Excessive calls to iterate_phdr during exception handling

[Richard Henderson]

On 05/30/2013 04:30 PM, Ryan Johnson wrote:
> Is there a way for libgcc_s to interpose on dlopen/dlclose if (and only if)
> those are present? If so, the wrappers could increment an atomic version
> counter, which would be plenty accurate for invalidating an object header
> cache, without requiring any changes to glibc.

You'll note that we already have a cache, which gets invalidated by changes
to the dlpi_adds and dlpi_subs members of dl_phdr_info.

It's a space-limited LRU cache though, so I don't see a way to reduce the set
of code that must live under the dl_iterate_phdr mutex.


r~