LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
* [PATCH 0/2] mm: Fix NFS swapfiles and use DIO read for swapfiles
@ 2021-08-12 11:57 David Howells
  2021-08-12 11:57 ` [PATCH 1/2] nfs: Fix write to swapfile failure due to generic_write_checks() David Howells
                   ` (2 more replies)
  0 siblings, 3 replies; 17+ messages in thread
From: David Howells @ 2021-08-12 11:57 UTC (permalink / raw)
  To: willy
  Cc: dhowells, trond.myklebust, darrick.wong, hch, jlayton, sfrench,
	torvalds, linux-nfs, linux-mm, linux-fsdevel, linux-kernel


Hi Willy, Trond,

Here's a change to make reads from the swapfile use async DIO rather than
readpage(), as requested by Willy.

Whilst trying to make this work, I found that NFS's support for swapfiles
seems to have been non-functional since Aug 2019 (I think), so the first
patch fixes that.  Question is: do we actually *want* to keep this
functionality, given that it seems that no one's tested it with an upstream
kernel in the last couple of years?

I tested this using the procedure and program outlined in the first patch.

I also encountered occasional instances of the following warning, so I'm
wondering if there's a scheduling problem somewhere:

BUG: workqueue lockup - pool cpus=0-3 flags=0x5 nice=0 stuck for 34s!
Showing busy workqueues and worker pools:
workqueue events: flags=0x0
  pwq 6: cpus=3 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
    in-flight: 1565:fill_page_cache_func
workqueue events_highpri: flags=0x10
  pwq 3: cpus=1 node=0 flags=0x1 nice=-20 active=1/256 refcnt=2
    in-flight: 1547:fill_page_cache_func
  pwq 1: cpus=0 node=0 flags=0x0 nice=-20 active=1/256 refcnt=2
    in-flight: 1811:fill_page_cache_func
workqueue events_unbound: flags=0x2
  pwq 8: cpus=0-3 flags=0x5 nice=0 active=3/512 refcnt=5
    pending: fsnotify_connector_destroy_workfn, fsnotify_mark_destroy_workfn, cleanup_offline_cgwbs_workfn
workqueue events_power_efficient: flags=0x82
  pwq 8: cpus=0-3 flags=0x5 nice=0 active=4/256 refcnt=6
    pending: neigh_periodic_work, neigh_periodic_work, check_lifetime, do_cache_clean
workqueue writeback: flags=0x4a
  pwq 8: cpus=0-3 flags=0x5 nice=0 active=1/256 refcnt=4
    in-flight: 433(RESCUER):wb_workfn
workqueue rpciod: flags=0xa
  pwq 8: cpus=0-3 flags=0x5 nice=0 active=38/256 refcnt=40
    in-flight: 7:rpc_async_schedule, 1609:rpc_async_schedule, 1610:rpc_async_schedule, 912:rpc_async_schedule, 1613:rpc_async_schedule, 1631:rpc_async_schedule, 34:rpc_async_schedule, 44:rpc_async_schedule
    pending: rpc_async_schedule, rpc_async_schedule, rpc_async_schedule, rpc_async_schedule, rpc_async_schedule, rpc_async_schedule, rpc_async_schedule, rpc_async_schedule, rpc_async_schedule, rpc_async_schedule, rpc_async_schedule, rpc_async_schedule, rpc_async_schedule, rpc_async_schedule, rpc_async_schedule, rpc_async_schedule, rpc_async_schedule, rpc_async_schedule, rpc_async_schedule, rpc_async_schedule, rpc_async_schedule, rpc_async_schedule, rpc_async_schedule, rpc_async_schedule, rpc_async_schedule, rpc_async_schedule, rpc_async_schedule, rpc_async_schedule, rpc_async_schedule, rpc_async_schedule
workqueue ext4-rsv-conversion: flags=0x2000a
pool 1: cpus=0 node=0 flags=0x0 nice=-20 hung=59s workers=2 idle: 6
pool 3: cpus=1 node=0 flags=0x1 nice=-20 hung=43s workers=2 manager: 20
pool 6: cpus=3 node=0 flags=0x0 nice=0 hung=0s workers=3 idle: 498 29
pool 8: cpus=0-3 flags=0x5 nice=0 hung=34s workers=9 manager: 1623
pool 9: cpus=0-3 flags=0x5 nice=-20 hung=0s workers=2 manager: 5224 idle: 859

Note that this is due to DIO writes to NFS only, as far as I can tell, and
that no reads had happened yet.

David
---
David Howells (2):
      nfs: Fix write to swapfile failure due to generic_write_checks()
      mm: Make swap_readpage() for SWP_FS_OPS use ->direct_IO() not ->readpage()


 mm/page_io.c | 73 +++++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 67 insertions(+), 6 deletions(-)



^ permalink raw reply	[flat|nested] 17+ messages in thread

end of thread, other threads:[~2021-08-13  6:54 UTC | newest]

Thread overview: 17+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-08-12 11:57 [PATCH 0/2] mm: Fix NFS swapfiles and use DIO read for swapfiles David Howells
2021-08-12 11:57 ` [PATCH 1/2] nfs: Fix write to swapfile failure due to generic_write_checks() David Howells
2021-08-12 11:57 ` [PATCH 2/2] mm: Make swap_readpage() for SWP_FS_OPS use ->direct_IO() not ->readpage() David Howells
2021-08-12 12:21   ` Christoph Hellwig
2021-08-12 12:57   ` David Howells
2021-08-12 15:39     ` Matthew Wilcox
2021-08-12 17:02       ` Christoph Hellwig
2021-08-12 17:48         ` Darrick J. Wong
2021-08-12 18:14           ` Matthew Wilcox
2021-08-12 20:13             ` Theodore Ts'o
2021-08-13  6:54           ` Christoph Hellwig
2021-08-12 13:00   ` Matthew Wilcox
2021-08-12 13:23   ` David Howells
2021-08-12 13:37   ` David Howells
2021-08-12 13:50     ` Matthew Wilcox
2021-08-12 14:16     ` David Howells
2021-08-12 12:18 ` [PATCH 0/2] mm: Fix NFS swapfiles and use DIO read for swapfiles Christoph Hellwig

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).