From: "Huang\, Ying" <ying.huang@intel.com>
To: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Michal Hocko <mhocko@suse.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Shaohua Li <shli@kernel.org>, Hugh Dickins <hughd@google.com>,
Minchan Kim <minchan@kernel.org>, Rik van Riel <riel@redhat.com>,
Daniel Jordan <daniel.m.jordan@oracle.com>,
Dan Williams <dan.j.williams@intel.com>
Subject: Re: [PATCH v2 7/7] swap, put_swap_page: Share more between huge/normal code path
Date: Wed, 18 Jul 2018 10:56:32 +0800 [thread overview]
Message-ID: <87k1ptgskf.fsf@yhuang-dev.intel.com> (raw)
In-Reply-To: <98288fec-1199-1b25-8c8c-18d60c33e596@linux.intel.com> (Dave Hansen's message of "Tue, 17 Jul 2018 11:36:54 -0700")
Dave Hansen <dave.hansen@linux.intel.com> writes:
> On 07/16/2018 05:55 PM, Huang, Ying wrote:
>> text data bss dec hex filename
>> base: 24215 2028 340 26583 67d7 mm/swapfile.o
>> unified: 24577 2028 340 26945 6941 mm/swapfile.o
>
> That's a bit more than I'd expect looking at the rest of the diff. Make
> me wonder if we missed an #ifdef somewhere or the compiler is getting
> otherwise confused.
>
> Might be worth a 10-minute look at the disassembly.
Dig one step deeper via 'size -A mm/swapfile.o' and diff between base
and unified,
--- b.s 2018-07-18 09:42:07.872501680 +0800
+++ h.s 2018-07-18 09:50:37.984499168 +0800
@@ -1,6 +1,6 @@
mm/swapfile.o :
section size addr
-.text 17815 0
+.text 17927 0
.data 1288 0
.bss 340 0
___ksymtab_gpl+nr_swap_pages 8 0
@@ -26,8 +26,8 @@
.data.once 1 0
.comment 35 0
.note.GNU-stack 0 0
-.orc_unwind_ip 1380 0
-.orc_unwind 2070 0
-Total 26810
+.orc_unwind_ip 1480 0
+.orc_unwind 2220 0
+Total 27172
The total difference is same: 27172 - 26810 = 362 = 24577 - 24215.
The text section difference is small: 17927 - 17815 = 112. The
additional size change comes from unwinder information: (1480 + 2220) -
(1380 + 2070) = 250. If the frame pointer unwinder is chosen, this cost
nothing, but if the ORC unwinder is chosen, this is the real difference.
For 112 text section difference, use 'objdump -t' to get symbol size and
compare,
--- b.od 2018-07-18 10:45:05.768483075 +0800
+++ h.od 2018-07-18 10:44:39.556483204 +0800
@@ -30,9 +30,9 @@
00000000000000a3 cluster_list_add_tail
000000000000001e __kunmap_atomic.isra.34
000000000000018c swap_count_continued
-00000000000000ac __swap_entry_free
000000000000000f put_swap_device.isra.35
00000000000000b4 inc_cluster_info_page
+000000000000006f __swap_entry_free_locked
000000000000004a _enable_swap_info
0000000000000046 wait_on_page_writeback
000000000000002e inode_to_bdi
@@ -53,8 +53,8 @@
0000000000000012 __x64_sys_swapon
0000000000000011 __ia32_sys_swapon
000000000000007a get_swap_device
-0000000000000032 swap_free
-0000000000000035 put_swap_page
+000000000000006e swap_free
+0000000000000078 put_swap_page
0000000000000267 swapcache_free_entries
0000000000000058 page_swapcount
000000000000003a __swap_count
@@ -64,7 +64,7 @@
000000000000011a try_to_free_swap
00000000000001fb get_swap_pages
0000000000000098 get_swap_page_of_type
-00000000000001b8 free_swap_and_cache
+00000000000001e6 free_swap_and_cache
0000000000000543 try_to_unuse
000000000000000e __x64_sys_swapoff
000000000000000d __ia32_sys_swapoff
The size of put_swap_page() change is small: 0x78 - 0x35 = 67. But
__swap_entry_free() is inlined by compiler, which cause some code
dilating.
Best Regards,
Huang, Ying
next prev parent reply other threads:[~2018-07-18 2:56 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-17 0:55 [PATCH v2 0/7] swap: THP optimizing refactoring Huang, Ying
2018-07-17 0:55 ` [PATCH v2 1/7] swap: Add comments to lock_cluster_or_swap_info() Huang, Ying
2018-07-17 18:27 ` Dave Hansen
2018-07-18 3:09 ` Huang, Ying
2018-07-17 0:55 ` [PATCH v2 2/7] mm/swapfile.c: Replace some #ifdef with IS_ENABLED() Huang, Ying
2018-07-17 18:32 ` Dave Hansen
2018-07-18 3:25 ` Huang, Ying
2018-07-18 15:15 ` Dave Hansen
2018-07-19 4:42 ` Huang, Ying
2018-07-17 0:55 ` [PATCH v2 3/7] swap: Use swap_count() in swap_page_trans_huge_swapped() Huang, Ying
2018-07-17 0:55 ` [PATCH v2 4/7] swap: Unify normal/huge code path " Huang, Ying
2018-07-17 0:55 ` [PATCH v2 5/7] swap: Unify normal/huge code path in put_swap_page() Huang, Ying
2018-07-17 0:55 ` [PATCH v2 6/7] swap: Add __swap_entry_free_locked() Huang, Ying
2018-07-17 0:55 ` [PATCH v2 7/7] swap, put_swap_page: Share more between huge/normal code path Huang, Ying
2018-07-17 18:36 ` Dave Hansen
2018-07-18 2:56 ` Huang, Ying [this message]
2018-07-18 15:13 ` Dave Hansen
2018-07-17 15:17 ` [PATCH v2 0/7] swap: THP optimizing refactoring Daniel Jordan
2018-07-18 2:56 ` Huang, Ying
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87k1ptgskf.fsf@yhuang-dev.intel.com \
--to=ying.huang@intel.com \
--cc=akpm@linux-foundation.org \
--cc=dan.j.williams@intel.com \
--cc=daniel.m.jordan@oracle.com \
--cc=dave.hansen@linux.intel.com \
--cc=hannes@cmpxchg.org \
--cc=hughd@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@suse.com \
--cc=minchan@kernel.org \
--cc=riel@redhat.com \
--cc=shli@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).