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    getrusage(): fill ru_inblock and ru_oublock fields if possible · 6eaeeaba
    Eric Dumazet 提交于
    If CONFIG_TASK_IO_ACCOUNTING is defined, we update io accounting counters for
    each task.
    
    This patch permits reporting of values using the well known getrusage()
    syscall, filling ru_inblock and ru_oublock instead of null values.
    
    As TASK_IO_ACCOUNTING currently counts bytes counts, we approximate blocks
    count doing : nr_blocks = nr_bytes / 512
    
    Example of use :
    ----------------------
    After patch is applied, /usr/bin/time command can now give a good
    approximation of IO that the process had to do.
    
    $ /usr/bin/time grep tototo /usr/include/*
    Command exited with non-zero status 1
    0.00user 0.02system 0:02.11elapsed 1%CPU (0avgtext+0avgdata 0maxresident)k
    24288inputs+0outputs (0major+259minor)pagefaults 0swaps
    
    $ /usr/bin/time dd if=/dev/zero of=/tmp/testfile count=1000
    1000+0 enregistrements lus
    1000+0 enregistrements écrits
    512000 octets (512 kB) copiés, 0,00326601 seconde, 157 MB/s
    0.00user 0.00system 0:00.00elapsed 80%CPU (0avgtext+0avgdata 0maxresident)k
    0inputs+3000outputs (0major+299minor)pagefaults 0swaps
    Signed-off-by: NEric Dumazet <dada1@cosmosbay.com>
    Cc: Oleg Nesterov <oleg@tv-sign.ru>
    Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
    6eaeeaba
fork.c 40.7 KB