The patch titled
Subject: z3fold: compact objects more accurately
has been added to the -mm tree. Its filename is
z3fold-compact-objects-more-accurately.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/z3fold-compact-objects-more-accurately.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/z3fold-compact-objects-more-accurately.patch
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------------------------------------------------------
From: Vitaly Wool <vitalywool@xxxxxxxxx>
Subject: z3fold: compact objects more accurately
There are several small things to be considered regarding the new
inter-page compaction mechanism. First, we better set the relevant size
in chunks to 0 in the old z3fold header for the object that has been moved
to another z3fold page. Then, we shouldn't do inter-page compaction if an
object is mapped. Lastly, free_handle should happen before
release_z3fold_page (but not in case the page is under reclaim, it will
the handle will be freed by reclaim then).
This patch addresses all three issues.
Link: http://lkml.kernel.org/r/20191127152216.6ad33745a21ba71c53606acb@xxxxxxxxx
Signed-off-by: Vitaly Wool <vitaly.vul@xxxxxxxx>
Cc: Dan Streetman <ddstreet@xxxxxxxx>
Cc: Henry Burns <henrywolfeburns@xxxxxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/z3fold.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
--- a/mm/z3fold.c~z3fold-compact-objects-more-accurately
+++ a/mm/z3fold.c
@@ -670,6 +670,7 @@ static struct z3fold_header *compact_sin
int first_idx = __idx(zhdr, FIRST);
int middle_idx = __idx(zhdr, MIDDLE);
int last_idx = __idx(zhdr, LAST);
+ unsigned short *moved_chunks = NULL;
/*
* No need to protect slots here -- all the slots are "local" and
@@ -679,14 +680,17 @@ static struct z3fold_header *compact_sin
p += ZHDR_SIZE_ALIGNED;
sz = zhdr->first_chunks << CHUNK_SHIFT;
old_handle = (unsigned long)&zhdr->slots->slot[first_idx];
+ moved_chunks = &zhdr->first_chunks;
} else if (zhdr->middle_chunks && zhdr->slots->slot[middle_idx]) {
p += zhdr->start_middle << CHUNK_SHIFT;
sz = zhdr->middle_chunks << CHUNK_SHIFT;
old_handle = (unsigned long)&zhdr->slots->slot[middle_idx];
+ moved_chunks = &zhdr->middle_chunks;
} else if (zhdr->last_chunks && zhdr->slots->slot[last_idx]) {
p += PAGE_SIZE - (zhdr->last_chunks << CHUNK_SHIFT);
sz = zhdr->last_chunks << CHUNK_SHIFT;
old_handle = (unsigned long)&zhdr->slots->slot[last_idx];
+ moved_chunks = &zhdr->last_chunks;
}
if (sz > 0) {
@@ -743,6 +747,8 @@ static struct z3fold_header *compact_sin
write_unlock(&zhdr->slots->lock);
add_to_unbuddied(pool, new_zhdr);
z3fold_page_unlock(new_zhdr);
+
+ *moved_chunks = 0;
}
return new_zhdr;
@@ -840,7 +846,7 @@ static void do_compact_page(struct z3fol
}
if (!zhdr->foreign_handles && buddy_single(zhdr) &&
- compact_single_buddy(zhdr)) {
+ zhdr->mapped_count == 0 && compact_single_buddy(zhdr)) {
if (kref_put(&zhdr->refcount, release_z3fold_page_locked))
atomic64_dec(&pool->pages_nr);
else
@@ -1254,6 +1260,8 @@ static void z3fold_free(struct z3fold_po
return;
}
+ if (!page_claimed)
+ free_handle(handle);
if (kref_put(&zhdr->refcount, release_z3fold_page_locked_list)) {
atomic64_dec(&pool->pages_nr);
return;
@@ -1263,7 +1271,6 @@ static void z3fold_free(struct z3fold_po
z3fold_page_unlock(zhdr);
return;
}
- free_handle(handle);
if (unlikely(PageIsolated(page)) ||
test_and_set_bit(NEEDS_COMPACTING, &page->private)) {
put_z3fold_header(zhdr);
_
Patches currently in -mm which might be from vitalywool@xxxxxxxxx are
z3fold-avoid-subtle-race-when-freeing-slots.patch
z3fold-compact-objects-more-accurately.patch
z3fold-protect-handle-reads.patch
