make_magcache() uses blocking malloc() while holding slab_cache_lock spinlock

[Jakub Jermář]

When called from slab_enable_cpucache(), make_magcache() uses blocking malloc() while holding slab_cache_lock spinlock.

[Jakub Jermář]

slab_enable_cpucache() is called only once during system start-up and since magazines are just an optimization, we can probably afford to call malloc() from make_magcache() in a non-blocking mode and gracefully fail make_magcache() if no memory is allocated.

make_magcache() is called also from slab_cache_create() and since all caches are created during system startup, we can apply the same strategy as above, print a warning and possibly modify make_magcache() to signal the failure via a return value.

Note that if we cannot allocate memory this early during system startup, there is already something wrong with the system and the system will hardly boot successfully anyway.

[Jakub Jermář]

Fixed in changeset:head,416.