lkml.org 
[lkml]   [2012]   [Jul]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH RESEND] Fix a dead loop in async_synchronize_full()
    On Mon, 09 Jul 2012 15:04:25 +0800
    Li Zhong <zhong@linux.vnet.ibm.com> wrote:

    > This patch tries to fix a dead loop in async_synchronize_full(), which
    > could be seen when preemption is disabled on a single cpu machine.
    >
    > void async_synchronize_full(void)
    > {
    > do {
    > async_synchronize_cookie(next_cookie);
    > } while (!list_empty(&async_running) || !
    > list_empty(&async_pending));
    > }
    >
    > async_synchronize_cookie() calls async_synchronize_cookie_domain() with
    > &async_running as the default domain to synchronize.
    >
    > However, there might be some works in the async_pending list from other
    > domains. On a single cpu system, without preemption, there is no chance
    > for the other works to finish, so async_synchronize_full() enters a dead
    > loop.
    >
    > It seems async_synchronize_full() wants to synchronize all entries in
    > all running lists(domains), so maybe we could just check the entry_count
    > to know whether all works are finished.
    >
    > Currently, async_synchronize_cookie_domain() expects a non-NULL running
    > list ( if NULL, there would be NULL pointer dereference ), so maybe a
    > NULL pointer could be used as an indication for the functions to
    > synchronize all works in all domains.

    The patch is fairly wordwrapped - please fix up your email client.

    More seriously, it does not apply to linux-next due to some fairly
    significant changes which have been sitting in Dan's tree since May.
    What's going on?



    \
     
     \ /
      Last update: 2012-07-12 02:01    [W:0.026 / U:90.780 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site