4 messages, 2 authors, 2016-02-25 · open the first message on its own page
From: priyaranjan <hidden>
Date: 2016-02-25 06:07:32
Hello All, Do you have any idea of a situation where we would need mutex and spinlock to be locked together? I think there is an example for this in Linux kernel. Can anyone help me? Regards, Priyaranjan -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.kernelnewbies.org/pipermail/kernelnewbies/attachments/20160225/ef499e8c/attachment.html
From: Devesh Sharma <hidden>
Date: 2016-02-25 09:23:43
Hi In running kernel there are many places you can look to get the usage. But the bottom line is * You can take a spinlock under a mutex. e.g. mutex_lock--->spinlock-----critical section-----spinunlock--->mutex_unlock. * You can not take a mutex under a spinlock. e.g. spinlock--->mutex_lock -----critical section ....mutex_unlock---->spinunlock is not allowed. On Thu, Feb 25, 2016 at 11:37 AM, priyaranjan [off-list ref] wrote:
Hello All, Do you have any idea of a situation where we would need mutex and spinlock to be locked together? I think there is an example for this in Linux kernel. Can anyone help me? Regards, Priyaranjan _______________________________________________ Kernelnewbies mailing list Kernelnewbies at kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
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From: priyaranjan <hidden>
Date: 2016-02-25 10:12:24
On Thu, Feb 25, 2016 at 2:53 PM, Devesh Sharma [off-list ref] wrote: Hi
In running kernel there are many places you can look to get the usage. But
the bottom line is Can you tell me the specific use case? or give me the file name/driver where this is used.
* You can take a spinlock under a mutex. e.g.
mutex_lock--->spinlock-----critical section-----spinunlock--->mutex_unlock.
* You can not take a mutex under a spinlock. e.g. spinlock--->mutex_lock
-----critical section ....mutex_unlock---->spinunlock is not allowed. On Thu, Feb 25, 2016 at 11:37 AM, priyaranjan [off-list ref] wrote: Hello All, Do you have any idea of a situation where we would need mutex and spinlock to be locked together? I think there is an example for this in Linux kernel. Can anyone help me? Regards, Priyaranjan _______________________________________________ Kernelnewbies mailing list Kernelnewbies at kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.kernelnewbies.org/pipermail/kernelnewbies/attachments/20160225/7dc433fa/attachment.html
From: Devesh Sharma <hidden>
Date: 2016-02-25 10:27:49
Check this out:
drivers/infiniband/core/cache.c
function: ib_cache_gid_add
Line: 338
mutex_lock(&table->lock);
write_lock_irq(&table->rwlock);
.
.
.
.
write_unlock_irq(&table->rwlock);
mutex_unlock(&table->lock);
On Thu, Feb 25, 2016 at 3:42 PM, priyaranjan [off-list ref]
wrote:
quoted
On Thu, Feb 25, 2016 at 2:53 PM, Devesh Sharma [off-list ref]wrote:quoted
Hiquoted
In running kernel there are many places you can look to get the usage.But the bottom line is Can you tell me the specific use case? or give me the file name/driver where this is used.quoted
* You can take a spinlock under a mutex. e.g.mutex_lock--->spinlock-----critical section-----spinunlock--->mutex_unlock.quoted
* You can not take a mutex under a spinlock. e.g. spinlock--->mutex_lock-----critical section ....mutex_unlock---->spinunlock is not allowed. On Thu, Feb 25, 2016 at 11:37 AM, priyaranjan [off-list ref] wrote: Hello All, Do you have any idea of a situation where we would need mutex and spinlock to be locked together? I think there is an example for this in Linux kernel. Can anyone help me? Regards, Priyaranjan _______________________________________________ Kernelnewbies mailing list Kernelnewbies at kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
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