On 7/16/20 9:27 AM, Joonsoo Kim wrote:
2020년 7월 15일 (수) 오후 5:24, Vlastimil Babka vbabka@suse.cz님이 작성:
/*
- get_page_from_freelist goes through the zonelist trying to allocate
- a page.
@@ -3706,6 +3714,8 @@ get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags, struct pglist_data *last_pgdat_dirty_limit = NULL; bool no_fallback;
current_alloc_flags(gfp_mask, &alloc_flags);I don't see why to move the test here? It will still be executed in the fastpath, if that's what you wanted to avoid.
I want to execute it on the fastpath, too. Reason that I moved it here is that alloc_flags could be reset on slowpath. See the code where __gfp_pfmemalloc_flags() is on. This is the only place that I can apply this option to all the allocation paths at once.
But get_page_from_freelist() might be called multiple times in the slowpath, and also anyone looking for gfp and alloc flags setup will likely not examine this function. I don't see a problem in having it in two places that already deal with alloc_flags setup, as it is now.
Thanks.
retry: /* * Scan zonelist, looking for a zone with enough free. @@ -4339,10 +4349,6 @@ gfp_to_alloc_flags(gfp_t gfp_mask) } else if (unlikely(rt_task(current)) && !in_interrupt()) alloc_flags |= ALLOC_HARDER;
-#ifdef CONFIG_CMA
if (gfp_migratetype(gfp_mask) == MIGRATE_MOVABLE)alloc_flags |= ALLOC_CMA;-#endif
I would just replace this here with: alloc_flags = current_alloc_flags(gfp_mask, alloc_flags);
return alloc_flags;}
@@ -4808,9 +4814,6 @@ static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order, if (should_fail_alloc_page(gfp_mask, order)) return false;
if (IS_ENABLED(CONFIG_CMA) && ac->migratetype == MIGRATE_MOVABLE)*alloc_flags |= ALLOC_CMA;And same here... Ah, I see. current_alloc_flags() should probably take a migratetype parameter instead of gfp_mask then.
return true;}