[PATCH] lowmemorykiller: prevent multiple instances of low memory killer

Dolkow, Snild Snild.Dolkow at sonymobile.com
Mon Apr 15 13:38:08 UTC 2013

>Where is lowmem_shrink called from?  I only see shrink called from the
>bcache sysfs handler __bch_cache_set().  The return value isn't checked
>Up to now this function has only returns positive numbers.
>There isn't a place which check LMK_BUSY so maybe it's best to just
>return zero?

Hey Dan,

lowmem_shrink is assigned to a shrinker struct (include/linux/shrinker.h) and called in do_shrinker_shrink() in mm/vmscan.c. That, in turn, is called and checked in a few places in vmscan.c.
>From the comments in shrinker.h: 
"It should return the number of objects which remain in the cache. If it returns -1, it means it cannot do any scanning at this time (eg. there is a risk of deadlock). The callback must not return -1 if nr_to_scan is zero."


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