84 lines
2.9 KiB
Diff
84 lines
2.9 KiB
Diff
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From 1a8f5adc2028bd7a11a96f85abae6a0e051c7ba4 Mon Sep 17 00:00:00 2001
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From: Kent Overstreet <kent.overstreet@linux.dev>
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Date: Sun, 17 Nov 2024 14:39:46 -0500
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Subject: [PATCH 099/213] bcachefs: btree_and_journal_iter: don't iterate over
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too many whiteouts when prefetching
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Content-Type: text/plain; charset="utf-8"
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Content-Transfer-Encoding: 8bit
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To help ameloriate issues with peek operations having to skip over
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deletions in the journal - just bail out if all we're doing is
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prefetching btree nodes.
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Since btree node prefetching runs every time we iterate to a new node,
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and has to sequentially scan ahead, this avoids another O(n^2).
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Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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Signed-off-by: Alexander Miroshnichenko <alex@millerson.name>
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---
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fs/bcachefs/btree_iter.c | 2 ++
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fs/bcachefs/btree_journal_iter.c | 7 +++++++
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fs/bcachefs/btree_journal_iter.h | 1 +
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3 files changed, 10 insertions(+)
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diff --git a/fs/bcachefs/btree_iter.c b/fs/bcachefs/btree_iter.c
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index ed74f0655d98..89f9665ce70d 100644
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--- a/fs/bcachefs/btree_iter.c
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+++ b/fs/bcachefs/btree_iter.c
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@@ -825,6 +825,8 @@ static int btree_path_prefetch_j(struct btree_trans *trans, struct btree_path *p
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bch2_bkey_buf_init(&tmp);
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+ jiter->fail_if_too_many_whiteouts = true;
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+
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while (nr-- && !ret) {
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if (!bch2_btree_node_relock(trans, path, path->level))
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break;
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diff --git a/fs/bcachefs/btree_journal_iter.c b/fs/bcachefs/btree_journal_iter.c
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index dbc9bc233cca..cc7f5fad90c6 100644
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--- a/fs/bcachefs/btree_journal_iter.c
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+++ b/fs/bcachefs/btree_journal_iter.c
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@@ -426,6 +426,7 @@ static void btree_and_journal_iter_prefetch(struct btree_and_journal_iter *_iter
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: (level > 1 ? 1 : 16);
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iter.prefetch = false;
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+ iter.fail_if_too_many_whiteouts = true;
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bch2_bkey_buf_init(&tmp);
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while (nr--) {
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@@ -444,6 +445,7 @@ static void btree_and_journal_iter_prefetch(struct btree_and_journal_iter *_iter
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struct bkey_s_c bch2_btree_and_journal_iter_peek(struct btree_and_journal_iter *iter)
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{
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struct bkey_s_c btree_k, journal_k = bkey_s_c_null, ret;
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+ size_t iters = 0;
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if (iter->prefetch && iter->journal.level)
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btree_and_journal_iter_prefetch(iter);
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@@ -451,6 +453,11 @@ struct bkey_s_c bch2_btree_and_journal_iter_peek(struct btree_and_journal_iter *
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if (iter->at_end)
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return bkey_s_c_null;
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+ iters++;
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+
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+ if (iters > 20 && iter->fail_if_too_many_whiteouts)
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+ return bkey_s_c_null;
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+
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while ((btree_k = bch2_journal_iter_peek_btree(iter)).k &&
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bpos_lt(btree_k.k->p, iter->pos))
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bch2_journal_iter_advance_btree(iter);
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diff --git a/fs/bcachefs/btree_journal_iter.h b/fs/bcachefs/btree_journal_iter.h
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index 118ada4cdd1b..9e8f8ab1c6ff 100644
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--- a/fs/bcachefs/btree_journal_iter.h
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+++ b/fs/bcachefs/btree_journal_iter.h
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@@ -26,6 +26,7 @@ struct btree_and_journal_iter {
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struct bpos pos;
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bool at_end;
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bool prefetch;
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+ bool fail_if_too_many_whiteouts;
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};
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static inline int __journal_key_btree_cmp(enum btree_id l_btree_id,
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--
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2.45.2
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