The patch titled
readahead: thrashing recovery method
has been removed from the -mm tree. Its filename was
readahead-thrashing-recovery-method.patch
This patch was dropped because an updated version will be merged
------------------------------------------------------
Subject: readahead: thrashing recovery method
From: Wu Fengguang <wfg@xxxxxxxxxxxxxxxx>
Readahead policy after thrashing.
It tries to recover gracefully from the thrashing.
Signed-off-by: Wu Fengguang <wfg@xxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/readahead.c | 42 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 42 insertions(+)
diff -puN mm/readahead.c~readahead-thrashing-recovery-method mm/readahead.c
--- a/mm/readahead.c~readahead-thrashing-recovery-method
+++ a/mm/readahead.c
@@ -1540,6 +1540,48 @@ try_backward_prefetching(struct file_ra_
return 1;
}
+/*
+ * Readahead thrashing recovery.
+ */
+static unsigned long
+thrashing_recovery_readahead(struct address_space *mapping,
+ struct file *filp, struct file_ra_state *ra,
+ pgoff_t offset, unsigned long ra_max)
+{
+ unsigned long ra_size;
+
+#ifdef CONFIG_DEBUG_READAHEAD
+ if (probe_page(mapping, offset - 1))
+ ra_account(ra, RA_EVENT_READAHEAD_MUTILATE,
+ ra->readahead_index - offset);
+ ra_account(ra, RA_EVENT_READAHEAD_THRASHING,
+ ra->readahead_index - offset);
+#endif
+
+ if (offset < ra->ra_index) {
+ /*
+ * Thrashed when we are in [la_index, ra_index), i.e.
+ * the old chunk is lost soon after the new one is allocated.
+ * Ensure that we recover all needed pages in the old chunk.
+ * And futher keep the lookahead_index untouched.
+ */
+ ra_size = ra->lookahead_index - offset;
+ } else {
+ /* After thrashing, we know the exact thrashing-threshold. */
+ ra_size = offset - ra->la_index;
+ update_ra_thrash_bytes(mapping->backing_dev_info, ra_size);
+
+ /* And be cooperative: the system may be hunting for memory. */
+ ra_size = MIN_RA_PAGES + ra_size / 2;
+ }
+
+ ra_set_class(ra, RA_CLASS_THRASHING);
+ ra_set_index(ra, offset, offset);
+ ra_set_size(ra, ra_size, 0);
+
+ return ra_submit(ra, mapping, filp);
+}
+
#endif /* CONFIG_ADAPTIVE_READAHEAD */
/*
_
Patches currently in -mm which might be from wfg@xxxxxxxxxxxxxxxx are
origin.patch
readahead-thrashing-recovery-method.patch
readahead-thrashing-recovery-method-check-unbalanced-aging.patch
readahead-thrashing-recovery-method-refill-holes.patch
readahead-call-scheme.patch
readahead-call-scheme-cleanup.patch
readahead-call-scheme-catch-thrashing-on-lookahead-time.patch
readahead-call-scheme-doc-fixes-for-readahead.patch
readahead-laptop-mode.patch
readahead-loop-case.patch
readahead-nfsd-case.patch
readahead-remove-parameter-ra_max-from-thrashing_recovery_readahead.patch
readahead-remove-parameter-ra_max-from-adjust_rala.patch
readahead-state-based-method-protect-against-tiny-size.patch
readahead-rename-state_based_readahead-to-clock_based_readahead.patch
readahead-account-i-o-block-times-for-stock-readahead.patch
readahead-rescue_pages-updates.patch
readahead-remove-noaction-shrink-events.patch
readahead-remove-size-limit-on-read_ahead_kb.patch
readahead-remove-size-limit-of-max_sectors_kb-on-read_ahead_kb.patch
readahead-partial-sendfile-fix.patch
readahead-turn-on-by-default.patch
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