On Wed 29-11-17 09:17:34, Waiman Long wrote: > The list_lru_del() function removes the given item from the LRU list. > The operation looks simple, but it involves writing into the cachelines > of the two neighboring list entries in order to get the deletion done. > That can take a while if the cachelines aren't there yet, thus > prolonging the lock hold time. > > To reduce the lock hold time, the cachelines of the two neighboring > list entries are now prefetched before acquiring the list_lru_node's > lock. > > Using a multi-threaded test program that created a large number > of dentries and then killed them, the execution time was reduced > from 38.5s to 36.6s after applying the patch on a 2-socket 36-core > 72-thread x86-64 system. > > Signed-off-by: Waiman Long <longman@xxxxxxxxxx> The patch still seems to be in the mmotm tree while it breaks compilation. At least m32r defconfig complains with mm/list_lru.c: In function 'list_lru_del': mm/list_lru.c:141:2: error: implicit declaration of function 'prefetchw' [-Werror=implicit-function-declaration] prefetchw(item->prev); It also seems that there is no general agreement in the patch. Andrew, do you plan to keep it? -- Michal Hocko SUSE Labs -- 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>
