Messages in this thread | | | Date | Tue, 8 Mar 2022 20:06:45 -0500 | Subject | Re: [PATCH] mm/list_lru: Optimize memcg_drain_list_lru_node() | From | Waiman Long <> |
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On 3/8/22 19:50, Waiman Long wrote: > On 3/8/22 19:17, Roman Gushchin wrote: >> On Tue, Mar 08, 2022 at 10:41:38AM -0500, Waiman Long wrote: >>> On 3/7/22 23:39, Roman Gushchin wrote: >>>> On Mon, Mar 07, 2022 at 10:30:09PM -0500, Waiman Long wrote: >>>>> Since commit 2c80cd57c743 ("mm/list_lru.c: fix list_lru_count_node() >>>>> to be race free"), we are tracking the total number of lru >>>>> entries in a list_lru_node in its nr_items field. In the case of >>>>> memcg_drain_list_lru_node(), there is nothing to be done if nr_items >>>>> is 0. We don't even need to take the nlru->lock as no new lru entry >>>>> could be added by a racing list_lru_add() to the draining src_idx >>>>> memcg >>>>> at this point. >>>>> >>>>> Signed-off-by: Waiman Long <longman@redhat.com> >>>> Hi Waiman! >>>> >>>> The patch makes total sense to me, however it needs to be rebased >>>> at least >>>> on top of "mm: list_lru: rename memcg_drain_all_list_lrus to >>>> memcg_reparent_list_lrus". >>>> >>>> Thanks! >>>> >>>> >>> This patch was based on the current linux-next tree which includes >>> commit >>> ff221bc26bdd ("mm: list_lru: rename memcg_drain_all_list_lrus to >>> memcg_reparent_list_lrus"). I do remember to double-check linux-next >>> before >>> sending this patch out. In fact, the same patch can be applied to >>> both linux >>> and linux-next tree without problem. >> I'm looking at the mm tree (https://github.com/hnaz/linux-mm.git) and >> clearly >> see that commit "mm: list_lru: rename memcg_drain_all_list_lrus to >> memcg_reparent_list_lrus" eliminated the function with the name >> memcg_drain_list_lru_node(), which your patch is touching. >> Currently the function is located in list_lru.c and is named >> memcg_reparent_list_lru_node(). >> >> linux-next is sometimes a bit behind the mm tree. > > Oh, you are right. I will rebase the patch based on linux-mm. > > Thanks for the suggestion.
The patch was originally based on the linux tree. Then I applied it onto linux-next without any issue. Unfortunately, I failed to notice that the hunk was applied to memcg_reparent_list_lru_node() without realizing that it is the new name for the old memcg_drain_list_lru_node(). The linux-next tree that I used does have all the necessary patches.
Cheers, Longman
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