Commit 5b50bf77 authored by Paolo Bonzini's avatar Paolo Bonzini Committed by Fam Zheng
Browse files

block: make accounting thread-safe 



I'm not trying too hard yet.  Later, with multiqueue support,
this may cause mutex contention or cacheline bouncing.

Cc: Alberto Garcia <berto@igalia.com>
Reviewed-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Message-Id: <20170605123908.18777-20-pbonzini@redhat.com>
Reviewed-by: default avatarAlberto Garcia <berto@igalia.com>
Signed-off-by: default avatarFam Zheng <famz@redhat.com>
parent 9caa6f3d

block/accounting.c

+16 −0
Original line number Diff line number Diff line
@@ -34,6 +34,7 @@ static const int qtest_latency_ns = NANOSECONDS_PER_SECOND / 1000; 


void block_acct_init(BlockAcctStats *stats)

{

    qemu_mutex_init(&stats->lock);

    if (qtest_enabled()) {

        clock_type = QEMU_CLOCK_VIRTUAL;

    }
@@ -52,6 +53,7 @@ void block_acct_cleanup(BlockAcctStats *stats) 
    QSLIST_FOREACH_SAFE(s, &stats->intervals, entries, next) {

        g_free(s);

    }

    qemu_mutex_destroy(&stats->lock);

}



void block_acct_add_interval(BlockAcctStats *stats, unsigned interval_length)
@@ -61,12 +63,15 @@ void block_acct_add_interval(BlockAcctStats *stats, unsigned interval_length) 


    s = g_new0(BlockAcctTimedStats, 1);

    s->interval_length = interval_length;

    s->stats = stats;

    qemu_mutex_lock(&stats->lock);

    QSLIST_INSERT_HEAD(&stats->intervals, s, entries);



    for (i = 0; i < BLOCK_MAX_IOTYPE; i++) {

        timed_average_init(&s->latency[i], clock_type,

                           (uint64_t) interval_length * NANOSECONDS_PER_SECOND);

    }

    qemu_mutex_unlock(&stats->lock);

}



BlockAcctTimedStats *block_acct_interval_next(BlockAcctStats *stats,
@@ -102,6 +107,8 @@ static void block_account_one_io(BlockAcctStats *stats, BlockAcctCookie *cookie, 


    assert(cookie->type < BLOCK_MAX_IOTYPE);



    qemu_mutex_lock(&stats->lock);



    if (failed) {

        stats->failed_ops[cookie->type]++;

    } else {
@@ -117,6 +124,8 @@ static void block_account_one_io(BlockAcctStats *stats, BlockAcctCookie *cookie, 
            timed_average_account(&s->latency[cookie->type], latency_ns);

        }

    }



    qemu_mutex_unlock(&stats->lock);

}



void block_acct_done(BlockAcctStats *stats, BlockAcctCookie *cookie)
@@ -137,18 +146,23 @@ void block_acct_invalid(BlockAcctStats *stats, enum BlockAcctType type) 
     * not.  The reason is that invalid requests are accounted during their

     * submission, therefore there's no actual I/O involved.

     */

    qemu_mutex_lock(&stats->lock);

    stats->invalid_ops[type]++;



    if (stats->account_invalid) {

        stats->last_access_time_ns = qemu_clock_get_ns(clock_type);

    }

    qemu_mutex_unlock(&stats->lock);

}



void block_acct_merge_done(BlockAcctStats *stats, enum BlockAcctType type,

                      int num_requests)

{

    assert(type < BLOCK_MAX_IOTYPE);



    qemu_mutex_lock(&stats->lock);

    stats->merged[type] += num_requests;

    qemu_mutex_unlock(&stats->lock);

}



int64_t block_acct_idle_time_ns(BlockAcctStats *stats)
@@ -163,7 +177,9 @@ double block_acct_queue_depth(BlockAcctTimedStats *stats, 


    assert(type < BLOCK_MAX_IOTYPE);



    qemu_mutex_lock(&stats->stats->lock);

    sum = timed_average_sum(&stats->latency[type], &elapsed);

    qemu_mutex_unlock(&stats->stats->lock);



    return (double) sum / elapsed;

}

include/block/accounting.h

+6 −2
Original line number Diff line number Diff line
@@ -26,8 +26,10 @@ 
#define BLOCK_ACCOUNTING_H



#include "qemu/timed-average.h"

#include "qemu/thread.h"



typedef struct BlockAcctTimedStats BlockAcctTimedStats;

typedef struct BlockAcctStats BlockAcctStats;



enum BlockAcctType {

    BLOCK_ACCT_READ,
@@ -37,12 +39,14 @@ enum BlockAcctType { 
};



struct BlockAcctTimedStats {

    BlockAcctStats *stats;

    TimedAverage latency[BLOCK_MAX_IOTYPE];

    unsigned interval_length; /* in seconds */

    QSLIST_ENTRY(BlockAcctTimedStats) entries;

};



typedef struct BlockAcctStats {

struct BlockAcctStats {

    QemuMutex lock;

    uint64_t nr_bytes[BLOCK_MAX_IOTYPE];

    uint64_t nr_ops[BLOCK_MAX_IOTYPE];

    uint64_t invalid_ops[BLOCK_MAX_IOTYPE];
@@ -53,7 +57,7 @@ typedef struct BlockAcctStats { 
    QSLIST_HEAD(, BlockAcctTimedStats) intervals;

    bool account_invalid;

    bool account_failed;

} BlockAcctStats;

};



typedef struct BlockAcctCookie {

    int64_t bytes;