiocb.ki_flags |= IOCB_DSYNC;
1473 break;
1474 }
1475 }
1476
1477 /*
1478 * If async throttling is enabled, check memory pressure
1479 * before attempting buffered writes. Return -EAGAIN if
1480 * the system is low on memory, allowing NFSD to return
1481 * an NFS error code asking the client to retry later.
1482 *
1483 * Skip this for NFSv2 since it lacks NFSERR_JUKEBOX.
1484 */
1485 if (nfsd_async_write_throttle && rqstp->rq_vers >= 3) {
1486 host_err =
1487 balance_dirty_pages_ratelimited_flags(file->f_mapping,
1488 BDP_ASYNC);
1489 if (host_err == -EAGAIN)
> 1490 break;
1491 }
1492
1493 nvecs = xdr_buf_to_bvec(rqstp->rq_bvec, rqstp->rq_maxpages, payload);
1494
1495 since = READ_ONCE(file->f_wb_err);
1496 if (verf)
1497 nfsd_copy_write_verifier(verf, nn);
1498
1499 switch (nfsd_io_cache_write) {
1500 case NFSD_IO_DIRECT:
1501 host_err = nfsd_direct_write(rqstp, fhp, nf, nvecs,
1502 cnt, &kiocb);
1503 break;
1504 case NFSD_IO_DONTCACHE:
1505 if (file->f_op->fop_flags & FOP_DONTCACHE)
1506 kiocb.ki_flags |= IOCB_DONTCACHE;
1507 fallthrough;
1508 case NFSD_IO_BUFFERED:
1509 iov_iter_bvec(&iter, ITER_SOURCE, rqstp->rq_bvec, nvecs, *cnt);
1510 host_err = vfs_iocb_iter_write(file, &kiocb, &iter);
1511 if (host_err < 0)
1512 break;
1513 *cnt = host_err;
1514 break;
1515 }
1516 if (host_err < 0) {
1517 commit_reset_write_verifier(nn, rqstp, host_err);
1518 goto out_nfserr;
1519 }
1520 nfsd_stats_io_write_add(nn, exp, *cnt);
1521 fsnotify_modify(file);
1522 host_err = filemap_check_wb_err(file->f_mapping, since);
1523 if (host_err < 0)
1524 goto out_nfserr;
1525
1526 if (stable && fhp->fh_use_wgather) {
1527 host_err = wait_for_concurrent_writes(file);
1528 if (host_err < 0)
1529 commit_reset_write_verifier(nn, rqstp, host_err);
1530 }
1531
1532 out_nfserr:
1533 if (host_err >= 0) {
1534 trace_nfsd_write_io_done(rqstp, fhp, offset, *cnt);
1535 nfserr = nfs_ok;
1536 } else {
1537 trace_nfsd_write_err(rqstp, fhp, offset, host_err);
1538 nfserr = nfserrno(host_err);
1539 }
1540 if (throttle_adjusted)
1541 current->nr_dirtied_pause = saved_nr_dirtied_pause;
1542 if (restore_flags)
1543 current_restore_flags(pflags, PF_LOCAL_THROTTLE);
1544 return nfserr;
1545 }
1546
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
^ permalink raw reply [flat|nested] 2+ messages in thread