The patch titled
readahead nfsd case: fix uninitialized ra_min/ra_max
has been added to the -mm tree. Its filename is
readahead-nfsd-case-fix-uninitialized-ra_min-ra_max.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: readahead nfsd case: fix uninitialized ra_min/ra_max
From: Fengguang Wu <wfg@xxxxxxxxxxxxxxxx>
ra_min/ra_max are not initialized, fix it.
New benchmark numbers on
hda: ST3250820A, ATA DISK drive
hda: max request size: 512KiB
hda: 488397168 sectors (250059 MB) w/8192KiB Cache, CHS=30401/255/63, UDMA(100)
with nfs mount
mount -o tcp,rsize=$((rsize<<10)) localhost:$EXPORT $MNT
rsize stock adaptive
==================================
f
8k 3.07 2.51 -18.2%
32k 2.40 2.17 -9.6%
128k 2.40 2.35 -2.1%
ff
8k 12.44 6.40 -48.6%
32k 14.62 5.46 -62.7%
128k 15.79 5.19 -67.1%
d
8k 2.84 2.48 -12.7%
32k 2.53 1.99 -21.3%
128k 2.18 2.00 -8.3%
dd
8k 8.16 7.99 -2.1%
32k 8.27 6.88 -16.8%
128k 7.75 6.97 -10.1%
The 4 patterns tested are:
f: single file read
ff: double file parallel read
d: single dir read
dd: double dir parallel read
Signed-off-by: Fengguang Wu <wfg@xxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
mm/readahead.c | 19 +++++++++++--------
1 files changed, 11 insertions(+), 8 deletions(-)
diff -puN mm/readahead.c~readahead-nfsd-case-fix-uninitialized-ra_min-ra_max mm/readahead.c
--- a/mm/readahead.c~readahead-nfsd-case-fix-uninitialized-ra_min-ra_max
+++ a/mm/readahead.c
@@ -1617,6 +1617,10 @@ page_cache_readahead_adaptive(struct add
unsigned long ra_max;
int ret;
+ /* no read-ahead */
+ if (!ra->ra_pages)
+ return 0;
+
if (page) {
ClearPageReadahead(page);
@@ -1636,9 +1640,6 @@ page_cache_readahead_adaptive(struct add
offset + LAPTOP_POLL_INTERVAL))
return 0;
}
- } else if (ra->flags & RA_FLAG_NFSD) { /* nfsd read */
- ra_size = max_sane_readahead(req_size);
- goto readit;
}
if (page)
@@ -1648,11 +1649,13 @@ page_cache_readahead_adaptive(struct add
get_readahead_bounds(ra, &ra_min, &ra_max);
- /* read-ahead disabled? */
- if (unlikely(!ra_max || !readahead_ratio)) {
- ra_size = max_sane_readahead(req_size);
+ /* read as is */
+ if (!readahead_ratio)
+ goto readit;
+
+ /* nfsd read */
+ if (!page && (ra->flags & RA_FLAG_NFSD))
goto readit;
- }
/*
* Start of file.
@@ -1699,11 +1702,11 @@ page_cache_readahead_adaptive(struct add
return 0;
}
+readit:
/*
* Random read.
*/
ra_size = min(req_size, ra_max);
-readit:
ra_size = __do_page_cache_readahead(mapping, filp, offset, ra_size, 0);
ra_account(ra, RA_EVENT_RANDOM_READ, ra_size);
_
Patches currently in -mm which might be from wfg@xxxxxxxxxxxxxxxx are
readahead-kconfig-options.patch
readahead-kconfig-options-fix.patch
radixtree-introduce-scan-hole-data-functions.patch
mm-introduce-probe_page.patch
mm-introduce-pg_readahead.patch
readahead-add-look-ahead-support-to-__do_page_cache_readahead.patch
readahead-insert-cond_resched-calls.patch
readahead-minmax_ra_pages.patch
readahead-events-accounting.patch
readahead-events-accounting-make-readahead_debug_level-static.patch
readahead-rescue_pages.patch
readahead-sysctl-parameters.patch
readahead-sysctl-parameters-use-ctl_unnumbered.patch
readahead-sysctl-parameters-fix.patch
readahead-min-max-sizes.patch
readahead-state-based-method-aging-accounting.patch
readahead-state-based-method-routines.patch
readahead-state-based-method.patch
readahead-context-based-method.patch
readahead-context-based-method-locking-fix.patch
readahead-context-based-method-locking-fix-2.patch
readahead-initial-method-guiding-sizes.patch
readahead-initial-method-thrashing-guard-size.patch
readahead-initial-method-user-recommended-size.patch
readahead-initial-method.patch
readahead-backward-prefetching-method.patch
readahead-thrashing-recovery-method.patch
readahead-call-scheme.patch
readahead-call-scheme-ifdef-fix.patch
readahead-call-scheme-build-fix.patch
readahead-laptop-mode.patch
readahead-loop-case.patch
readahead-nfsd-case.patch
readahead-nfsd-case-fix.patch
readahead-nfsd-case-fix-uninitialized-ra_min-ra_max.patch
readahead-turn-on-by-default.patch
readahead-remove-size-limit-on-read_ahead_kb.patch
readahead-remove-size-limit-of-max_sectors_kb-on-read_ahead_kb.patch
-
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