The patch titled
readahead: initial method - guiding sizes
has been added to the -mm tree. Its filename is
readahead-initial-method-guiding-sizes.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: initial method - guiding sizes
From: Wu Fengguang <wfg@xxxxxxxxxxxxxxxx>
Introduce three guiding sizes for the initial readahead method.
- ra_pages0: min readahead on start-of-file
- ra_thrash_bytes: estimated thrashing threshold
ra_thrash_bytes defaults to large value:
- most systems don't have the danger of thrashing
- it increases slowly and drops rapidly
Signed-off-by: Wu Fengguang <wfg@xxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
block/ll_rw_blk.c | 4 +---
include/linux/backing-dev.h | 2 ++
mm/readahead.c | 5 +++++
3 files changed, 8 insertions(+), 3 deletions(-)
diff -puN block/ll_rw_blk.c~readahead-initial-method-guiding-sizes block/ll_rw_blk.c
--- a/block/ll_rw_blk.c~readahead-initial-method-guiding-sizes
+++ a/block/ll_rw_blk.c
@@ -214,9 +214,6 @@ void blk_queue_make_request(request_queu
blk_queue_max_phys_segments(q, MAX_PHYS_SEGMENTS);
blk_queue_max_hw_segments(q, MAX_HW_SEGMENTS);
q->make_request_fn = mfn;
- q->backing_dev_info.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
- q->backing_dev_info.state = 0;
- q->backing_dev_info.capabilities = BDI_CAP_MAP_COPY;
blk_queue_max_sectors(q, SAFE_MAX_SECTORS);
blk_queue_hardsect_size(q, 512);
blk_queue_dma_alignment(q, 511);
@@ -1848,6 +1845,7 @@ request_queue_t *blk_alloc_queue_node(gf
q->kobj.ktype = &queue_ktype;
kobject_init(&q->kobj);
+ q->backing_dev_info = default_backing_dev_info;
q->backing_dev_info.unplug_io_fn = blk_backing_dev_unplug;
q->backing_dev_info.unplug_io_data = q;
diff -puN include/linux/backing-dev.h~readahead-initial-method-guiding-sizes include/linux/backing-dev.h
--- a/include/linux/backing-dev.h~readahead-initial-method-guiding-sizes
+++ a/include/linux/backing-dev.h
@@ -26,6 +26,8 @@ typedef int (congested_fn)(void *, int);
struct backing_dev_info {
unsigned long ra_pages; /* max readahead in PAGE_CACHE_SIZE units */
+ unsigned long ra_pages0; /* min readahead on start of file */
+ unsigned long ra_thrash_bytes; /* estimated thrashing threshold */
unsigned long state; /* Always use atomic bitops on this */
unsigned int capabilities; /* Device capabilities */
congested_fn *congested_fn; /* Function pointer if device is md/dm */
diff -puN mm/readahead.c~readahead-initial-method-guiding-sizes mm/readahead.c
--- a/mm/readahead.c~readahead-initial-method-guiding-sizes
+++ a/mm/readahead.c
@@ -31,6 +31,9 @@
* Adaptive read-ahead parameters.
*/
+/* Default initial read-ahead size. */
+#define INITIAL_RA_PAGES DIV_ROUND_UP(64*1024, PAGE_CACHE_SIZE)
+
/* In laptop mode, poll delayed look-ahead on every ## pages read. */
#define LAPTOP_POLL_INTERVAL 16
@@ -113,6 +116,8 @@ EXPORT_SYMBOL(default_unplug_io_fn);
struct backing_dev_info default_backing_dev_info = {
.ra_pages = MAX_RA_PAGES,
+ .ra_pages0 = INITIAL_RA_PAGES,
+ .ra_thrash_bytes = MAX_RA_PAGES * PAGE_CACHE_SIZE,
.state = 0,
.capabilities = BDI_CAP_MAP_COPY,
.unplug_io_fn = default_unplug_io_fn,
_
Patches currently in -mm which might be from wfg@xxxxxxxxxxxxxxxx are
readahead-kconfig-options.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-rescue_pages.patch
readahead-sysctl-parameters.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-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-laptop-mode.patch
readahead-loop-case.patch
readahead-nfsd-case.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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