On 11/08/2012 08:21 PM, Andrew Morton wrote: > On Thu, 8 Nov 2012 17:15:36 +0000 > Christoph Lameter <cl@xxxxxxxxx> wrote: > >> On Wed, 7 Nov 2012, Andrew Morton wrote: >> >>> What's up with kmem_cache_shrink? It's global and exported to modules >>> but its only external caller is some weird and hopelessly poorly >>> documented site down in drivers/acpi/osl.c. slab and slob implement >>> kmem_cache_shrink() *only* for acpi! wtf? Let's work out what acpi is >>> trying to actually do there, then do it properly, then killkillkill! >> >> kmem_cache_shrink is also used internally. Its simply releasing unused >> cached objects. > > Only in slub. It could be removed outright from the others and > simplified in slub. > >>> Secondly, as slab and slub (at least) have the ability to shed cached >>> memory, why aren't they hooked into the core cache-shinking machinery. >>> After all, it's called "shrink_slab"! >> >> Because the core cache shrinking needs the slab caches to free up memory >> from inodes and dentries. We could call kmem_cache_shrink at the end of >> the shrink passes in vmscan. The price would be that the caches would have >> to be repopulated when new allocations occur. > > Well, the shrinker shouldn't strips away all the cache. It will perform > a partial trim, the magnitude of which increases with perceived > external memory pressure. > > AFACIT, this is correct and desirable behaviour for shrinking > slab's internal caches. > I believe calling this from shrink_slab() is not a bad idea at all. If you're all in favour, I'll cook a patch for this soon -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>