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![Jinke Han](/assets/img/avatar_default.png)
In our test of iocost, we encountered some list add/del corruptions of inner_walk list in ioc_timer_fn. The reason can be described as follows: cpu 0 cpu 1 ioc_qos_write ioc_qos_write ioc = q_to_ioc(queue); if (!ioc) { ioc = kzalloc(); ioc = q_to_ioc(queue); if (!ioc) { ioc = kzalloc(); ... rq_qos_add(q, rqos); } ... rq_qos_add(q, rqos); ... } When the io.cost.qos file is written by two cpus concurrently, rq_qos may be added to one disk twice. In that case, there will be two iocs enabled and running on one disk. They own different iocgs on their active list. In the ioc_timer_fn function, because of the iocgs from two iocs have the same root iocg, the root iocg's walk_list may be overwritten by each other and this leads to list add/del corruptions in building or destroying the inner_walk list. And so far, the blk-rq-qos framework works in case that one instance for one type rq_qos per queue by default. This patch make this explicit and also fix the crash above. Signed-off-by: Jinke Han <hanjinke.666@bytedance.com> Reviewed-by: Muchun Song <songmuchun@bytedance.com> Acked-by: Tejun Heo <tj@kernel.org> Cc: <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20220720093616.70584-1-hanjinke.666@bytedance.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
868 lines
20 KiB
C
868 lines
20 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* buffered writeback throttling. loosely based on CoDel. We can't drop
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* packets for IO scheduling, so the logic is something like this:
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*
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* - Monitor latencies in a defined window of time.
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* - If the minimum latency in the above window exceeds some target, increment
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* scaling step and scale down queue depth by a factor of 2x. The monitoring
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* window is then shrunk to 100 / sqrt(scaling step + 1).
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* - For any window where we don't have solid data on what the latencies
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* look like, retain status quo.
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* - If latencies look good, decrement scaling step.
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* - If we're only doing writes, allow the scaling step to go negative. This
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* will temporarily boost write performance, snapping back to a stable
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* scaling step of 0 if reads show up or the heavy writers finish. Unlike
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* positive scaling steps where we shrink the monitoring window, a negative
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* scaling step retains the default step==0 window size.
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*
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* Copyright (C) 2016 Jens Axboe
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*
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*/
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#include <linux/kernel.h>
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#include <linux/blk_types.h>
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#include <linux/slab.h>
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#include <linux/backing-dev.h>
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#include <linux/swap.h>
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#include "blk-wbt.h"
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#include "blk-rq-qos.h"
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#define CREATE_TRACE_POINTS
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#include <trace/events/wbt.h>
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static inline void wbt_clear_state(struct request *rq)
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{
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rq->wbt_flags = 0;
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}
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static inline enum wbt_flags wbt_flags(struct request *rq)
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{
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return rq->wbt_flags;
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}
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static inline bool wbt_is_tracked(struct request *rq)
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{
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return rq->wbt_flags & WBT_TRACKED;
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}
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static inline bool wbt_is_read(struct request *rq)
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{
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return rq->wbt_flags & WBT_READ;
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}
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enum {
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/*
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* Default setting, we'll scale up (to 75% of QD max) or down (min 1)
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* from here depending on device stats
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*/
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RWB_DEF_DEPTH = 16,
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/*
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* 100msec window
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*/
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RWB_WINDOW_NSEC = 100 * 1000 * 1000ULL,
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/*
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* Disregard stats, if we don't meet this minimum
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*/
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RWB_MIN_WRITE_SAMPLES = 3,
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/*
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* If we have this number of consecutive windows with not enough
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* information to scale up or down, scale up.
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*/
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RWB_UNKNOWN_BUMP = 5,
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};
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static inline bool rwb_enabled(struct rq_wb *rwb)
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{
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return rwb && rwb->enable_state != WBT_STATE_OFF_DEFAULT &&
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rwb->wb_normal != 0;
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}
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static void wb_timestamp(struct rq_wb *rwb, unsigned long *var)
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{
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if (rwb_enabled(rwb)) {
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const unsigned long cur = jiffies;
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if (cur != *var)
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*var = cur;
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}
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}
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/*
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* If a task was rate throttled in balance_dirty_pages() within the last
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* second or so, use that to indicate a higher cleaning rate.
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*/
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static bool wb_recent_wait(struct rq_wb *rwb)
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{
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struct bdi_writeback *wb = &rwb->rqos.q->disk->bdi->wb;
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return time_before(jiffies, wb->dirty_sleep + HZ);
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}
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static inline struct rq_wait *get_rq_wait(struct rq_wb *rwb,
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enum wbt_flags wb_acct)
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{
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if (wb_acct & WBT_KSWAPD)
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return &rwb->rq_wait[WBT_RWQ_KSWAPD];
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else if (wb_acct & WBT_DISCARD)
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return &rwb->rq_wait[WBT_RWQ_DISCARD];
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return &rwb->rq_wait[WBT_RWQ_BG];
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}
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static void rwb_wake_all(struct rq_wb *rwb)
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{
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int i;
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for (i = 0; i < WBT_NUM_RWQ; i++) {
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struct rq_wait *rqw = &rwb->rq_wait[i];
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if (wq_has_sleeper(&rqw->wait))
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wake_up_all(&rqw->wait);
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}
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}
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static void wbt_rqw_done(struct rq_wb *rwb, struct rq_wait *rqw,
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enum wbt_flags wb_acct)
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{
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int inflight, limit;
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inflight = atomic_dec_return(&rqw->inflight);
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/*
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* wbt got disabled with IO in flight. Wake up any potential
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* waiters, we don't have to do more than that.
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*/
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if (unlikely(!rwb_enabled(rwb))) {
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rwb_wake_all(rwb);
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return;
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}
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/*
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* For discards, our limit is always the background. For writes, if
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* the device does write back caching, drop further down before we
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* wake people up.
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*/
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if (wb_acct & WBT_DISCARD)
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limit = rwb->wb_background;
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else if (rwb->wc && !wb_recent_wait(rwb))
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limit = 0;
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else
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limit = rwb->wb_normal;
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/*
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* Don't wake anyone up if we are above the normal limit.
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*/
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if (inflight && inflight >= limit)
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return;
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if (wq_has_sleeper(&rqw->wait)) {
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int diff = limit - inflight;
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if (!inflight || diff >= rwb->wb_background / 2)
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wake_up_all(&rqw->wait);
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}
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}
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static void __wbt_done(struct rq_qos *rqos, enum wbt_flags wb_acct)
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{
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struct rq_wb *rwb = RQWB(rqos);
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struct rq_wait *rqw;
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if (!(wb_acct & WBT_TRACKED))
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return;
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rqw = get_rq_wait(rwb, wb_acct);
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wbt_rqw_done(rwb, rqw, wb_acct);
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}
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/*
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* Called on completion of a request. Note that it's also called when
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* a request is merged, when the request gets freed.
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*/
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static void wbt_done(struct rq_qos *rqos, struct request *rq)
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{
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struct rq_wb *rwb = RQWB(rqos);
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if (!wbt_is_tracked(rq)) {
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if (rwb->sync_cookie == rq) {
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rwb->sync_issue = 0;
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rwb->sync_cookie = NULL;
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}
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if (wbt_is_read(rq))
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wb_timestamp(rwb, &rwb->last_comp);
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} else {
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WARN_ON_ONCE(rq == rwb->sync_cookie);
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__wbt_done(rqos, wbt_flags(rq));
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}
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wbt_clear_state(rq);
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}
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static inline bool stat_sample_valid(struct blk_rq_stat *stat)
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{
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/*
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* We need at least one read sample, and a minimum of
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* RWB_MIN_WRITE_SAMPLES. We require some write samples to know
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* that it's writes impacting us, and not just some sole read on
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* a device that is in a lower power state.
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*/
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return (stat[READ].nr_samples >= 1 &&
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stat[WRITE].nr_samples >= RWB_MIN_WRITE_SAMPLES);
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}
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static u64 rwb_sync_issue_lat(struct rq_wb *rwb)
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{
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u64 now, issue = READ_ONCE(rwb->sync_issue);
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if (!issue || !rwb->sync_cookie)
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return 0;
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now = ktime_to_ns(ktime_get());
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return now - issue;
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}
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enum {
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LAT_OK = 1,
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LAT_UNKNOWN,
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LAT_UNKNOWN_WRITES,
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LAT_EXCEEDED,
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};
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static int latency_exceeded(struct rq_wb *rwb, struct blk_rq_stat *stat)
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{
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struct backing_dev_info *bdi = rwb->rqos.q->disk->bdi;
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struct rq_depth *rqd = &rwb->rq_depth;
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u64 thislat;
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/*
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* If our stored sync issue exceeds the window size, or it
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* exceeds our min target AND we haven't logged any entries,
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* flag the latency as exceeded. wbt works off completion latencies,
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* but for a flooded device, a single sync IO can take a long time
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* to complete after being issued. If this time exceeds our
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* monitoring window AND we didn't see any other completions in that
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* window, then count that sync IO as a violation of the latency.
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*/
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thislat = rwb_sync_issue_lat(rwb);
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if (thislat > rwb->cur_win_nsec ||
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(thislat > rwb->min_lat_nsec && !stat[READ].nr_samples)) {
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trace_wbt_lat(bdi, thislat);
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return LAT_EXCEEDED;
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}
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/*
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* No read/write mix, if stat isn't valid
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*/
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if (!stat_sample_valid(stat)) {
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/*
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* If we had writes in this stat window and the window is
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* current, we're only doing writes. If a task recently
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* waited or still has writes in flights, consider us doing
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* just writes as well.
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*/
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if (stat[WRITE].nr_samples || wb_recent_wait(rwb) ||
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wbt_inflight(rwb))
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return LAT_UNKNOWN_WRITES;
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return LAT_UNKNOWN;
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}
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/*
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* If the 'min' latency exceeds our target, step down.
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*/
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if (stat[READ].min > rwb->min_lat_nsec) {
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trace_wbt_lat(bdi, stat[READ].min);
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trace_wbt_stat(bdi, stat);
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return LAT_EXCEEDED;
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}
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if (rqd->scale_step)
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trace_wbt_stat(bdi, stat);
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return LAT_OK;
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}
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static void rwb_trace_step(struct rq_wb *rwb, const char *msg)
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{
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struct backing_dev_info *bdi = rwb->rqos.q->disk->bdi;
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struct rq_depth *rqd = &rwb->rq_depth;
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trace_wbt_step(bdi, msg, rqd->scale_step, rwb->cur_win_nsec,
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rwb->wb_background, rwb->wb_normal, rqd->max_depth);
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}
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static void calc_wb_limits(struct rq_wb *rwb)
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{
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if (rwb->min_lat_nsec == 0) {
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rwb->wb_normal = rwb->wb_background = 0;
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} else if (rwb->rq_depth.max_depth <= 2) {
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rwb->wb_normal = rwb->rq_depth.max_depth;
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rwb->wb_background = 1;
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} else {
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rwb->wb_normal = (rwb->rq_depth.max_depth + 1) / 2;
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rwb->wb_background = (rwb->rq_depth.max_depth + 3) / 4;
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}
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}
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static void scale_up(struct rq_wb *rwb)
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{
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if (!rq_depth_scale_up(&rwb->rq_depth))
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return;
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calc_wb_limits(rwb);
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rwb->unknown_cnt = 0;
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rwb_wake_all(rwb);
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rwb_trace_step(rwb, tracepoint_string("scale up"));
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}
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static void scale_down(struct rq_wb *rwb, bool hard_throttle)
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{
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if (!rq_depth_scale_down(&rwb->rq_depth, hard_throttle))
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return;
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calc_wb_limits(rwb);
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rwb->unknown_cnt = 0;
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rwb_trace_step(rwb, tracepoint_string("scale down"));
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}
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static void rwb_arm_timer(struct rq_wb *rwb)
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{
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struct rq_depth *rqd = &rwb->rq_depth;
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if (rqd->scale_step > 0) {
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/*
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* We should speed this up, using some variant of a fast
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* integer inverse square root calculation. Since we only do
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* this for every window expiration, it's not a huge deal,
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* though.
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*/
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rwb->cur_win_nsec = div_u64(rwb->win_nsec << 4,
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int_sqrt((rqd->scale_step + 1) << 8));
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} else {
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/*
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* For step < 0, we don't want to increase/decrease the
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* window size.
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*/
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rwb->cur_win_nsec = rwb->win_nsec;
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}
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blk_stat_activate_nsecs(rwb->cb, rwb->cur_win_nsec);
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}
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static void wb_timer_fn(struct blk_stat_callback *cb)
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{
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struct rq_wb *rwb = cb->data;
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struct rq_depth *rqd = &rwb->rq_depth;
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unsigned int inflight = wbt_inflight(rwb);
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int status;
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if (!rwb->rqos.q->disk)
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return;
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status = latency_exceeded(rwb, cb->stat);
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trace_wbt_timer(rwb->rqos.q->disk->bdi, status, rqd->scale_step,
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inflight);
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/*
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* If we exceeded the latency target, step down. If we did not,
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* step one level up. If we don't know enough to say either exceeded
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* or ok, then don't do anything.
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*/
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switch (status) {
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case LAT_EXCEEDED:
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scale_down(rwb, true);
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break;
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case LAT_OK:
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scale_up(rwb);
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break;
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case LAT_UNKNOWN_WRITES:
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/*
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* We started a the center step, but don't have a valid
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* read/write sample, but we do have writes going on.
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* Allow step to go negative, to increase write perf.
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*/
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scale_up(rwb);
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break;
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case LAT_UNKNOWN:
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if (++rwb->unknown_cnt < RWB_UNKNOWN_BUMP)
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break;
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/*
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* We get here when previously scaled reduced depth, and we
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* currently don't have a valid read/write sample. For that
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* case, slowly return to center state (step == 0).
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*/
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if (rqd->scale_step > 0)
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scale_up(rwb);
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else if (rqd->scale_step < 0)
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scale_down(rwb, false);
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break;
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default:
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break;
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}
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/*
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* Re-arm timer, if we have IO in flight
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*/
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if (rqd->scale_step || inflight)
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rwb_arm_timer(rwb);
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}
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static void wbt_update_limits(struct rq_wb *rwb)
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{
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struct rq_depth *rqd = &rwb->rq_depth;
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rqd->scale_step = 0;
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rqd->scaled_max = false;
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rq_depth_calc_max_depth(rqd);
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calc_wb_limits(rwb);
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rwb_wake_all(rwb);
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}
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u64 wbt_get_min_lat(struct request_queue *q)
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{
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struct rq_qos *rqos = wbt_rq_qos(q);
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if (!rqos)
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return 0;
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return RQWB(rqos)->min_lat_nsec;
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}
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void wbt_set_min_lat(struct request_queue *q, u64 val)
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{
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struct rq_qos *rqos = wbt_rq_qos(q);
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if (!rqos)
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return;
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RQWB(rqos)->min_lat_nsec = val;
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RQWB(rqos)->enable_state = WBT_STATE_ON_MANUAL;
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wbt_update_limits(RQWB(rqos));
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}
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static bool close_io(struct rq_wb *rwb)
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{
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const unsigned long now = jiffies;
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return time_before(now, rwb->last_issue + HZ / 10) ||
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time_before(now, rwb->last_comp + HZ / 10);
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}
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#define REQ_HIPRIO (REQ_SYNC | REQ_META | REQ_PRIO)
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static inline unsigned int get_limit(struct rq_wb *rwb, blk_opf_t opf)
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{
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unsigned int limit;
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/*
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* If we got disabled, just return UINT_MAX. This ensures that
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* we'll properly inc a new IO, and dec+wakeup at the end.
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*/
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if (!rwb_enabled(rwb))
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return UINT_MAX;
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if ((opf & REQ_OP_MASK) == REQ_OP_DISCARD)
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return rwb->wb_background;
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/*
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* At this point we know it's a buffered write. If this is
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* kswapd trying to free memory, or REQ_SYNC is set, then
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* it's WB_SYNC_ALL writeback, and we'll use the max limit for
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* that. If the write is marked as a background write, then use
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* the idle limit, or go to normal if we haven't had competing
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* IO for a bit.
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*/
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if ((opf & REQ_HIPRIO) || wb_recent_wait(rwb) || current_is_kswapd())
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limit = rwb->rq_depth.max_depth;
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else if ((opf & REQ_BACKGROUND) || close_io(rwb)) {
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/*
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* If less than 100ms since we completed unrelated IO,
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|
* limit us to half the depth for background writeback.
|
|
*/
|
|
limit = rwb->wb_background;
|
|
} else
|
|
limit = rwb->wb_normal;
|
|
|
|
return limit;
|
|
}
|
|
|
|
struct wbt_wait_data {
|
|
struct rq_wb *rwb;
|
|
enum wbt_flags wb_acct;
|
|
blk_opf_t opf;
|
|
};
|
|
|
|
static bool wbt_inflight_cb(struct rq_wait *rqw, void *private_data)
|
|
{
|
|
struct wbt_wait_data *data = private_data;
|
|
return rq_wait_inc_below(rqw, get_limit(data->rwb, data->opf));
|
|
}
|
|
|
|
static void wbt_cleanup_cb(struct rq_wait *rqw, void *private_data)
|
|
{
|
|
struct wbt_wait_data *data = private_data;
|
|
wbt_rqw_done(data->rwb, rqw, data->wb_acct);
|
|
}
|
|
|
|
/*
|
|
* Block if we will exceed our limit, or if we are currently waiting for
|
|
* the timer to kick off queuing again.
|
|
*/
|
|
static void __wbt_wait(struct rq_wb *rwb, enum wbt_flags wb_acct,
|
|
blk_opf_t opf)
|
|
{
|
|
struct rq_wait *rqw = get_rq_wait(rwb, wb_acct);
|
|
struct wbt_wait_data data = {
|
|
.rwb = rwb,
|
|
.wb_acct = wb_acct,
|
|
.opf = opf,
|
|
};
|
|
|
|
rq_qos_wait(rqw, &data, wbt_inflight_cb, wbt_cleanup_cb);
|
|
}
|
|
|
|
static inline bool wbt_should_throttle(struct bio *bio)
|
|
{
|
|
switch (bio_op(bio)) {
|
|
case REQ_OP_WRITE:
|
|
/*
|
|
* Don't throttle WRITE_ODIRECT
|
|
*/
|
|
if ((bio->bi_opf & (REQ_SYNC | REQ_IDLE)) ==
|
|
(REQ_SYNC | REQ_IDLE))
|
|
return false;
|
|
fallthrough;
|
|
case REQ_OP_DISCARD:
|
|
return true;
|
|
default:
|
|
return false;
|
|
}
|
|
}
|
|
|
|
static enum wbt_flags bio_to_wbt_flags(struct rq_wb *rwb, struct bio *bio)
|
|
{
|
|
enum wbt_flags flags = 0;
|
|
|
|
if (!rwb_enabled(rwb))
|
|
return 0;
|
|
|
|
if (bio_op(bio) == REQ_OP_READ) {
|
|
flags = WBT_READ;
|
|
} else if (wbt_should_throttle(bio)) {
|
|
if (current_is_kswapd())
|
|
flags |= WBT_KSWAPD;
|
|
if (bio_op(bio) == REQ_OP_DISCARD)
|
|
flags |= WBT_DISCARD;
|
|
flags |= WBT_TRACKED;
|
|
}
|
|
return flags;
|
|
}
|
|
|
|
static void wbt_cleanup(struct rq_qos *rqos, struct bio *bio)
|
|
{
|
|
struct rq_wb *rwb = RQWB(rqos);
|
|
enum wbt_flags flags = bio_to_wbt_flags(rwb, bio);
|
|
__wbt_done(rqos, flags);
|
|
}
|
|
|
|
/*
|
|
* May sleep, if we have exceeded the writeback limits. Caller can pass
|
|
* in an irq held spinlock, if it holds one when calling this function.
|
|
* If we do sleep, we'll release and re-grab it.
|
|
*/
|
|
static void wbt_wait(struct rq_qos *rqos, struct bio *bio)
|
|
{
|
|
struct rq_wb *rwb = RQWB(rqos);
|
|
enum wbt_flags flags;
|
|
|
|
flags = bio_to_wbt_flags(rwb, bio);
|
|
if (!(flags & WBT_TRACKED)) {
|
|
if (flags & WBT_READ)
|
|
wb_timestamp(rwb, &rwb->last_issue);
|
|
return;
|
|
}
|
|
|
|
__wbt_wait(rwb, flags, bio->bi_opf);
|
|
|
|
if (!blk_stat_is_active(rwb->cb))
|
|
rwb_arm_timer(rwb);
|
|
}
|
|
|
|
static void wbt_track(struct rq_qos *rqos, struct request *rq, struct bio *bio)
|
|
{
|
|
struct rq_wb *rwb = RQWB(rqos);
|
|
rq->wbt_flags |= bio_to_wbt_flags(rwb, bio);
|
|
}
|
|
|
|
static void wbt_issue(struct rq_qos *rqos, struct request *rq)
|
|
{
|
|
struct rq_wb *rwb = RQWB(rqos);
|
|
|
|
if (!rwb_enabled(rwb))
|
|
return;
|
|
|
|
/*
|
|
* Track sync issue, in case it takes a long time to complete. Allows us
|
|
* to react quicker, if a sync IO takes a long time to complete. Note
|
|
* that this is just a hint. The request can go away when it completes,
|
|
* so it's important we never dereference it. We only use the address to
|
|
* compare with, which is why we store the sync_issue time locally.
|
|
*/
|
|
if (wbt_is_read(rq) && !rwb->sync_issue) {
|
|
rwb->sync_cookie = rq;
|
|
rwb->sync_issue = rq->io_start_time_ns;
|
|
}
|
|
}
|
|
|
|
static void wbt_requeue(struct rq_qos *rqos, struct request *rq)
|
|
{
|
|
struct rq_wb *rwb = RQWB(rqos);
|
|
if (!rwb_enabled(rwb))
|
|
return;
|
|
if (rq == rwb->sync_cookie) {
|
|
rwb->sync_issue = 0;
|
|
rwb->sync_cookie = NULL;
|
|
}
|
|
}
|
|
|
|
void wbt_set_write_cache(struct request_queue *q, bool write_cache_on)
|
|
{
|
|
struct rq_qos *rqos = wbt_rq_qos(q);
|
|
if (rqos)
|
|
RQWB(rqos)->wc = write_cache_on;
|
|
}
|
|
|
|
/*
|
|
* Enable wbt if defaults are configured that way
|
|
*/
|
|
void wbt_enable_default(struct request_queue *q)
|
|
{
|
|
struct rq_qos *rqos = wbt_rq_qos(q);
|
|
|
|
/* Throttling already enabled? */
|
|
if (rqos) {
|
|
if (RQWB(rqos)->enable_state == WBT_STATE_OFF_DEFAULT)
|
|
RQWB(rqos)->enable_state = WBT_STATE_ON_DEFAULT;
|
|
return;
|
|
}
|
|
|
|
/* Queue not registered? Maybe shutting down... */
|
|
if (!blk_queue_registered(q))
|
|
return;
|
|
|
|
if (queue_is_mq(q) && IS_ENABLED(CONFIG_BLK_WBT_MQ))
|
|
wbt_init(q);
|
|
}
|
|
EXPORT_SYMBOL_GPL(wbt_enable_default);
|
|
|
|
u64 wbt_default_latency_nsec(struct request_queue *q)
|
|
{
|
|
/*
|
|
* We default to 2msec for non-rotational storage, and 75msec
|
|
* for rotational storage.
|
|
*/
|
|
if (blk_queue_nonrot(q))
|
|
return 2000000ULL;
|
|
else
|
|
return 75000000ULL;
|
|
}
|
|
|
|
static int wbt_data_dir(const struct request *rq)
|
|
{
|
|
const enum req_op op = req_op(rq);
|
|
|
|
if (op == REQ_OP_READ)
|
|
return READ;
|
|
else if (op_is_write(op))
|
|
return WRITE;
|
|
|
|
/* don't account */
|
|
return -1;
|
|
}
|
|
|
|
static void wbt_queue_depth_changed(struct rq_qos *rqos)
|
|
{
|
|
RQWB(rqos)->rq_depth.queue_depth = blk_queue_depth(rqos->q);
|
|
wbt_update_limits(RQWB(rqos));
|
|
}
|
|
|
|
static void wbt_exit(struct rq_qos *rqos)
|
|
{
|
|
struct rq_wb *rwb = RQWB(rqos);
|
|
struct request_queue *q = rqos->q;
|
|
|
|
blk_stat_remove_callback(q, rwb->cb);
|
|
blk_stat_free_callback(rwb->cb);
|
|
kfree(rwb);
|
|
}
|
|
|
|
/*
|
|
* Disable wbt, if enabled by default.
|
|
*/
|
|
void wbt_disable_default(struct request_queue *q)
|
|
{
|
|
struct rq_qos *rqos = wbt_rq_qos(q);
|
|
struct rq_wb *rwb;
|
|
if (!rqos)
|
|
return;
|
|
rwb = RQWB(rqos);
|
|
if (rwb->enable_state == WBT_STATE_ON_DEFAULT) {
|
|
blk_stat_deactivate(rwb->cb);
|
|
rwb->enable_state = WBT_STATE_OFF_DEFAULT;
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(wbt_disable_default);
|
|
|
|
#ifdef CONFIG_BLK_DEBUG_FS
|
|
static int wbt_curr_win_nsec_show(void *data, struct seq_file *m)
|
|
{
|
|
struct rq_qos *rqos = data;
|
|
struct rq_wb *rwb = RQWB(rqos);
|
|
|
|
seq_printf(m, "%llu\n", rwb->cur_win_nsec);
|
|
return 0;
|
|
}
|
|
|
|
static int wbt_enabled_show(void *data, struct seq_file *m)
|
|
{
|
|
struct rq_qos *rqos = data;
|
|
struct rq_wb *rwb = RQWB(rqos);
|
|
|
|
seq_printf(m, "%d\n", rwb->enable_state);
|
|
return 0;
|
|
}
|
|
|
|
static int wbt_id_show(void *data, struct seq_file *m)
|
|
{
|
|
struct rq_qos *rqos = data;
|
|
|
|
seq_printf(m, "%u\n", rqos->id);
|
|
return 0;
|
|
}
|
|
|
|
static int wbt_inflight_show(void *data, struct seq_file *m)
|
|
{
|
|
struct rq_qos *rqos = data;
|
|
struct rq_wb *rwb = RQWB(rqos);
|
|
int i;
|
|
|
|
for (i = 0; i < WBT_NUM_RWQ; i++)
|
|
seq_printf(m, "%d: inflight %d\n", i,
|
|
atomic_read(&rwb->rq_wait[i].inflight));
|
|
return 0;
|
|
}
|
|
|
|
static int wbt_min_lat_nsec_show(void *data, struct seq_file *m)
|
|
{
|
|
struct rq_qos *rqos = data;
|
|
struct rq_wb *rwb = RQWB(rqos);
|
|
|
|
seq_printf(m, "%lu\n", rwb->min_lat_nsec);
|
|
return 0;
|
|
}
|
|
|
|
static int wbt_unknown_cnt_show(void *data, struct seq_file *m)
|
|
{
|
|
struct rq_qos *rqos = data;
|
|
struct rq_wb *rwb = RQWB(rqos);
|
|
|
|
seq_printf(m, "%u\n", rwb->unknown_cnt);
|
|
return 0;
|
|
}
|
|
|
|
static int wbt_normal_show(void *data, struct seq_file *m)
|
|
{
|
|
struct rq_qos *rqos = data;
|
|
struct rq_wb *rwb = RQWB(rqos);
|
|
|
|
seq_printf(m, "%u\n", rwb->wb_normal);
|
|
return 0;
|
|
}
|
|
|
|
static int wbt_background_show(void *data, struct seq_file *m)
|
|
{
|
|
struct rq_qos *rqos = data;
|
|
struct rq_wb *rwb = RQWB(rqos);
|
|
|
|
seq_printf(m, "%u\n", rwb->wb_background);
|
|
return 0;
|
|
}
|
|
|
|
static const struct blk_mq_debugfs_attr wbt_debugfs_attrs[] = {
|
|
{"curr_win_nsec", 0400, wbt_curr_win_nsec_show},
|
|
{"enabled", 0400, wbt_enabled_show},
|
|
{"id", 0400, wbt_id_show},
|
|
{"inflight", 0400, wbt_inflight_show},
|
|
{"min_lat_nsec", 0400, wbt_min_lat_nsec_show},
|
|
{"unknown_cnt", 0400, wbt_unknown_cnt_show},
|
|
{"wb_normal", 0400, wbt_normal_show},
|
|
{"wb_background", 0400, wbt_background_show},
|
|
{},
|
|
};
|
|
#endif
|
|
|
|
static struct rq_qos_ops wbt_rqos_ops = {
|
|
.throttle = wbt_wait,
|
|
.issue = wbt_issue,
|
|
.track = wbt_track,
|
|
.requeue = wbt_requeue,
|
|
.done = wbt_done,
|
|
.cleanup = wbt_cleanup,
|
|
.queue_depth_changed = wbt_queue_depth_changed,
|
|
.exit = wbt_exit,
|
|
#ifdef CONFIG_BLK_DEBUG_FS
|
|
.debugfs_attrs = wbt_debugfs_attrs,
|
|
#endif
|
|
};
|
|
|
|
int wbt_init(struct request_queue *q)
|
|
{
|
|
struct rq_wb *rwb;
|
|
int i;
|
|
int ret;
|
|
|
|
rwb = kzalloc(sizeof(*rwb), GFP_KERNEL);
|
|
if (!rwb)
|
|
return -ENOMEM;
|
|
|
|
rwb->cb = blk_stat_alloc_callback(wb_timer_fn, wbt_data_dir, 2, rwb);
|
|
if (!rwb->cb) {
|
|
kfree(rwb);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
for (i = 0; i < WBT_NUM_RWQ; i++)
|
|
rq_wait_init(&rwb->rq_wait[i]);
|
|
|
|
rwb->rqos.id = RQ_QOS_WBT;
|
|
rwb->rqos.ops = &wbt_rqos_ops;
|
|
rwb->rqos.q = q;
|
|
rwb->last_comp = rwb->last_issue = jiffies;
|
|
rwb->win_nsec = RWB_WINDOW_NSEC;
|
|
rwb->enable_state = WBT_STATE_ON_DEFAULT;
|
|
rwb->wc = 1;
|
|
rwb->rq_depth.default_depth = RWB_DEF_DEPTH;
|
|
|
|
/*
|
|
* Assign rwb and add the stats callback.
|
|
*/
|
|
ret = rq_qos_add(q, &rwb->rqos);
|
|
if (ret)
|
|
goto err_free;
|
|
|
|
blk_stat_add_callback(q, rwb->cb);
|
|
|
|
rwb->min_lat_nsec = wbt_default_latency_nsec(q);
|
|
|
|
wbt_queue_depth_changed(&rwb->rqos);
|
|
wbt_set_write_cache(q, test_bit(QUEUE_FLAG_WC, &q->queue_flags));
|
|
|
|
return 0;
|
|
|
|
err_free:
|
|
blk_stat_free_callback(rwb->cb);
|
|
kfree(rwb);
|
|
return ret;
|
|
|
|
}
|