The patch titled
Subject: mm/truncate: batch-clear shadow entries
has been added to the -mm mm-unstable branch. Its filename is
mm-truncate-batch-clear-shadow-entries.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-truncate-batch-clear-shadow-entries.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Yu Zhao <yuzhao@xxxxxxxxxx>
Subject: mm/truncate: batch-clear shadow entries
Date: Mon, 8 Jul 2024 15:27:53 -0600
Make clear_shadow_entry() clear shadow entries in `struct folio_batch` so
that it can reduce contention on i_lock and i_pages locks, e.g.,
watchdog: BUG: soft lockup - CPU#29 stuck for 11s! [fio:2701649]
clear_shadow_entry+0x3d/0x100
mapping_try_invalidate+0x117/0x1d0
invalidate_mapping_pages+0x10/0x20
invalidate_bdev+0x3c/0x50
blkdev_common_ioctl+0x5f7/0xa90
blkdev_ioctl+0x109/0x270
Link: https://lkml.kernel.org/r/20240708212753.3120511-1-yuzhao@xxxxxxxxxx
Reported-by: Bharata B Rao <bharata@xxxxxxx>
Closes: https://lore.kernel.org/d2841226-e27b-4d3d-a578-63587a3aa4f3@xxxxxxx/
Signed-off-by: Yu Zhao <yuzhao@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/truncate.c | 67 +++++++++++++++++++++---------------------------
1 file changed, 30 insertions(+), 37 deletions(-)
--- a/mm/truncate.c~mm-truncate-batch-clear-shadow-entries
+++ a/mm/truncate.c
@@ -39,12 +39,24 @@ static inline void __clear_shadow_entry(
xas_store(&xas, NULL);
}
-static void clear_shadow_entry(struct address_space *mapping, pgoff_t index,
- void *entry)
+static void clear_shadow_entry(struct address_space *mapping,
+ struct folio_batch *fbatch, pgoff_t *indices)
{
+ int i;
+
+ if (shmem_mapping(mapping) || dax_mapping(mapping))
+ return;
+
spin_lock(&mapping->host->i_lock);
xa_lock_irq(&mapping->i_pages);
- __clear_shadow_entry(mapping, index, entry);
+
+ for (i = 0; i < folio_batch_count(fbatch); i++) {
+ struct folio *folio = fbatch->folios[i];
+
+ if (xa_is_value(folio))
+ __clear_shadow_entry(mapping, indices[i], folio);
+ }
+
xa_unlock_irq(&mapping->i_pages);
if (mapping_shrinkable(mapping))
inode_add_lru(mapping->host);
@@ -105,36 +117,6 @@ static void truncate_folio_batch_excepti
fbatch->nr = j;
}
-/*
- * Invalidate exceptional entry if easily possible. This handles exceptional
- * entries for invalidate_inode_pages().
- */
-static int invalidate_exceptional_entry(struct address_space *mapping,
- pgoff_t index, void *entry)
-{
- /* Handled by shmem itself, or for DAX we do nothing. */
- if (shmem_mapping(mapping) || dax_mapping(mapping))
- return 1;
- clear_shadow_entry(mapping, index, entry);
- return 1;
-}
-
-/*
- * Invalidate exceptional entry if clean. This handles exceptional entries for
- * invalidate_inode_pages2() so for DAX it evicts only clean entries.
- */
-static int invalidate_exceptional_entry2(struct address_space *mapping,
- pgoff_t index, void *entry)
-{
- /* Handled by shmem itself */
- if (shmem_mapping(mapping))
- return 1;
- if (dax_mapping(mapping))
- return dax_invalidate_mapping_entry_sync(mapping, index);
- clear_shadow_entry(mapping, index, entry);
- return 1;
-}
-
/**
* folio_invalidate - Invalidate part or all of a folio.
* @folio: The folio which is affected.
@@ -494,6 +476,7 @@ unsigned long mapping_try_invalidate(str
unsigned long ret;
unsigned long count = 0;
int i;
+ bool xa_has_values = false;
folio_batch_init(&fbatch);
while (find_lock_entries(mapping, &index, end, &fbatch, indices)) {
@@ -503,8 +486,8 @@ unsigned long mapping_try_invalidate(str
/* We rely upon deletion not changing folio->index */
if (xa_is_value(folio)) {
- count += invalidate_exceptional_entry(mapping,
- indices[i], folio);
+ xa_has_values = true;
+ count++;
continue;
}
@@ -522,6 +505,10 @@ unsigned long mapping_try_invalidate(str
}
count += ret;
}
+
+ if (xa_has_values)
+ clear_shadow_entry(mapping, &fbatch, indices);
+
folio_batch_remove_exceptionals(&fbatch);
folio_batch_release(&fbatch);
cond_resched();
@@ -616,6 +603,7 @@ int invalidate_inode_pages2_range(struct
int ret = 0;
int ret2 = 0;
int did_range_unmap = 0;
+ bool xa_has_values = false;
if (mapping_empty(mapping))
return 0;
@@ -629,8 +617,9 @@ int invalidate_inode_pages2_range(struct
/* We rely upon deletion not changing folio->index */
if (xa_is_value(folio)) {
- if (!invalidate_exceptional_entry2(mapping,
- indices[i], folio))
+ xa_has_values = true;
+ if (dax_mapping(mapping) &&
+ !dax_invalidate_mapping_entry_sync(mapping, indices[i]))
ret = -EBUSY;
continue;
}
@@ -666,6 +655,10 @@ int invalidate_inode_pages2_range(struct
ret = ret2;
folio_unlock(folio);
}
+
+ if (xa_has_values)
+ clear_shadow_entry(mapping, &fbatch, indices);
+
folio_batch_remove_exceptionals(&fbatch);
folio_batch_release(&fbatch);
cond_resched();
_
Patches currently in -mm which might be from yuzhao@xxxxxxxxxx are
mm-truncate-batch-clear-shadow-entries.patch
