> I need to do lot of small allocations (around 70-80 bytes) from a > critical region > while holding a spinlock. Total number of such allocation could go > upto tens of > thousands in few hours. So all these allocations use GFP_ATOMIC flag > instead of > GFP_KERNEL. As per my understanding, GFP_ATOMIC can never fail, and I > dont > want my allocations to fail. But this could be a bad idea right? Using > GFP_ATOMIC > for all these allocations? GFP_ATOMIC is ideal for situations while using a spinlock or in interrupt context or in places like BH - softirqs and tasklets) as long as you dont want to block or sleep. On the other hand GPF_KERNEL could block. > Is GFP_NOWAIT | GFP_KERNEL guarantee that? > > Is ( GFP_NOWAIT | GFP_KERNEL ) == ( GFP_ATOMIC - dont access emergency > pools)? Not sure if you can do something like this. > I think GFP_KERNEL | GFP_NOWAIT will solve my issue, what say? http://lxr.linux.no/#linux+v2.6.31/include/linux/gfp.h#L41 GFP_ATOMIC is __GFP_WAIT unset while using allocation from the resource pool. So GFP_NOWAIT would be (GFP_ATOMIC & ~__GFP_HIGH) now not allocating from the pool and wait not set. But GFP_KERNEL does include a _GFP_WAIT which may not work. look into _GP_NOMEMALLOC - if you dont want to use memory pool. -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
