[merged mm-hotfixes-stable] mm-zswap-fix-writeback-shinker-gfp_noio-gfp_nofs-recursion.patch removed from -mm tree

[merged mm-hotfixes-stable] mm-zswap-fix-writeback-shinker-gfp_noio-gfp_nofs-recursion.patch removed from -mm tree

[Andrew Morton]

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The quilt patch titled
     Subject: mm: zswap: fix writeback shinker GFP_NOIO/GFP_NOFS recursion
has been removed from the -mm tree.  Its filename was
     mm-zswap-fix-writeback-shinker-gfp_noio-gfp_nofs-recursion.patch

This patch was dropped because it was merged into the mm-hotfixes-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Johannes Weiner <hannes@cmpxchg.org>
Subject: mm: zswap: fix writeback shinker GFP_NOIO/GFP_NOFS recursion
Date: Thu, 21 Mar 2024 14:25:32 -0400

Kent forwards this bug report of zswap re-entering the block layer
from an IO request allocation and locking up:

[10264.128242] sysrq: Show Blocked State
[10264.128268] task:kworker/20:0H   state:D stack:0     pid:143   tgid:143   ppid:2      flags:0x00004000
[10264.128271] Workqueue: bcachefs_io btree_write_submit [bcachefs]
[10264.128295] Call Trace:
[10264.128295]  <TASK>
[10264.128297]  __schedule+0x3e6/0x1520
[10264.128303]  schedule+0x32/0xd0
[10264.128304]  schedule_timeout+0x98/0x160
[10264.128308]  io_schedule_timeout+0x50/0x80
[10264.128309]  wait_for_completion_io_timeout+0x7f/0x180
[10264.128310]  submit_bio_wait+0x78/0xb0
[10264.128313]  swap_writepage_bdev_sync+0xf6/0x150
[10264.128317]  zswap_writeback_entry+0xf2/0x180
[10264.128319]  shrink_memcg_cb+0xe7/0x2f0
[10264.128322]  __list_lru_walk_one+0xb9/0x1d0
[10264.128325]  list_lru_walk_one+0x5d/0x90
[10264.128326]  zswap_shrinker_scan+0xc4/0x130
[10264.128327]  do_shrink_slab+0x13f/0x360
[10264.128328]  shrink_slab+0x28e/0x3c0
[10264.128329]  shrink_one+0x123/0x1b0
[10264.128331]  shrink_node+0x97e/0xbc0
[10264.128332]  do_try_to_free_pages+0xe7/0x5b0
[10264.128333]  try_to_free_pages+0xe1/0x200
[10264.128334]  __alloc_pages_slowpath.constprop.0+0x343/0xde0
[10264.128337]  __alloc_pages+0x32d/0x350
[10264.128338]  allocate_slab+0x400/0x460
[10264.128339]  ___slab_alloc+0x40d/0xa40
[10264.128345]  kmem_cache_alloc+0x2e7/0x330
[10264.128348]  mempool_alloc+0x86/0x1b0
[10264.128349]  bio_alloc_bioset+0x200/0x4f0
[10264.128352]  bio_alloc_clone+0x23/0x60
[10264.128354]  alloc_io+0x26/0xf0 [dm_mod 7e9e6b44df4927f93fb3e4b5c782767396f58382]
[10264.128361]  dm_submit_bio+0xb8/0x580 [dm_mod 7e9e6b44df4927f93fb3e4b5c782767396f58382]
[10264.128366]  __submit_bio+0xb0/0x170
[10264.128367]  submit_bio_noacct_nocheck+0x159/0x370
[10264.128368]  bch2_submit_wbio_replicas+0x21c/0x3a0 [bcachefs 85f1b9a7a824f272eff794653a06dde1a94439f2]
[10264.128391]  btree_write_submit+0x1cf/0x220 [bcachefs 85f1b9a7a824f272eff794653a06dde1a94439f2]
[10264.128406]  process_one_work+0x178/0x350
[10264.128408]  worker_thread+0x30f/0x450
[10264.128409]  kthread+0xe5/0x120

The zswap shrinker resumes the swap_writepage()s that were intercepted
by the zswap store. This will enter the block layer, and may even
enter the filesystem depending on the swap backing file.

Make it respect GFP_NOIO and GFP_NOFS.

Link: https://lore.kernel.org/linux-mm/rc4pk2r42oyvjo4dc62z6sovquyllq56i5cdgcaqbd7wy3hfzr@n4nbxido3fme/
Link: https://lkml.kernel.org/r/20240321182532.60000-1-hannes@cmpxchg.org
Fixes: b5ba474f3f51 ("zswap: shrink zswap pool based on memory pressure")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Kent Overstreet <kent.overstreet@linux.dev>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Reported-by: Jérôme Poulin <jeromepoulin@gmail.com>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Reviewed-by: Chengming Zhou <chengming.zhou@linux.dev>
Cc: stable@vger.kernel.org	[v6.8]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/zswap.c |    8 ++++++++
 1 file changed, 8 insertions(+)

--- a/mm/zswap.c~mm-zswap-fix-writeback-shinker-gfp_noio-gfp_nofs-recursion
+++ a/mm/zswap.c
@@ -1323,6 +1323,14 @@ static unsigned long zswap_shrinker_coun
 	if (!zswap_shrinker_enabled || !mem_cgroup_zswap_writeback_enabled(memcg))
 		return 0;
 
+	/*
+	 * The shrinker resumes swap writeback, which will enter block
+	 * and may enter fs. XXX: Harmonize with vmscan.c __GFP_FS
+	 * rules (may_enter_fs()), which apply on a per-folio basis.
+	 */
+	if (!gfp_has_io_fs(sc->gfp_mask))
+		return 0;
+
 #ifdef CONFIG_MEMCG_KMEM
 	mem_cgroup_flush_stats(memcg);
 	nr_backing = memcg_page_state(memcg, MEMCG_ZSWAP_B) >> PAGE_SHIFT;
_

Patches currently in -mm which might be from hannes@cmpxchg.org are

mm-zswap-optimize-zswap-pool-size-tracking.patch
mm-zpool-return-pool-size-in-pages.patch
mm-page_alloc-remove-pcppage-migratetype-caching.patch
mm-page_alloc-optimize-free_unref_folios.patch
mm-page_alloc-fix-up-block-types-when-merging-compatible-blocks.patch
mm-page_alloc-move-free-pages-when-converting-block-during-isolation.patch
mm-page_alloc-fix-move_freepages_block-range-error.patch
mm-page_alloc-fix-freelist-movement-during-block-conversion.patch
mm-page_alloc-close-migratetype-race-between-freeing-and-stealing.patch
mm-page_isolation-prepare-for-hygienic-freelists.patch
mm-page_isolation-prepare-for-hygienic-freelists-fix.patch
mm-page_alloc-consolidate-free-page-accounting.patch