From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
To: Minchan Kim <minchan@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
jlayton@poochiereds.net, bfields@fieldses.org,
Vlastimil Babka <vbabka@suse.cz>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
koct9i@gmail.com, aquini@redhat.com,
virtualization@lists.linux-foundation.org,
Mel Gorman <mgorman@suse.de>, Hugh Dickins <hughd@google.com>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Rik van Riel <riel@redhat.com>,
rknize@motorola.com, Gioh Kim <gi-oh.kim@profitbricks.com>,
Sangseok Lee <sangseok.lee@lge.com>,
Chan Gyun Jeong <chan.jeong@lge.com>,
Al Viro <viro@ZenIV.linux.org.uk>,
YiPing Xu <xuyiping@hisilicon.com>
Subject: Re: [PATCH v3 08/16] zsmalloc: squeeze freelist into page->mapping
Date: Mon, 18 Apr 2016 00:56:21 +0900 [thread overview]
Message-ID: <20160417155621.GE575@swordfish> (raw)
In-Reply-To: <1459321935-3655-9-git-send-email-minchan@kernel.org>
Hello,
On (03/30/16 16:12), Minchan Kim wrote:
[..]
> +static void objidx_to_page_and_offset(struct size_class *class,
> + struct page *first_page,
> + unsigned long obj_idx,
> + struct page **obj_page,
> + unsigned long *offset_in_page)
> {
> - unsigned long obj;
> + int i;
> + unsigned long offset;
> + struct page *cursor;
> + int nr_page;
>
> - if (!page) {
> - VM_BUG_ON(obj_idx);
> - return NULL;
> - }
> + offset = obj_idx * class->size;
so we already know the `offset' before we call objidx_to_page_and_offset(),
thus we can drop `struct size_class *class' and `obj_idx', and pass
`long obj_offset' (which is `obj_idx * class->size') instead, right?
we also _may be_ can return `cursor' from the function.
static struct page *objidx_to_page_and_offset(struct page *first_page,
unsigned long obj_offset,
unsigned long *offset_in_page);
this can save ~20 instructions, which is not so terrible for a hot path
like obj_malloc(). what do you think?
well, seems that `unsigned long *offset_in_page' can be calculated
outside of this function too, it's basically
*offset_in_page = (obj_idx * class->size) & ~PAGE_MASK;
so we don't need to supply it to this function, nor modify it there.
which can save ~40 instructions on my system. does this sound silly?
-ss
> + cursor = first_page;
> + nr_page = offset >> PAGE_SHIFT;
>
> - obj = page_to_pfn(page) << OBJ_INDEX_BITS;
> - obj |= ((obj_idx) & OBJ_INDEX_MASK);
> - obj <<= OBJ_TAG_BITS;
> + *offset_in_page = offset & ~PAGE_MASK;
> +
> + for (i = 0; i < nr_page; i++)
> + cursor = get_next_page(cursor);
>
> - return (void *)obj;
> + *obj_page = cursor;
> }
-ss
WARNING: multiple messages have this Message-ID (diff)
From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
To: Minchan Kim <minchan@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
jlayton@poochiereds.net, bfields@fieldses.org,
Vlastimil Babka <vbabka@suse.cz>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
koct9i@gmail.com, aquini@redhat.com,
virtualization@lists.linux-foundation.org,
Mel Gorman <mgorman@suse.de>, Hugh Dickins <hughd@google.com>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Rik van Riel <riel@redhat.com>,
rknize@motorola.com, Gioh Kim <gi-oh.kim@profitbricks.com>,
Sangseok Lee <sangseok.lee@lge.com>,
Chan Gyun Jeong <chan.jeong@lge.com>,
Al Viro <viro@ZenIV.linux.org.uk>,
YiPing Xu <xuyiping@hisilicon.com>
Subject: Re: [PATCH v3 08/16] zsmalloc: squeeze freelist into page->mapping
Date: Mon, 18 Apr 2016 00:56:21 +0900 [thread overview]
Message-ID: <20160417155621.GE575@swordfish> (raw)
In-Reply-To: <1459321935-3655-9-git-send-email-minchan@kernel.org>
Hello,
On (03/30/16 16:12), Minchan Kim wrote:
[..]
> +static void objidx_to_page_and_offset(struct size_class *class,
> + struct page *first_page,
> + unsigned long obj_idx,
> + struct page **obj_page,
> + unsigned long *offset_in_page)
> {
> - unsigned long obj;
> + int i;
> + unsigned long offset;
> + struct page *cursor;
> + int nr_page;
>
> - if (!page) {
> - VM_BUG_ON(obj_idx);
> - return NULL;
> - }
> + offset = obj_idx * class->size;
so we already know the `offset' before we call objidx_to_page_and_offset(),
thus we can drop `struct size_class *class' and `obj_idx', and pass
`long obj_offset' (which is `obj_idx * class->size') instead, right?
we also _may be_ can return `cursor' from the function.
static struct page *objidx_to_page_and_offset(struct page *first_page,
unsigned long obj_offset,
unsigned long *offset_in_page);
this can save ~20 instructions, which is not so terrible for a hot path
like obj_malloc(). what do you think?
well, seems that `unsigned long *offset_in_page' can be calculated
outside of this function too, it's basically
*offset_in_page = (obj_idx * class->size) & ~PAGE_MASK;
so we don't need to supply it to this function, nor modify it there.
which can save ~40 instructions on my system. does this sound silly?
-ss
> + cursor = first_page;
> + nr_page = offset >> PAGE_SHIFT;
>
> - obj = page_to_pfn(page) << OBJ_INDEX_BITS;
> - obj |= ((obj_idx) & OBJ_INDEX_MASK);
> - obj <<= OBJ_TAG_BITS;
> + *offset_in_page = offset & ~PAGE_MASK;
> +
> + for (i = 0; i < nr_page; i++)
> + cursor = get_next_page(cursor);
>
> - return (void *)obj;
> + *obj_page = cursor;
> }
-ss
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next prev parent reply other threads:[~2016-04-17 14:58 UTC|newest]
Thread overview: 185+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-30 7:11 [PATCH v3 00/16] Support non-lru page migration Minchan Kim
2016-03-30 7:11 ` Minchan Kim
2016-03-30 7:12 ` [PATCH v3 01/16] mm: use put_page to free page instead of putback_lru_page Minchan Kim
2016-03-30 7:12 ` Minchan Kim
2016-03-30 7:12 ` Minchan Kim
2016-04-01 12:58 ` Vlastimil Babka
2016-04-01 12:58 ` Vlastimil Babka
2016-04-01 12:58 ` Vlastimil Babka
2016-04-04 1:39 ` Minchan Kim
2016-04-04 1:39 ` Minchan Kim
2016-04-04 1:39 ` Minchan Kim
2016-04-04 4:45 ` Naoya Horiguchi
2016-04-04 4:45 ` Naoya Horiguchi
2016-04-04 14:46 ` Vlastimil Babka
2016-04-04 14:46 ` Vlastimil Babka
2016-04-04 14:46 ` Vlastimil Babka
2016-04-05 1:54 ` Naoya Horiguchi
2016-04-05 1:54 ` Naoya Horiguchi
2016-04-05 1:54 ` Naoya Horiguchi
2016-04-05 8:20 ` Vlastimil Babka
2016-04-05 8:20 ` Vlastimil Babka
2016-04-05 8:20 ` Vlastimil Babka
2016-04-06 0:54 ` Naoya Horiguchi
2016-04-06 0:54 ` Naoya Horiguchi
2016-04-06 0:54 ` Naoya Horiguchi
2016-04-06 7:57 ` Vlastimil Babka
2016-04-06 7:57 ` Vlastimil Babka
2016-04-06 7:57 ` Vlastimil Babka
2016-04-04 4:45 ` Naoya Horiguchi
2016-04-04 5:53 ` Balbir Singh
2016-04-04 5:53 ` Balbir Singh
2016-04-04 5:53 ` Balbir Singh
2016-04-04 6:01 ` Minchan Kim
2016-04-04 6:01 ` Minchan Kim
2016-04-04 6:01 ` Minchan Kim
2016-04-05 3:10 ` Balbir Singh
2016-04-05 3:10 ` Balbir Singh
2016-04-05 3:10 ` Balbir Singh
2016-03-30 7:12 ` [PATCH v3 02/16] mm/compaction: support non-lru movable page migration Minchan Kim
2016-03-30 7:12 ` Minchan Kim
2016-03-30 7:12 ` Minchan Kim
2016-03-30 7:12 ` Minchan Kim
2016-04-01 21:29 ` Vlastimil Babka
2016-04-01 21:29 ` Vlastimil Babka
2016-04-04 5:12 ` Minchan Kim
2016-04-04 5:12 ` Minchan Kim
2016-04-04 13:24 ` Vlastimil Babka
2016-04-04 13:24 ` Vlastimil Babka
2016-04-04 13:24 ` Vlastimil Babka
2016-04-07 2:35 ` Minchan Kim
2016-04-07 2:35 ` Minchan Kim
2016-04-07 2:35 ` Minchan Kim
2016-04-04 13:24 ` Vlastimil Babka
2016-04-04 5:12 ` Minchan Kim
2016-04-01 21:29 ` Vlastimil Babka
2016-04-12 8:00 ` Chulmin Kim
2016-04-12 8:00 ` Chulmin Kim
2016-04-12 14:25 ` Minchan Kim
2016-04-12 14:25 ` Minchan Kim
2016-03-30 7:12 ` [PATCH v3 03/16] mm: add non-lru movable page support document Minchan Kim
2016-03-30 7:12 ` Minchan Kim
2016-04-01 14:38 ` Vlastimil Babka
2016-04-01 14:38 ` Vlastimil Babka
2016-04-01 14:38 ` Vlastimil Babka
2016-04-04 2:25 ` Minchan Kim
2016-04-04 2:25 ` Minchan Kim
2016-04-04 2:25 ` Minchan Kim
2016-04-04 13:09 ` Vlastimil Babka
2016-04-04 13:09 ` Vlastimil Babka
2016-04-04 13:09 ` Vlastimil Babka
2016-04-07 2:27 ` Minchan Kim
2016-04-07 2:27 ` Minchan Kim
2016-04-07 2:27 ` Minchan Kim
2016-03-30 7:12 ` Minchan Kim
2016-03-30 7:12 ` [PATCH v3 04/16] mm/balloon: use general movable page feature into balloon Minchan Kim
2016-03-30 7:12 ` Minchan Kim
2016-04-05 12:03 ` Vlastimil Babka
2016-04-05 12:03 ` Vlastimil Babka
2016-04-05 12:03 ` Vlastimil Babka
2016-04-11 4:29 ` Minchan Kim
2016-04-11 4:29 ` Minchan Kim
2016-04-11 4:29 ` Minchan Kim
2016-03-30 7:12 ` Minchan Kim
2016-03-30 7:12 ` [PATCH v3 05/16] zsmalloc: keep max_object in size_class Minchan Kim
2016-03-30 7:12 ` Minchan Kim
2016-04-17 15:08 ` Sergey Senozhatsky
2016-04-17 15:08 ` Sergey Senozhatsky
2016-04-17 15:08 ` Sergey Senozhatsky
2016-03-30 7:12 ` Minchan Kim
2016-03-30 7:12 ` [PATCH v3 06/16] zsmalloc: squeeze inuse into page->mapping Minchan Kim
2016-03-30 7:12 ` Minchan Kim
2016-04-17 15:08 ` Sergey Senozhatsky
2016-04-17 15:08 ` Sergey Senozhatsky
2016-04-17 15:08 ` Sergey Senozhatsky
2016-04-19 7:40 ` Minchan Kim
2016-04-19 7:40 ` Minchan Kim
2016-04-19 7:40 ` Minchan Kim
2016-03-30 7:12 ` Minchan Kim
2016-03-30 7:12 ` [PATCH v3 07/16] zsmalloc: remove page_mapcount_reset Minchan Kim
2016-03-30 7:12 ` Minchan Kim
2016-04-17 15:11 ` Sergey Senozhatsky
2016-04-17 15:11 ` Sergey Senozhatsky
2016-04-17 15:11 ` Sergey Senozhatsky
2016-03-30 7:12 ` Minchan Kim
2016-03-30 7:12 ` [PATCH v3 08/16] zsmalloc: squeeze freelist into page->mapping Minchan Kim
2016-03-30 7:12 ` Minchan Kim
2016-03-30 7:12 ` Minchan Kim
2016-04-17 15:56 ` Sergey Senozhatsky
2016-04-17 15:56 ` Sergey Senozhatsky [this message]
2016-04-17 15:56 ` Sergey Senozhatsky
2016-04-19 7:42 ` Minchan Kim
2016-04-19 7:42 ` Minchan Kim
2016-04-19 7:42 ` Minchan Kim
2016-03-30 7:12 ` [PATCH v3 09/16] zsmalloc: move struct zs_meta from mapping to freelist Minchan Kim
2016-03-30 7:12 ` Minchan Kim
2016-03-30 7:12 ` Minchan Kim
2016-04-17 15:22 ` Sergey Senozhatsky
2016-04-17 15:22 ` Sergey Senozhatsky
2016-04-17 15:22 ` Sergey Senozhatsky
2016-03-30 7:12 ` [PATCH v3 10/16] zsmalloc: factor page chain functionality out Minchan Kim
2016-03-30 7:12 ` Minchan Kim
2016-03-30 7:12 ` Minchan Kim
2016-04-18 0:33 ` Sergey Senozhatsky
2016-04-18 0:33 ` Sergey Senozhatsky
2016-04-19 7:46 ` Minchan Kim
2016-04-19 7:46 ` Minchan Kim
2016-04-19 7:46 ` Minchan Kim
2016-04-18 0:33 ` Sergey Senozhatsky
2016-03-30 7:12 ` [PATCH v3 11/16] zsmalloc: separate free_zspage from putback_zspage Minchan Kim
2016-03-30 7:12 ` Minchan Kim
2016-03-30 7:12 ` Minchan Kim
2016-04-18 1:04 ` Sergey Senozhatsky
2016-04-18 1:04 ` Sergey Senozhatsky
2016-04-19 7:51 ` Minchan Kim
2016-04-19 7:51 ` Minchan Kim
2016-04-19 7:53 ` Sergey Senozhatsky
2016-04-19 7:53 ` Sergey Senozhatsky
2016-04-19 7:53 ` Sergey Senozhatsky
2016-04-19 7:51 ` Minchan Kim
2016-04-18 1:04 ` Sergey Senozhatsky
2016-03-30 7:12 ` [PATCH v3 12/16] zsmalloc: zs_compact refactoring Minchan Kim
2016-03-30 7:12 ` Minchan Kim
2016-03-30 7:12 ` Minchan Kim
2016-04-04 8:04 ` Chulmin Kim
2016-04-04 8:04 ` Chulmin Kim
2016-04-04 9:01 ` Minchan Kim
2016-04-04 9:01 ` Minchan Kim
2016-03-30 7:12 ` [PATCH v3 13/16] zsmalloc: migrate head page of zspage Minchan Kim
2016-03-30 7:12 ` Minchan Kim
2016-03-30 7:12 ` Minchan Kim
2016-04-06 13:01 ` Chulmin Kim
2016-04-06 13:01 ` Chulmin Kim
2016-04-07 0:34 ` Chulmin Kim
2016-04-07 0:34 ` Chulmin Kim
2016-04-07 0:43 ` Minchan Kim
2016-04-07 0:43 ` Minchan Kim
2016-04-19 6:08 ` Chulmin Kim
2016-04-19 6:08 ` Chulmin Kim
2016-04-19 6:15 ` Minchan Kim
2016-04-19 6:15 ` Minchan Kim
2016-03-30 7:12 ` [PATCH v3 14/16] zsmalloc: use single linked list for page chain Minchan Kim
2016-03-30 7:12 ` Minchan Kim
2016-03-30 7:12 ` Minchan Kim
2016-03-30 7:12 ` [PATCH v3 15/16] zsmalloc: migrate tail pages in zspage Minchan Kim
2016-03-30 7:12 ` Minchan Kim
2016-03-30 7:12 ` Minchan Kim
2016-03-30 7:12 ` [PATCH v3 16/16] zram: use __GFP_MOVABLE for memory allocation Minchan Kim
2016-03-30 7:12 ` Minchan Kim
2016-03-30 7:12 ` Minchan Kim
2016-03-30 23:11 ` [PATCH v3 00/16] Support non-lru page migration Andrew Morton
2016-03-30 23:11 ` Andrew Morton
2016-03-30 23:11 ` Andrew Morton
2016-03-31 0:29 ` Sergey Senozhatsky
2016-03-31 0:29 ` Sergey Senozhatsky
2016-03-31 0:29 ` Sergey Senozhatsky
2016-03-31 0:57 ` Minchan Kim
2016-03-31 0:57 ` Minchan Kim
2016-03-31 0:57 ` Minchan Kim
2016-03-31 0:57 ` Minchan Kim
2016-03-31 0:57 ` Minchan Kim
2016-03-31 0:57 ` Minchan Kim
2016-04-04 13:17 ` John Einar Reitan
2016-04-04 13:17 ` John Einar Reitan
2016-04-11 4:35 ` Minchan Kim
2016-04-11 4:35 ` Minchan Kim
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