From: Minchan Kim <minchan@kernel.org> To: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Subject: Re: [RFC][PATCHv2 2/8] zsmalloc: partial page ordering within a fullness_list Date: Tue, 16 Jun 2015 22:19:03 +0900 [thread overview] Message-ID: <20150616131903.GA31387@blaptop> (raw) In-Reply-To: <1433505838-23058-3-git-send-email-sergey.senozhatsky@gmail.com> Hello Sergey, On Fri, Jun 05, 2015 at 09:03:52PM +0900, Sergey Senozhatsky wrote: > We want to see more ZS_FULL pages and less ZS_ALMOST_{FULL, EMPTY} > pages. Put a page with higher ->inuse count first within its > ->fullness_list, which will give us better chances to fill up this > page with new objects (find_get_zspage() return ->fullness_list head > for new object allocation), so some zspages will become > ZS_ALMOST_FULL/ZS_FULL quicker. > > It performs a trivial and cheap ->inuse compare which does not slow > down zsmalloc, and in the worst case it keeps the list pages not in > any particular order, just like we do it now. Fair enough. I think it would be better with small cost and it matches current zsmalloc design which allocates a object from ALMOST_FULL zspage first to reduce memory footprint. Although we uses page->lru to link zspages, it's not lru order so I like your idea. One think I want to say is it doesn't need to be part of this patchset. I hope you gives some data to prove gain and includes it in changelog and resubmit, please. > > A more expensive solution could sort fullness_list by ->inuse count. > > Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> > --- > mm/zsmalloc.c | 12 ++++++++++-- > 1 file changed, 10 insertions(+), 2 deletions(-) > > diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c > index ce3310c..cd37bda 100644 > --- a/mm/zsmalloc.c > +++ b/mm/zsmalloc.c > @@ -658,8 +658,16 @@ static void insert_zspage(struct page *page, struct size_class *class, > return; > > head = &class->fullness_list[fullness]; > - if (*head) > - list_add_tail(&page->lru, &(*head)->lru); > + if (*head) { > + /* > + * We want to see more ZS_FULL pages and less almost > + * empty/full. Put pages with higher ->inuse first. > + */ > + if (page->inuse < (*head)->inuse) > + list_add_tail(&page->lru, &(*head)->lru); > + else > + list_add(&page->lru, &(*head)->lru); > + } > > *head = page; > zs_stat_inc(class, fullness == ZS_ALMOST_EMPTY ? > -- > 2.4.2.387.gf86f31a > -- Kind regards, Minchan Kim
WARNING: multiple messages have this Message-ID (diff)
From: Minchan Kim <minchan@kernel.org> To: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Subject: Re: [RFC][PATCHv2 2/8] zsmalloc: partial page ordering within a fullness_list Date: Tue, 16 Jun 2015 22:19:03 +0900 [thread overview] Message-ID: <20150616131903.GA31387@blaptop> (raw) In-Reply-To: <1433505838-23058-3-git-send-email-sergey.senozhatsky@gmail.com> Hello Sergey, On Fri, Jun 05, 2015 at 09:03:52PM +0900, Sergey Senozhatsky wrote: > We want to see more ZS_FULL pages and less ZS_ALMOST_{FULL, EMPTY} > pages. Put a page with higher ->inuse count first within its > ->fullness_list, which will give us better chances to fill up this > page with new objects (find_get_zspage() return ->fullness_list head > for new object allocation), so some zspages will become > ZS_ALMOST_FULL/ZS_FULL quicker. > > It performs a trivial and cheap ->inuse compare which does not slow > down zsmalloc, and in the worst case it keeps the list pages not in > any particular order, just like we do it now. Fair enough. I think it would be better with small cost and it matches current zsmalloc design which allocates a object from ALMOST_FULL zspage first to reduce memory footprint. Although we uses page->lru to link zspages, it's not lru order so I like your idea. One think I want to say is it doesn't need to be part of this patchset. I hope you gives some data to prove gain and includes it in changelog and resubmit, please. > > A more expensive solution could sort fullness_list by ->inuse count. > > Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> > --- > mm/zsmalloc.c | 12 ++++++++++-- > 1 file changed, 10 insertions(+), 2 deletions(-) > > diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c > index ce3310c..cd37bda 100644 > --- a/mm/zsmalloc.c > +++ b/mm/zsmalloc.c > @@ -658,8 +658,16 @@ static void insert_zspage(struct page *page, struct size_class *class, > return; > > head = &class->fullness_list[fullness]; > - if (*head) > - list_add_tail(&page->lru, &(*head)->lru); > + if (*head) { > + /* > + * We want to see more ZS_FULL pages and less almost > + * empty/full. Put pages with higher ->inuse first. > + */ > + if (page->inuse < (*head)->inuse) > + list_add_tail(&page->lru, &(*head)->lru); > + else > + list_add(&page->lru, &(*head)->lru); > + } > > *head = page; > zs_stat_inc(class, fullness == ZS_ALMOST_EMPTY ? > -- > 2.4.2.387.gf86f31a > -- Kind regards, Minchan Kim -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2015-06-16 13:19 UTC|newest] Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-06-05 12:03 [RFC][PATCHv2 0/8] introduce automatic pool compaction Sergey Senozhatsky 2015-06-05 12:03 ` Sergey Senozhatsky 2015-06-05 12:03 ` [RFC][PATCHv2 1/8] zsmalloc: drop unused variable `nr_to_migrate' Sergey Senozhatsky 2015-06-05 12:03 ` Sergey Senozhatsky 2015-06-05 12:03 ` [RFC][PATCHv2 2/8] zsmalloc: partial page ordering within a fullness_list Sergey Senozhatsky 2015-06-05 12:03 ` Sergey Senozhatsky 2015-06-16 13:19 ` Minchan Kim [this message] 2015-06-16 13:19 ` Minchan Kim 2015-06-16 14:30 ` Sergey Senozhatsky 2015-06-16 14:30 ` Sergey Senozhatsky 2015-06-05 12:03 ` [RFC][PATCHv2 3/8] zsmalloc: lower ZS_ALMOST_FULL waterline Sergey Senozhatsky 2015-06-05 12:03 ` Sergey Senozhatsky 2015-06-16 13:37 ` Minchan Kim 2015-06-16 13:37 ` Minchan Kim 2015-06-16 14:35 ` Sergey Senozhatsky 2015-06-16 14:35 ` Sergey Senozhatsky 2015-06-05 12:03 ` [RFC][PATCHv2 4/8] zsmalloc: always keep per-class stats Sergey Senozhatsky 2015-06-05 12:03 ` Sergey Senozhatsky 2015-06-05 12:03 ` [RFC][PATCHv2 5/8] zsmalloc: introduce zs_can_compact() function Sergey Senozhatsky 2015-06-05 12:03 ` Sergey Senozhatsky 2015-06-16 14:19 ` Minchan Kim 2015-06-16 14:19 ` Minchan Kim 2015-06-16 14:41 ` Sergey Senozhatsky 2015-06-16 14:41 ` Sergey Senozhatsky 2015-06-05 12:03 ` [RFC][PATCHv2 6/8] zsmalloc: cosmetic compaction code adjustments Sergey Senozhatsky 2015-06-05 12:03 ` Sergey Senozhatsky 2015-06-05 12:03 ` [RFC][PATCHv2 7/8] zsmalloc/zram: move `num_migrated' to zs_pool Sergey Senozhatsky 2015-06-05 12:03 ` Sergey Senozhatsky 2015-06-05 12:03 ` [RFC][PATCHv2 8/8] zsmalloc: register a shrinker to trigger auto-compaction Sergey Senozhatsky 2015-06-05 12:03 ` Sergey Senozhatsky 2015-06-16 14:47 ` Minchan Kim 2015-06-16 14:47 ` Minchan Kim 2015-06-16 15:45 ` Sergey Senozhatsky 2015-06-16 15:45 ` Sergey Senozhatsky 2015-06-18 1:50 ` Minchan Kim 2015-06-18 1:50 ` Minchan Kim 2015-06-18 2:41 ` Sergey Senozhatsky 2015-06-18 2:41 ` Sergey Senozhatsky 2015-06-18 3:01 ` Sergey Senozhatsky 2015-06-18 3:01 ` Sergey Senozhatsky 2015-06-18 3:46 ` Minchan Kim 2015-06-18 3:46 ` Minchan Kim 2015-06-18 3:39 ` Minchan Kim 2015-06-18 3:39 ` Minchan Kim 2015-06-18 3:58 ` Sergey Senozhatsky 2015-06-18 3:58 ` Sergey Senozhatsky 2015-06-17 7:11 ` Sergey Senozhatsky 2015-06-17 7:11 ` Sergey Senozhatsky 2015-06-10 0:04 ` [RFC][PATCHv2 0/8] introduce automatic pool compaction Minchan Kim 2015-06-10 0:04 ` Minchan Kim 2015-06-10 0:07 ` Sergey Senozhatsky 2015-06-10 0:07 ` Sergey Senozhatsky
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