From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
Dan Streetman <ddstreet@ieee.org>,
Vitaly Wool <vitalywool@gmail.com>,
Minchan Kim <minchan@kernel.org>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
LKML <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>
Subject: Re: [PATCH 0/3] allow zram to use zbud as underlying allocator
Date: Thu, 17 Sep 2015 18:19:56 +0900 [thread overview]
Message-ID: <20150917091956.GA4171@swordfish> (raw)
In-Reply-To: <55FA5BFE.6010605@suse.cz>
On (09/17/15 08:21), Vlastimil Babka wrote:
> On 09/15/2015 06:22 AM, Sergey Senozhatsky wrote:
> >On (09/15/15 00:08), Dan Streetman wrote:
> >[..]
> >
> >correct. a bit of internals: we don't scan all the zspages every
> >time. each class has stats for allocated used objects, allocated
> >used objects, etc. so we 'compact' only classes that can be
> >compacted:
> >
> > static unsigned long zs_can_compact(struct size_class *class)
> > {
> > unsigned long obj_wasted;
> >
> > obj_wasted = zs_stat_get(class, OBJ_ALLOCATED) -
> > zs_stat_get(class, OBJ_USED);
> >
> > obj_wasted /= get_maxobj_per_zspage(class->size,
> > class->pages_per_zspage);
> >
> > return obj_wasted * class->pages_per_zspage;
> > }
> >
> >if we can free any zspages (which is at least one page), then we
> >attempt to do so.
> >
> >is compaction the root cause of the symptoms Vitaly observe?
>
> He mentioned the "compact_stalls" counter which in /proc/vmstat is for the
> traditional physical memory compaction, not the zsmalloc-specific one. Which
> would imply high-order allocations. Does zsmalloc try them first before
> falling back to the order-0 zspages linked together manually?
each zspage is a bunch (pages_per_zspage) of alloc_page() calls
for (i = 0; i < class->pages_per_zspage; i++) {
struct page *page;
page = alloc_page(flags);
if (!page)
goto cleanup;
INIT_LIST_HEAD(&page->lru);
if (i == 0) { /* first page */
SetPagePrivate(page);
set_page_private(page, 0);
first_page = page;
first_page->inuse = 0;
}
if (i == 1)
set_page_private(first_page, (unsigned long)page);
if (i >= 1)
set_page_private(page, (unsigned long)first_page);
if (i >= 2)
list_add(&page->lru, &prev_page->lru);
if (i == class->pages_per_zspage - 1) /* last page */
SetPagePrivate2(page);
prev_page = page;
}
-ss
WARNING: multiple messages have this Message-ID (diff)
From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
Dan Streetman <ddstreet@ieee.org>,
Vitaly Wool <vitalywool@gmail.com>,
Minchan Kim <minchan@kernel.org>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
LKML <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>
Subject: Re: [PATCH 0/3] allow zram to use zbud as underlying allocator
Date: Thu, 17 Sep 2015 18:19:56 +0900 [thread overview]
Message-ID: <20150917091956.GA4171@swordfish> (raw)
In-Reply-To: <55FA5BFE.6010605@suse.cz>
On (09/17/15 08:21), Vlastimil Babka wrote:
> On 09/15/2015 06:22 AM, Sergey Senozhatsky wrote:
> >On (09/15/15 00:08), Dan Streetman wrote:
> >[..]
> >
> >correct. a bit of internals: we don't scan all the zspages every
> >time. each class has stats for allocated used objects, allocated
> >used objects, etc. so we 'compact' only classes that can be
> >compacted:
> >
> > static unsigned long zs_can_compact(struct size_class *class)
> > {
> > unsigned long obj_wasted;
> >
> > obj_wasted = zs_stat_get(class, OBJ_ALLOCATED) -
> > zs_stat_get(class, OBJ_USED);
> >
> > obj_wasted /= get_maxobj_per_zspage(class->size,
> > class->pages_per_zspage);
> >
> > return obj_wasted * class->pages_per_zspage;
> > }
> >
> >if we can free any zspages (which is at least one page), then we
> >attempt to do so.
> >
> >is compaction the root cause of the symptoms Vitaly observe?
>
> He mentioned the "compact_stalls" counter which in /proc/vmstat is for the
> traditional physical memory compaction, not the zsmalloc-specific one. Which
> would imply high-order allocations. Does zsmalloc try them first before
> falling back to the order-0 zspages linked together manually?
each zspage is a bunch (pages_per_zspage) of alloc_page() calls
for (i = 0; i < class->pages_per_zspage; i++) {
struct page *page;
page = alloc_page(flags);
if (!page)
goto cleanup;
INIT_LIST_HEAD(&page->lru);
if (i == 0) { /* first page */
SetPagePrivate(page);
set_page_private(page, 0);
first_page = page;
first_page->inuse = 0;
}
if (i == 1)
set_page_private(first_page, (unsigned long)page);
if (i >= 1)
set_page_private(page, (unsigned long)first_page);
if (i >= 2)
list_add(&page->lru, &prev_page->lru);
if (i == class->pages_per_zspage - 1) /* last page */
SetPagePrivate2(page);
prev_page = page;
}
-ss
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next prev parent reply other threads:[~2015-09-17 9:21 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-14 13:49 [PATCH 0/3] allow zram to use zbud as underlying allocator Vitaly Wool
2015-09-14 13:49 ` Vitaly Wool
2015-09-14 13:50 ` [PATCH 1/3] zram: make max_zpage_size configurable Vitaly Wool
2015-09-14 13:50 ` Vitaly Wool
2015-09-15 1:00 ` Sergey Senozhatsky
2015-09-15 1:00 ` Sergey Senozhatsky
2015-09-15 7:18 ` Vitaly Wool
2015-09-15 7:38 ` Sergey Senozhatsky
2015-09-15 7:38 ` Sergey Senozhatsky
2015-09-15 5:42 ` Dan Streetman
2015-09-15 5:42 ` Dan Streetman
2015-09-15 6:08 ` Sergey Senozhatsky
2015-09-15 6:08 ` Sergey Senozhatsky
2015-09-14 13:51 ` [PATCH 2/3] zpool/zsmalloc/zbud: align on interfaces Vitaly Wool
2015-09-14 13:51 ` Vitaly Wool
2015-09-15 1:06 ` Sergey Senozhatsky
2015-09-15 1:06 ` Sergey Senozhatsky
2015-09-15 5:09 ` Dan Streetman
2015-09-15 5:09 ` Dan Streetman
2015-09-14 13:55 ` [PATCH 3/3] zram: use common zpool interface Vitaly Wool
2015-09-14 13:55 ` Vitaly Wool
2015-09-15 1:12 ` Sergey Senozhatsky
2015-09-15 1:12 ` Sergey Senozhatsky
2015-09-15 6:03 ` Dan Streetman
2015-09-15 6:03 ` Dan Streetman
2015-09-14 14:01 ` [PATCH 0/3] allow zram to use zbud as underlying allocator Vlastimil Babka
2015-09-14 14:01 ` Vlastimil Babka
2015-09-14 14:12 ` Vitaly Wool
2015-09-14 14:12 ` Vitaly Wool
2015-09-14 14:14 ` Vlastimil Babka
2015-09-14 14:14 ` Vlastimil Babka
2015-09-15 4:08 ` Dan Streetman
2015-09-15 4:08 ` Dan Streetman
2015-09-15 4:22 ` Sergey Senozhatsky
2015-09-15 4:22 ` Sergey Senozhatsky
2015-09-17 6:21 ` Vlastimil Babka
2015-09-17 6:21 ` Vlastimil Babka
2015-09-17 9:19 ` Sergey Senozhatsky [this message]
2015-09-17 9:19 ` Sergey Senozhatsky
2015-09-15 0:49 ` Sergey Senozhatsky
2015-09-15 0:49 ` Sergey Senozhatsky
2015-09-15 6:13 ` Minchan Kim
2015-09-15 6:13 ` Minchan Kim
2015-09-25 9:54 ` Vitaly Wool
2015-09-25 9:54 ` Vitaly Wool
2015-09-30 7:52 ` Minchan Kim
2015-09-30 7:52 ` Minchan Kim
2015-09-30 8:01 ` Vitaly Wool
2015-09-30 8:01 ` Vitaly Wool
2015-09-30 8:13 ` Minchan Kim
2015-09-30 8:13 ` Minchan Kim
2015-09-30 8:18 ` Vitaly Wool
2015-09-30 8:18 ` Vitaly Wool
2015-09-30 15:37 ` Vlastimil Babka
2015-09-30 15:37 ` Vlastimil Babka
2015-09-30 15:46 ` Vitaly Wool
2015-09-30 15:46 ` Vitaly Wool
2015-10-01 7:52 ` Vlastimil Babka
2015-10-01 7:52 ` Vlastimil Babka
2015-10-10 9:33 ` Vitaly Wool
2015-10-10 9:33 ` Vitaly Wool
2015-10-14 13:28 ` Vlastimil Babka
2015-10-14 13:28 ` Vlastimil Babka
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