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linux/include/trace/events/vmscan.h
Josef Bacik 9092c71bb7 mm: use sc->priority for slab shrink targets 
Previously we were using the ratio of the number of lru pages scanned to
the number of eligible lru pages to determine the number of slab objects
to scan.  The problem with this is that these two things have nothing to
do with each other, so in slab heavy work loads where there is little to
no page cache we can end up with the pages scanned being a very low
number.  This means that we reclaim next to no slab pages and waste a
lot of time reclaiming small amounts of space.

Consider the following scenario, where we have the following values and
the rest of the memory usage is in slab

  Active:            58840 kB
  Inactive:          46860 kB

Every time we do a get_scan_count() we do this

  scan = size >> sc->priority

where sc->priority starts at DEF_PRIORITY, which is 12.  The first loop
through reclaim would result in a scan target of 2 pages to 11715 total
inactive pages, and 3 pages to 14710 total active pages.  This is a
really really small target for a system that is entirely slab pages.
And this is super optimistic, this assumes we even get to scan these
pages.  We don't increment sc->nr_scanned unless we 1) isolate the page,
which assumes it's not in use, and 2) can lock the page.  Under pressure
these numbers could probably go down, I'm sure there's some random pages
from daemons that aren't actually in use, so the targets get even
smaller.

Instead use sc->priority in the same way we use it to determine scan
amounts for the lru's.  This generally equates to pages.  Consider the
following

  slab_pages = (nr_objects * object_size) / PAGE_SIZE

What we would like to do is

  scan = slab_pages >> sc->priority

but we don't know the number of slab pages each shrinker controls, only
the objects.  However say that theoretically we knew how many pages a
shrinker controlled, we'd still have to convert this to objects, which
would look like the following

  scan = shrinker_pages >> sc->priority
  scan_objects = (PAGE_SIZE / object_size) * scan

or written another way

  scan_objects = (shrinker_pages >> sc->priority) *
		 (PAGE_SIZE / object_size)

which can thus be written

  scan_objects = ((shrinker_pages * PAGE_SIZE) / object_size) >>
		 sc->priority

which is just

  scan_objects = nr_objects >> sc->priority

We don't need to know exactly how many pages each shrinker represents,
it's objects are all the information we need.  Making this change allows
us to place an appropriate amount of pressure on the shrinker pools for
their relative size.

Link: http://lkml.kernel.org/r/1510780549-6812-1-git-send-email-josef@toxicpanda.com
Signed-off-by: Josef Bacik <jbacik@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Dave Chinner <david@fromorbit.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31 17:18:36 -08:00

475 lines
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/* SPDX-License-Identifier: GPL-2.0 */
#undef TRACE_SYSTEM
#define TRACE_SYSTEM vmscan
#if !defined(_TRACE_VMSCAN_H) || defined(TRACE_HEADER_MULTI_READ)
#define _TRACE_VMSCAN_H
#include <linux/types.h>
#include <linux/tracepoint.h>
#include <linux/mm.h>
#include <linux/memcontrol.h>
#include <trace/events/mmflags.h>
#define RECLAIM_WB_ANON 0x0001u
#define RECLAIM_WB_FILE 0x0002u
#define RECLAIM_WB_MIXED 0x0010u
#define RECLAIM_WB_SYNC 0x0004u /* Unused, all reclaim async */
#define RECLAIM_WB_ASYNC 0x0008u
#define RECLAIM_WB_LRU (RECLAIM_WB_ANON|RECLAIM_WB_FILE)
#define show_reclaim_flags(flags) \
(flags) ? __print_flags(flags, "|", \
{RECLAIM_WB_ANON, "RECLAIM_WB_ANON"}, \
{RECLAIM_WB_FILE, "RECLAIM_WB_FILE"}, \
{RECLAIM_WB_MIXED, "RECLAIM_WB_MIXED"}, \
{RECLAIM_WB_SYNC, "RECLAIM_WB_SYNC"}, \
{RECLAIM_WB_ASYNC, "RECLAIM_WB_ASYNC"} \
) : "RECLAIM_WB_NONE"
#define trace_reclaim_flags(page) ( \
(page_is_file_cache(page) ? RECLAIM_WB_FILE : RECLAIM_WB_ANON) | \
(RECLAIM_WB_ASYNC) \
)
#define trace_shrink_flags(file) \
( \
(file ? RECLAIM_WB_FILE : RECLAIM_WB_ANON) | \
(RECLAIM_WB_ASYNC) \
)
TRACE_EVENT(mm_vmscan_kswapd_sleep,
TP_PROTO(int nid),
TP_ARGS(nid),
TP_STRUCT__entry(
__field( int, nid )
),
TP_fast_assign(
__entry->nid = nid;
),
TP_printk("nid=%d", __entry->nid)
);
TRACE_EVENT(mm_vmscan_kswapd_wake,
TP_PROTO(int nid, int zid, int order),
TP_ARGS(nid, zid, order),
TP_STRUCT__entry(
__field( int, nid )
__field( int, zid )
__field( int, order )
),
TP_fast_assign(
__entry->nid = nid;
__entry->zid = zid;
__entry->order = order;
),
TP_printk("nid=%d zid=%d order=%d", __entry->nid, __entry->zid, __entry->order)
);
TRACE_EVENT(mm_vmscan_wakeup_kswapd,
TP_PROTO(int nid, int zid, int order),
TP_ARGS(nid, zid, order),
TP_STRUCT__entry(
__field( int, nid )
__field( int, zid )
__field( int, order )
),
TP_fast_assign(
__entry->nid = nid;
__entry->zid = zid;
__entry->order = order;
),
TP_printk("nid=%d zid=%d order=%d",
__entry->nid,
__entry->zid,
__entry->order)
);
DECLARE_EVENT_CLASS(mm_vmscan_direct_reclaim_begin_template,
TP_PROTO(int order, int may_writepage, gfp_t gfp_flags, int classzone_idx),
TP_ARGS(order, may_writepage, gfp_flags, classzone_idx),
TP_STRUCT__entry(
__field( int, order )
__field( int, may_writepage )
__field( gfp_t, gfp_flags )
__field( int, classzone_idx )
),
TP_fast_assign(
__entry->order = order;
__entry->may_writepage = may_writepage;
__entry->gfp_flags = gfp_flags;
__entry->classzone_idx = classzone_idx;
),
TP_printk("order=%d may_writepage=%d gfp_flags=%s classzone_idx=%d",
__entry->order,
__entry->may_writepage,
show_gfp_flags(__entry->gfp_flags),
__entry->classzone_idx)
);
DEFINE_EVENT(mm_vmscan_direct_reclaim_begin_template, mm_vmscan_direct_reclaim_begin,
TP_PROTO(int order, int may_writepage, gfp_t gfp_flags, int classzone_idx),
TP_ARGS(order, may_writepage, gfp_flags, classzone_idx)
);
#ifdef CONFIG_MEMCG
DEFINE_EVENT(mm_vmscan_direct_reclaim_begin_template, mm_vmscan_memcg_reclaim_begin,
TP_PROTO(int order, int may_writepage, gfp_t gfp_flags, int classzone_idx),
TP_ARGS(order, may_writepage, gfp_flags, classzone_idx)
);
DEFINE_EVENT(mm_vmscan_direct_reclaim_begin_template, mm_vmscan_memcg_softlimit_reclaim_begin,
TP_PROTO(int order, int may_writepage, gfp_t gfp_flags, int classzone_idx),
TP_ARGS(order, may_writepage, gfp_flags, classzone_idx)
);
#endif /* CONFIG_MEMCG */
DECLARE_EVENT_CLASS(mm_vmscan_direct_reclaim_end_template,
TP_PROTO(unsigned long nr_reclaimed),
TP_ARGS(nr_reclaimed),
TP_STRUCT__entry(
__field( unsigned long, nr_reclaimed )
),
TP_fast_assign(
__entry->nr_reclaimed = nr_reclaimed;
),
TP_printk("nr_reclaimed=%lu", __entry->nr_reclaimed)
);
DEFINE_EVENT(mm_vmscan_direct_reclaim_end_template, mm_vmscan_direct_reclaim_end,
TP_PROTO(unsigned long nr_reclaimed),
TP_ARGS(nr_reclaimed)
);
#ifdef CONFIG_MEMCG
DEFINE_EVENT(mm_vmscan_direct_reclaim_end_template, mm_vmscan_memcg_reclaim_end,
TP_PROTO(unsigned long nr_reclaimed),
TP_ARGS(nr_reclaimed)
);
DEFINE_EVENT(mm_vmscan_direct_reclaim_end_template, mm_vmscan_memcg_softlimit_reclaim_end,
TP_PROTO(unsigned long nr_reclaimed),
TP_ARGS(nr_reclaimed)
);
#endif /* CONFIG_MEMCG */
TRACE_EVENT(mm_shrink_slab_start,
TP_PROTO(struct shrinker *shr, struct shrink_control *sc,
long nr_objects_to_shrink, unsigned long cache_items,
unsigned long long delta, unsigned long total_scan,
int priority),
TP_ARGS(shr, sc, nr_objects_to_shrink, cache_items, delta, total_scan,
priority),
TP_STRUCT__entry(
__field(struct shrinker *, shr)
__field(void *, shrink)
__field(int, nid)
__field(long, nr_objects_to_shrink)
__field(gfp_t, gfp_flags)
__field(unsigned long, cache_items)
__field(unsigned long long, delta)
__field(unsigned long, total_scan)
__field(int, priority)
),
TP_fast_assign(
__entry->shr = shr;
__entry->shrink = shr->scan_objects;
__entry->nid = sc->nid;
__entry->nr_objects_to_shrink = nr_objects_to_shrink;
__entry->gfp_flags = sc->gfp_mask;
__entry->cache_items = cache_items;
__entry->delta = delta;
__entry->total_scan = total_scan;
__entry->priority = priority;
),
TP_printk("%pF %p: nid: %d objects to shrink %ld gfp_flags %s cache items %ld delta %lld total_scan %ld priority %d",
__entry->shrink,
__entry->shr,
__entry->nid,
__entry->nr_objects_to_shrink,
show_gfp_flags(__entry->gfp_flags),
__entry->cache_items,
__entry->delta,
__entry->total_scan,
__entry->priority)
);
TRACE_EVENT(mm_shrink_slab_end,
TP_PROTO(struct shrinker *shr, int nid, int shrinker_retval,
long unused_scan_cnt, long new_scan_cnt, long total_scan),
TP_ARGS(shr, nid, shrinker_retval, unused_scan_cnt, new_scan_cnt,
total_scan),
TP_STRUCT__entry(
__field(struct shrinker *, shr)
__field(int, nid)
__field(void *, shrink)
__field(long, unused_scan)
__field(long, new_scan)
__field(int, retval)
__field(long, total_scan)
),
TP_fast_assign(
__entry->shr = shr;
__entry->nid = nid;
__entry->shrink = shr->scan_objects;
__entry->unused_scan = unused_scan_cnt;
__entry->new_scan = new_scan_cnt;
__entry->retval = shrinker_retval;
__entry->total_scan = total_scan;
),
TP_printk("%pF %p: nid: %d unused scan count %ld new scan count %ld total_scan %ld last shrinker return val %d",
__entry->shrink,
__entry->shr,
__entry->nid,
__entry->unused_scan,
__entry->new_scan,
__entry->total_scan,
__entry->retval)
);
TRACE_EVENT(mm_vmscan_lru_isolate,
TP_PROTO(int classzone_idx,
int order,
unsigned long nr_requested,
unsigned long nr_scanned,
unsigned long nr_skipped,
unsigned long nr_taken,
isolate_mode_t isolate_mode,
int lru),
TP_ARGS(classzone_idx, order, nr_requested, nr_scanned, nr_skipped, nr_taken, isolate_mode, lru),
TP_STRUCT__entry(
__field(int, classzone_idx)
__field(int, order)
__field(unsigned long, nr_requested)
__field(unsigned long, nr_scanned)
__field(unsigned long, nr_skipped)
__field(unsigned long, nr_taken)
__field(isolate_mode_t, isolate_mode)
__field(int, lru)
),
TP_fast_assign(
__entry->classzone_idx = classzone_idx;
__entry->order = order;
__entry->nr_requested = nr_requested;
__entry->nr_scanned = nr_scanned;
__entry->nr_skipped = nr_skipped;
__entry->nr_taken = nr_taken;
__entry->isolate_mode = isolate_mode;
__entry->lru = lru;
),
TP_printk("isolate_mode=%d classzone=%d order=%d nr_requested=%lu nr_scanned=%lu nr_skipped=%lu nr_taken=%lu lru=%s",
__entry->isolate_mode,
__entry->classzone_idx,
__entry->order,
__entry->nr_requested,
__entry->nr_scanned,
__entry->nr_skipped,
__entry->nr_taken,
__print_symbolic(__entry->lru, LRU_NAMES))
);
TRACE_EVENT(mm_vmscan_writepage,
TP_PROTO(struct page *page),
TP_ARGS(page),
TP_STRUCT__entry(
__field(unsigned long, pfn)
__field(int, reclaim_flags)
),
TP_fast_assign(
__entry->pfn = page_to_pfn(page);
__entry->reclaim_flags = trace_reclaim_flags(page);
),
TP_printk("page=%p pfn=%lu flags=%s",
pfn_to_page(__entry->pfn),
__entry->pfn,
show_reclaim_flags(__entry->reclaim_flags))
);
TRACE_EVENT(mm_vmscan_lru_shrink_inactive,
TP_PROTO(int nid,
unsigned long nr_scanned, unsigned long nr_reclaimed,
unsigned long nr_dirty, unsigned long nr_writeback,
unsigned long nr_congested, unsigned long nr_immediate,
unsigned long nr_activate, unsigned long nr_ref_keep,
unsigned long nr_unmap_fail,
int priority, int file),
TP_ARGS(nid, nr_scanned, nr_reclaimed, nr_dirty, nr_writeback,
nr_congested, nr_immediate, nr_activate, nr_ref_keep,
nr_unmap_fail, priority, file),
TP_STRUCT__entry(
__field(int, nid)
__field(unsigned long, nr_scanned)
__field(unsigned long, nr_reclaimed)
__field(unsigned long, nr_dirty)
__field(unsigned long, nr_writeback)
__field(unsigned long, nr_congested)
__field(unsigned long, nr_immediate)
__field(unsigned long, nr_activate)
__field(unsigned long, nr_ref_keep)
__field(unsigned long, nr_unmap_fail)
__field(int, priority)
__field(int, reclaim_flags)
),
TP_fast_assign(
__entry->nid = nid;
__entry->nr_scanned = nr_scanned;
__entry->nr_reclaimed = nr_reclaimed;
__entry->nr_dirty = nr_dirty;
__entry->nr_writeback = nr_writeback;
__entry->nr_congested = nr_congested;
__entry->nr_immediate = nr_immediate;
__entry->nr_activate = nr_activate;
__entry->nr_ref_keep = nr_ref_keep;
__entry->nr_unmap_fail = nr_unmap_fail;
__entry->priority = priority;
__entry->reclaim_flags = trace_shrink_flags(file);
),
TP_printk("nid=%d nr_scanned=%ld nr_reclaimed=%ld nr_dirty=%ld nr_writeback=%ld nr_congested=%ld nr_immediate=%ld nr_activate=%ld nr_ref_keep=%ld nr_unmap_fail=%ld priority=%d flags=%s",
__entry->nid,
__entry->nr_scanned, __entry->nr_reclaimed,
__entry->nr_dirty, __entry->nr_writeback,
__entry->nr_congested, __entry->nr_immediate,
__entry->nr_activate, __entry->nr_ref_keep,
__entry->nr_unmap_fail, __entry->priority,
show_reclaim_flags(__entry->reclaim_flags))
);
TRACE_EVENT(mm_vmscan_lru_shrink_active,
TP_PROTO(int nid, unsigned long nr_taken,
unsigned long nr_active, unsigned long nr_deactivated,
unsigned long nr_referenced, int priority, int file),
TP_ARGS(nid, nr_taken, nr_active, nr_deactivated, nr_referenced, priority, file),
TP_STRUCT__entry(
__field(int, nid)
__field(unsigned long, nr_taken)
__field(unsigned long, nr_active)
__field(unsigned long, nr_deactivated)
__field(unsigned long, nr_referenced)
__field(int, priority)
__field(int, reclaim_flags)
),
TP_fast_assign(
__entry->nid = nid;
__entry->nr_taken = nr_taken;
__entry->nr_active = nr_active;
__entry->nr_deactivated = nr_deactivated;
__entry->nr_referenced = nr_referenced;
__entry->priority = priority;
__entry->reclaim_flags = trace_shrink_flags(file);
),
TP_printk("nid=%d nr_taken=%ld nr_active=%ld nr_deactivated=%ld nr_referenced=%ld priority=%d flags=%s",
__entry->nid,
__entry->nr_taken,
__entry->nr_active, __entry->nr_deactivated, __entry->nr_referenced,
__entry->priority,
show_reclaim_flags(__entry->reclaim_flags))
);
TRACE_EVENT(mm_vmscan_inactive_list_is_low,
TP_PROTO(int nid, int reclaim_idx,
unsigned long total_inactive, unsigned long inactive,
unsigned long total_active, unsigned long active,
unsigned long ratio, int file),
TP_ARGS(nid, reclaim_idx, total_inactive, inactive, total_active, active, ratio, file),
TP_STRUCT__entry(
__field(int, nid)
__field(int, reclaim_idx)
__field(unsigned long, total_inactive)
__field(unsigned long, inactive)
__field(unsigned long, total_active)
__field(unsigned long, active)
__field(unsigned long, ratio)
__field(int, reclaim_flags)
),
TP_fast_assign(
__entry->nid = nid;
__entry->reclaim_idx = reclaim_idx;
__entry->total_inactive = total_inactive;
__entry->inactive = inactive;
__entry->total_active = total_active;
__entry->active = active;
__entry->ratio = ratio;
__entry->reclaim_flags = trace_shrink_flags(file) & RECLAIM_WB_LRU;
),
TP_printk("nid=%d reclaim_idx=%d total_inactive=%ld inactive=%ld total_active=%ld active=%ld ratio=%ld flags=%s",
__entry->nid,
__entry->reclaim_idx,
__entry->total_inactive, __entry->inactive,
__entry->total_active, __entry->active,
__entry->ratio,
show_reclaim_flags(__entry->reclaim_flags))
);
#endif /* _TRACE_VMSCAN_H */
/* This part must be outside protection */
#include <trace/define_trace.h>
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