Not with apr_palloc() or anything that calls apr_palloc (eg apr_pcalloc, et.al...)
> On Feb 20, 2017, at 10:15 AM, Stefan Eissing <stefan.eiss...@greenbytes.de> > wrote: > >> >> Am 20.02.2017 um 16:08 schrieb Jim Jagielski <j...@jagunet.com>: >> >> Again, this would ONLY happen if the underlying allocator has >> a mutex! > > But isn't that now true for all conn_rec->pool and thus r->pool and > c->bucket_alloc etc? > >> >>> On Feb 20, 2017, at 10:06 AM, Branko Čibej <br...@apache.org> wrote: >>> >>> On 20.02.2017 15:55, Jim Jagielski wrote: >>>>> On Feb 20, 2017, at 9:51 AM, Stefan Eissing >>>>> <stefan.eiss...@greenbytes.de> wrote: >>>>> >>>>>> Am 20.02.2017 um 15:16 schrieb Jim Jagielski <j...@jagunet.com>: >>>>>> >>>>>> The below got me thinking... >>>>>> >>>>>> Right now, the pool allocator mutex is only used when, well, >>>>>> allocator_alloc() is called, which means that sometimes >>>>>> apr_palloc(), for example, can be thread-safeish and sometimes >>>>>> not, depending on whether or not the active node has enough >>>>>> space. >>>>>> >>>>>> For 1.6 and later, it might be nice to actually protect the >>>>>> adjustment of the active node, et.al. to, if a mutex is present, >>>>>> always be thread-safe... that is, always when we "alloc" memory, >>>>>> even when/if we do/don't called allocator_alloc(). >>>>>> >>>>>> Thoughts? >>>>> So, apr_p*alloc() calls would be thread-safe if a mutex is set in >>>>> the underlying allocator? Hmm, at what cost? would be my question. >>>>> >>>> The cost would be the time spent on a lock on each call to apr_palloc() >>>> or anything that *uses* apr_palloc(). >>>> >>>> The idea being that if the underlying allocator has a mutex, the >>>> assumption should be that the pool using that allocator "wants" >>>> or "expects" to be thread-safe... It seems an easy way to create >>>> thread-safe APR pools, but I could be missing something crucial >>>> here. >>>> >>>> Of course, if the allocator does NOT have a mutex, no change and >>>> no cost. >>> >>> >>> I've always understood that creating subpools is thread safe iff the >>> allocator has a mutex, but allocating from any single pool is not, by >>> definition. Acquiring a mutex for every apr_palloc() seems like a good >>> way to throw away pools' speed advantage compared to malloc(). >>> >>> -- Brane >> > > Stefan Eissing > > <green/>bytes GmbH > Hafenstrasse 16 > 48155 Münster > www.greenbytes.de
