Messages in this thread | | | Date | Thu, 19 Oct 2023 14:29:52 +0800 | Subject | Re: [PATCH 2/2] mm: multi-gen lru: fix stat count | From | Huan Yang <> |
| |
在 2023/10/19 10:39, Yu Zhao 写道: > On Wed, Oct 18, 2023 at 8:17 PM Huan Yang <link@vivo.com> wrote: >> Hi Yu Zhao, >> >> Thanks for your reply. >> >> 在 2023/10/19 0:21, Yu Zhao 写道: >>> On Wed, Oct 18, 2023 at 2:22 AM Huan Yang <link@vivo.com> wrote: >>>> For multi-gen lru reclaim in evict_folios, like shrink_inactive_list, >>>> gather folios which isolate to reclaim, and invoke shirnk_folio_list. >>>> >>>> But, when complete shrink, it not gather shrink reclaim stat into sc, >>>> we can't get info like nr_dirty\congested in reclaim, and then >>>> control writeback, dirty number and mark as LRUVEC_CONGESTED, or >>>> just bpf trace shrink and get correct sc stat. >>>> >>>> This patch fix this by simple copy code from shrink_inactive_list when >>>> end of shrink list. >>> MGLRU doesn't try to write back dirt file pages in the reclaim path -- >>> it filters them out in sort_folio() and leaves them to the page >> Nice to know this, sort_folio() filters some folio indeed. >> But, I want to know, if we touch some folio in shrink_folio_list(), may some >> folio become dirty or writeback even if sort_folio() filter then? > Good question: in that case MGLRU still doesn't try to write those > folios back because isolate_folio() cleared PG_reclaim and > shrink_folio_list() checks PG_reclaim:
Thank you too much. So, MGLRU have many diff between typic LRU reclaim. So, why don't offer MGLRU a own shrink path to avoid so many check of folio? And more think, it's nice to assign a anon/file reclaim hook into anon_vma/address_space? (Each folio, have their own shrink path, don't try check path if it no need.)
> > if (folio_test_dirty(folio)) { > /* > * Only kswapd can writeback filesystem folios > * to avoid risk of stack overflow. But avoid > * injecting inefficient single-folio I/O into > * flusher writeback as much as possible: only > * write folios when we've encountered many > * dirty folios, and when we've already scanned > * the rest of the LRU for clean folios and see > * the same dirty folios again (with the reclaim > * flag set). > */ > if (folio_is_file_lru(folio) && > (!current_is_kswapd() || > !folio_test_reclaim(folio) || > !test_bit(PGDAT_DIRTY, &pgdat->flags))) { Thanks
| |