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mm: vmscan: remove reclaim_mode_t 

There is little motiviation for reclaim_mode_t once RECLAIM_MODE_[A]SYNC
and lumpy reclaim have been removed.  This patch gets rid of
reclaim_mode_t as well and improves the documentation about what
reclaim/compaction is and when it is triggered.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ying Han <yinghan@google.com>
Cc: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Mel Gorman 2012-05-29 15:06:20 -07:00 committed by Linus Torvalds
parent 41ac1999c3
commit 23b9da55c5
2 changed files with 24 additions and 52 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
include/trace/events/vmscan.h
View File

@ -25,12 +25,12 @@
{RECLAIM_WB_ASYNC, "RECLAIM_WB_ASYNC"} \
) : "RECLAIM_WB_NONE"
#define trace_reclaim_flags(page, sync) ( \
#define trace_reclaim_flags(page) ( \
(page_is_file_cache(page) ? RECLAIM_WB_FILE : RECLAIM_WB_ANON) | \
(RECLAIM_WB_ASYNC) \
)
#define trace_shrink_flags(file, sync) \
#define trace_shrink_flags(file) \
( \
(file ? RECLAIM_WB_FILE : RECLAIM_WB_ANON) | \
(RECLAIM_WB_ASYNC) \

72
mm/vmscan.c
View File

@ -53,16 +53,6 @@
#define CREATE_TRACE_POINTS
#include <trace/events/vmscan.h>
/*
* reclaim_mode determines how the inactive list is shrunk
* RECLAIM_MODE_SINGLE: Reclaim only order-0 pages
* RECLAIM_MODE_COMPACTION: For high-order allocations, reclaim a number of
* order-0 pages and then compact the zone
*/
typedef unsigned __bitwise__ reclaim_mode_t;
#define RECLAIM_MODE_SINGLE ((__force reclaim_mode_t)0x01u)
#define RECLAIM_MODE_COMPACTION ((__force reclaim_mode_t)0x10u)
struct scan_control {
/* Incremented by the number of inactive pages that were scanned */
unsigned long nr_scanned;
@ -88,12 +78,6 @@ struct scan_control {
int order;
/*
* Intend to reclaim enough continuous memory rather than reclaim
* enough amount of memory. i.e, mode for high order allocation.
*/
reclaim_mode_t reclaim_mode;
/*
* The memory cgroup that hit its limit and as a result is the
* primary target of this reclaim invocation.
@ -356,25 +340,6 @@ out:
return ret;
}
static void set_reclaim_mode(int priority, struct scan_control *sc)
{
/*
* Restrict reclaim/compaction to costly allocations or when
* under memory pressure
*/
if (COMPACTION_BUILD && sc->order &&
(sc->order > PAGE_ALLOC_COSTLY_ORDER ||
priority < DEF_PRIORITY - 2))
sc->reclaim_mode = RECLAIM_MODE_COMPACTION;
else
sc->reclaim_mode = RECLAIM_MODE_SINGLE;
}
static void reset_reclaim_mode(struct scan_control *sc)
{
sc->reclaim_mode = RECLAIM_MODE_SINGLE;
}
static inline int is_page_cache_freeable(struct page *page)
{
/*
@ -497,8 +462,7 @@ static pageout_t pageout(struct page *page, struct address_space *mapping,
/* synchronous write or broken a_ops? */
ClearPageReclaim(page);
}
trace_mm_vmscan_writepage(page,
trace_reclaim_flags(page, sc->reclaim_mode));
trace_mm_vmscan_writepage(page, trace_reclaim_flags(page));
inc_zone_page_state(page, NR_VMSCAN_WRITE);
return PAGE_SUCCESS;
}
@ -953,7 +917,6 @@ cull_mlocked:
try_to_free_swap(page);
unlock_page(page);
putback_lru_page(page);
reset_reclaim_mode(sc);
continue;
activate_locked:
@ -1348,8 +1311,6 @@ shrink_inactive_list(unsigned long nr_to_scan, struct mem_cgroup_zone *mz,
return SWAP_CLUSTER_MAX;
}
set_reclaim_mode(priority, sc);
lru_add_drain();
if (!sc->may_unmap)
@ -1433,7 +1394,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct mem_cgroup_zone *mz,
zone_idx(zone),
nr_scanned, nr_reclaimed,
priority,
trace_shrink_flags(file, sc->reclaim_mode));
trace_shrink_flags(file));
return nr_reclaimed;
}
@ -1512,8 +1473,6 @@ static void shrink_active_list(unsigned long nr_to_scan,
lru_add_drain();
reset_reclaim_mode(sc);
if (!sc->may_unmap)
isolate_mode |= ISOLATE_UNMAPPED;
if (!sc->may_writepage)
@ -1826,23 +1785,35 @@ out:
}
}
/* Use reclaim/compaction for costly allocs or under memory pressure */
static bool in_reclaim_compaction(int priority, struct scan_control *sc)
{
if (COMPACTION_BUILD && sc->order &&
(sc->order > PAGE_ALLOC_COSTLY_ORDER ||
priority < DEF_PRIORITY - 2))
return true;
return false;
}
/*
* Reclaim/compaction depends on a number of pages being freed. To avoid
* disruption to the system, a small number of order-0 pages continue to be
* rotated and reclaimed in the normal fashion. However, by the time we get
* back to the allocator and call try_to_compact_zone(), we ensure that
* there are enough free pages for it to be likely successful
* Reclaim/compaction is used for high-order allocation requests. It reclaims
* order-0 pages before compacting the zone. should_continue_reclaim() returns
* true if more pages should be reclaimed such that when the page allocator
* calls try_to_compact_zone() that it will have enough free pages to succeed.
* It will give up earlier than that if there is difficulty reclaiming pages.
*/
static inline bool should_continue_reclaim(struct mem_cgroup_zone *mz,
unsigned long nr_reclaimed,
unsigned long nr_scanned,
int priority,
struct scan_control *sc)
{
unsigned long pages_for_compaction;
unsigned long inactive_lru_pages;
/* If not in reclaim/compaction mode, stop */
if (!(sc->reclaim_mode & RECLAIM_MODE_COMPACTION))
if (!in_reclaim_compaction(priority, sc))
return false;
/* Consider stopping depending on scan and reclaim activity */
@ -1944,7 +1915,8 @@ restart:
/* reclaim/compaction might need reclaim to continue */
if (should_continue_reclaim(mz, nr_reclaimed,
sc->nr_scanned - nr_scanned, sc))
sc->nr_scanned - nr_scanned,
priority, sc))
goto restart;
throttle_vm_writeout(sc->gfp_mask);