diff for duplicates of <20170913121433.yjzloaf6g447zeq2@dhcp22.suse.cz>
diff --git a/a/1.txt b/N1/1.txt
index 8d8b255..f1016f7 100644
--- a/a/1.txt
+++ b/N1/1.txt
@@ -24,54 +24,4 @@ On Wed 13-09-17 14:10:01, Michal Hocko wrote:
>
> So what do you think about the following wording:
-Ups, wrong patch
-
-
->From 8639496a834b4a7c24972ec23b17e50f0d6a304c Mon Sep 17 00:00:00 2001
-From: Michal Hocko <mhocko@suse.com>
-Date: Mon, 14 Aug 2017 10:46:12 +0200
-Subject: [PATCH 1/2] mm, memory_hotplug: do not fail offlining too early
-
-Memory offlining can fail just too eagerly under a heavy memory pressure.
-
-[ 5410.336792] page:ffffea22a646bd00 count:255 mapcount:252 mapping:ffff88ff926c9f38 index:0x3
-[ 5410.336809] flags: 0x9855fe40010048(uptodate|active|mappedtodisk)
-[ 5410.336811] page dumped because: isolation failed
-[ 5410.336813] page->mem_cgroup:ffff8801cd662000
-[ 5420.655030] memory offlining [mem 0x18b580000000-0x18b5ffffffff] failed
-
-Isolation has failed here because the page is not on LRU. Most probably
-because it was on the pcp LRU cache or it has been removed from the LRU
-already but it hasn't been freed yet. In both cases the page doesn't look
-non-migrable so retrying more makes sense.
-
-__offline_pages seems rather cluttered when it comes to the retry
-logic. We have 5 retries at maximum and a timeout. We could argue
-whether the timeout makes sense but failing just because of a race when
-somebody isoltes a page from LRU or puts it on a pcp LRU lists is just
-wrong. It only takes it to race with a process which unmaps some pages
-and remove them from the LRU list and we can fail the whole offline
-because of something that is a temporary condition and actually not
-harmful for the offline.
-
-Please note that unmovable pages should be already excluded during
-start_isolate_page_range. We could argue that has_unmovable_pages is
-racy and MIGRATE_MOVABLE check doesn't provide any hard guarantee either
-but kernel zones (aka < ZONE_MOVABLE) will very likely detect unmovable
-pages in most cases and movable zone shouldn't contain unmovable pages
-at all. Some of those pages might be pinned but not for ever because
-that would be a bug on its own. In any case the context is still
-interruptible and so the userspace can easily bail out when the
-operation takes too long. This is certainly better behavior than a
-hardcoded retry loop which is racy.
-
-Fix this by removing the max retry count and only rely on the timeout
-resp. interruption by a signal from the userspace. Also retry rather
-than fail when check_pages_isolated sees some !free pages because those
-could be a result of the race as well.
-
-Signed-off-by: Michal Hocko <mhocko@suse.com>
-
---
-Michal Hocko
-SUSE Labs
\ No newline at end of file
+Ups, wrong patch
\ No newline at end of file
diff --git a/a/content_digest b/N1/content_digest
index 0bb2b6b..42d4f14 100644
--- a/a/content_digest
+++ b/N1/content_digest
@@ -72,57 +72,7 @@
"> \n",
"> So what do you think about the following wording:\n",
"\n",
- "Ups, wrong patch\n",
- "\n",
- "\n",
- ">From 8639496a834b4a7c24972ec23b17e50f0d6a304c Mon Sep 17 00:00:00 2001\n",
- "From: Michal Hocko <mhocko\@suse.com>\n",
- "Date: Mon, 14 Aug 2017 10:46:12 +0200\n",
- "Subject: [PATCH 1/2] mm, memory_hotplug: do not fail offlining too early\n",
- "\n",
- "Memory offlining can fail just too eagerly under a heavy memory pressure.\n",
- "\n",
- "[ 5410.336792] page:ffffea22a646bd00 count:255 mapcount:252 mapping:ffff88ff926c9f38 index:0x3\n",
- "[ 5410.336809] flags: 0x9855fe40010048(uptodate|active|mappedtodisk)\n",
- "[ 5410.336811] page dumped because: isolation failed\n",
- "[ 5410.336813] page->mem_cgroup:ffff8801cd662000\n",
- "[ 5420.655030] memory offlining [mem 0x18b580000000-0x18b5ffffffff] failed\n",
- "\n",
- "Isolation has failed here because the page is not on LRU. Most probably\n",
- "because it was on the pcp LRU cache or it has been removed from the LRU\n",
- "already but it hasn't been freed yet. In both cases the page doesn't look\n",
- "non-migrable so retrying more makes sense.\n",
- "\n",
- "__offline_pages seems rather cluttered when it comes to the retry\n",
- "logic. We have 5 retries at maximum and a timeout. We could argue\n",
- "whether the timeout makes sense but failing just because of a race when\n",
- "somebody isoltes a page from LRU or puts it on a pcp LRU lists is just\n",
- "wrong. It only takes it to race with a process which unmaps some pages\n",
- "and remove them from the LRU list and we can fail the whole offline\n",
- "because of something that is a temporary condition and actually not\n",
- "harmful for the offline.\n",
- "\n",
- "Please note that unmovable pages should be already excluded during\n",
- "start_isolate_page_range. We could argue that has_unmovable_pages is\n",
- "racy and MIGRATE_MOVABLE check doesn't provide any hard guarantee either\n",
- "but kernel zones (aka < ZONE_MOVABLE) will very likely detect unmovable\n",
- "pages in most cases and movable zone shouldn't contain unmovable pages\n",
- "at all. Some of those pages might be pinned but not for ever because\n",
- "that would be a bug on its own. In any case the context is still\n",
- "interruptible and so the userspace can easily bail out when the\n",
- "operation takes too long. This is certainly better behavior than a\n",
- "hardcoded retry loop which is racy.\n",
- "\n",
- "Fix this by removing the max retry count and only rely on the timeout\n",
- "resp. interruption by a signal from the userspace. Also retry rather\n",
- "than fail when check_pages_isolated sees some !free pages because those\n",
- "could be a result of the race as well.\n",
- "\n",
- "Signed-off-by: Michal Hocko <mhocko\@suse.com>\n",
- "\n",
- "-- \n",
- "Michal Hocko\n",
- "SUSE Labs"
+ "Ups, wrong patch"
]
-d8d430233718411dd1b0aefab0a21ba3eb3267917c0b7cb5a3526d5e26ee2dac
+644244094b1e2833e6c10526043bda6a6418816b66ca27259b58f864ee0cf0a7
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