From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, dan.j.williams@intel.com,
daniel.m.jordan@oracle.com, david@redhat.com, jmorris@namei.org,
ktkhai@virtuozzo.com, linux-mm@kvack.org, mhocko@suse.com,
mm-commits@vger.kernel.org, pankaj.gupta.linux@gmail.com,
pasha.tatashin@soleen.com, sashal@kernel.org,
shile.zhang@linux.alibaba.com, stable@vger.kernel.org,
torvalds@linux-foundation.org, vbabka@suse.cz, yiwei@redhat.com
Subject: [patch 051/131] mm: call cond_resched() from deferred_init_memmap()
Date: Wed, 03 Jun 2020 15:59:27 -0700 [thread overview]
Message-ID: <20200603225927.oWsDfB6-g%akpm@linux-foundation.org> (raw)
In-Reply-To: <20200603155549.e041363450869eaae4c7f05b@linux-foundation.org>
From: Pavel Tatashin <pasha.tatashin@soleen.com>
Subject: mm: call cond_resched() from deferred_init_memmap()
Now that deferred pages are initialized with interrupts enabled we can
replace touch_nmi_watchdog() with cond_resched(), as it was before
3a2d7fa8a3d5.
For now, we cannot do the same in deferred_grow_zone() as it is still
initializes pages with interrupts disabled.
This change fixes RCU problem described in
https://lkml.kernel.org/r/20200401104156.11564-2-david@redhat.com
[ 60.474005] rcu: INFO: rcu_sched detected stalls on CPUs/tasks:
[ 60.475000] rcu: 1-...0: (0 ticks this GP) idle=02a/1/0x4000000000000000 softirq=1/1 fqs=15000
[ 60.475000] rcu: (detected by 0, t=60002 jiffies, g=-1199, q=1)
[ 60.475000] Sending NMI from CPU 0 to CPUs 1:
[ 1.760091] NMI backtrace for cpu 1
[ 1.760091] CPU: 1 PID: 20 Comm: pgdatinit0 Not tainted 4.18.0-147.9.1.el8_1.x86_64 #1
[ 1.760091] Hardware name: Red Hat KVM, BIOS 1.13.0-1.module+el8.2.0+5520+4e5817f3 04/01/2014
[ 1.760091] RIP: 0010:__init_single_page.isra.65+0x10/0x4f
[ 1.760091] Code: 48 83 cf 63 48 89 f8 0f 1f 40 00 48 89 c6 48 89 d7 e8 6b 18 80 ff 66 90 5b c3 31 c0 b9 10 00 00 00 49 89 f8 48 c1 e6 33 f3 ab <b8> 07 00 00 00 48 c1 e2 36 41 c7 40 34 01 00 00 00 48 c1 e0 33 41
[ 1.760091] RSP: 0000:ffffba783123be40 EFLAGS: 00000006
[ 1.760091] RAX: 0000000000000000 RBX: fffffad34405e300 RCX: 0000000000000000
[ 1.760091] RDX: 0000000000000000 RSI: 0010000000000000 RDI: fffffad34405e340
[ 1.760091] RBP: 0000000033f3177e R08: fffffad34405e300 R09: 0000000000000002
[ 1.760091] R10: 000000000000002b R11: ffff98afb691a500 R12: 0000000000000002
[ 1.760091] R13: 0000000000000000 R14: 000000003f03ea00 R15: 000000003e10178c
[ 1.760091] FS: 0000000000000000(0000) GS:ffff9c9ebeb00000(0000) knlGS:0000000000000000
[ 1.760091] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1.760091] CR2: 00000000ffffffff CR3: 000000a1cf20a001 CR4: 00000000003606e0
[ 1.760091] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1.760091] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 1.760091] Call Trace:
[ 1.760091] deferred_init_pages+0x8f/0xbf
[ 1.760091] deferred_init_memmap+0x184/0x29d
[ 1.760091] ? deferred_free_pages.isra.97+0xba/0xba
[ 1.760091] kthread+0x112/0x130
[ 1.760091] ? kthread_flush_work_fn+0x10/0x10
[ 1.760091] ret_from_fork+0x35/0x40
[ 89.123011] node 0 initialised, 1055935372 pages in 88650ms
Link: http://lkml.kernel.org/r/20200403140952.17177-4-pasha.tatashin@soleen.com
Fixes: 3a2d7fa8a3d5 ("mm: disable interrupts while initializing deferred pages")
Reported-by: Yiqian Wei <yiwei@redhat.com>
Tested-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: James Morris <jmorris@namei.org>
Cc: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Shile Zhang <shile.zhang@linux.alibaba.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org> [4.17+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/page_alloc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/page_alloc.c~mm-call-cond_resched-from-deferred_init_memmap
+++ a/mm/page_alloc.c
@@ -1870,7 +1870,7 @@ static int __init deferred_init_memmap(v
*/
while (spfn < epfn) {
nr_pages += deferred_init_maxorder(&i, zone, &spfn, &epfn);
- touch_nmi_watchdog();
+ cond_resched();
}
zone_empty:
/* Sanity check that the next zone really is unpopulated */
_
next prev parent reply other threads:[~2020-06-03 22:59 UTC|newest]
Thread overview: 142+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-03 22:55 incoming Andrew Morton
2020-06-03 22:56 ` [patch 001/131] mm/slub: fix a memory leak in sysfs_slab_add() Andrew Morton
2020-06-03 22:56 ` [patch 002/131] mm/memcg: optimize memory.numa_stat like memory.stat Andrew Morton
2020-06-03 22:56 ` [patch 003/131] mm/gup: move __get_user_pages_fast() down a few lines in gup.c Andrew Morton
2020-06-04 1:51 ` John Hubbard
2020-06-03 22:56 ` [patch 004/131] mm/gup: refactor and de-duplicate gup_fast() code Andrew Morton
2020-06-04 2:19 ` Linus Torvalds
2020-06-04 3:19 ` Linus Torvalds
2020-06-04 4:31 ` Linus Torvalds
2020-06-04 5:18 ` John Hubbard
2020-06-03 22:56 ` [patch 005/131] mm/gup: introduce pin_user_pages_fast_only() Andrew Morton
2020-06-03 22:56 ` [patch 006/131] drm/i915: convert get_user_pages() --> pin_user_pages() Andrew Morton
2020-06-03 22:56 ` [patch 007/131] mm/gup: might_lock_read(mmap_sem) in get_user_pages_fast() Andrew Morton
2020-06-03 22:56 ` [patch 008/131] kasan: stop tests being eliminated as dead code with FORTIFY_SOURCE Andrew Morton
2020-06-03 22:56 ` [patch 009/131] string.h: fix incompatibility between FORTIFY_SOURCE and KASAN Andrew Morton
2020-06-03 22:56 ` [patch 010/131] mm: clarify __GFP_MEMALLOC usage Andrew Morton
2020-06-03 22:56 ` [patch 011/131] mm: memblock: replace dereferences of memblock_region.nid with API calls Andrew Morton
2020-06-03 22:56 ` [patch 012/131] mm: make early_pfn_to_nid() and related defintions close to each other Andrew Morton
2020-06-03 22:57 ` [patch 013/131] mm: remove CONFIG_HAVE_MEMBLOCK_NODE_MAP option Andrew Morton
2020-06-03 22:57 ` [patch 014/131] mm: free_area_init: use maximal zone PFNs rather than zone sizes Andrew Morton
2020-06-03 22:57 ` [patch 015/131] mm: use free_area_init() instead of free_area_init_nodes() Andrew Morton
2020-06-03 22:57 ` [patch 016/131] alpha: simplify detection of memory zone boundaries Andrew Morton
2020-06-03 22:57 ` [patch 017/131] arm: " Andrew Morton
2020-06-03 22:57 ` [patch 018/131] arm64: simplify detection of memory zone boundaries for UMA configs Andrew Morton
2020-06-03 22:57 ` [patch 019/131] csky: simplify detection of memory zone boundaries Andrew Morton
2020-06-03 22:57 ` [patch 020/131] m68k: mm: " Andrew Morton
2020-06-03 22:57 ` [patch 021/131] parisc: " Andrew Morton
2020-06-03 22:57 ` [patch 022/131] sparc32: " Andrew Morton
2020-06-03 22:57 ` [patch 023/131] unicore32: " Andrew Morton
2020-06-03 22:57 ` [patch 024/131] xtensa: " Andrew Morton
2020-06-03 22:57 ` [patch 025/131] mm: memmap_init: iterate over memblock regions rather that check each PFN Andrew Morton
2020-06-03 22:57 ` [patch 026/131] mm: remove early_pfn_in_nid() and CONFIG_NODES_SPAN_OTHER_NODES Andrew Morton
2020-06-03 22:58 ` [patch 027/131] mm: free_area_init: allow defining max_zone_pfn in descending order Andrew Morton
2020-06-03 22:58 ` [patch 028/131] mm: rename free_area_init_node() to free_area_init_memoryless_node() Andrew Morton
2020-06-03 22:58 ` [patch 029/131] mm: clean up free_area_init_node() and its helpers Andrew Morton
2020-06-03 22:58 ` [patch 030/131] mm: simplify find_min_pfn_with_active_regions() Andrew Morton
2020-06-03 22:58 ` [patch 031/131] docs/vm: update memory-models documentation Andrew Morton
2020-06-03 22:58 ` [patch 032/131] mm/page_alloc.c: bad_[reason|flags] is not necessary when PageHWPoison Andrew Morton
2020-06-03 22:58 ` [patch 033/131] mm/page_alloc.c: bad_flags is not necessary for bad_page() Andrew Morton
2020-06-03 22:58 ` [patch 034/131] mm/page_alloc.c: rename free_pages_check_bad() to check_free_page_bad() Andrew Morton
2020-06-03 22:58 ` [patch 035/131] mm/page_alloc.c: rename free_pages_check() to check_free_page() Andrew Morton
2020-06-03 22:58 ` [patch 036/131] mm/page_alloc.c: extract check_[new|free]_page_bad() common part to page_bad_reason() Andrew Morton
2020-06-03 22:58 ` [patch 037/131] mm,page_alloc,cma: conditionally prefer cma pageblocks for movable allocations Andrew Morton
2020-06-03 22:58 ` [patch 038/131] mm/page_alloc.c: remove unused free_bootmem_with_active_regions Andrew Morton
2020-06-03 22:58 ` [patch 039/131] mm/page_alloc.c: only tune sysctl_lowmem_reserve_ratio value once when changing it Andrew Morton
2020-06-03 22:58 ` [patch 040/131] mm/page_alloc.c: clear out zone->lowmem_reserve[] if the zone is empty Andrew Morton
2020-06-03 22:58 ` [patch 041/131] mm/vmstat.c: do not show lowmem reserve protection information of empty zone Andrew Morton
2020-06-03 22:58 ` [patch 042/131] mm/page_alloc: use ac->high_zoneidx for classzone_idx Andrew Morton
2020-06-03 22:59 ` [patch 043/131] mm/page_alloc: integrate classzone_idx and high_zoneidx Andrew Morton
2020-06-03 22:59 ` [patch 044/131] mm/page_alloc.c: use NODE_MASK_NONE in build_zonelists() Andrew Morton
2020-06-03 22:59 ` [patch 045/131] mm: rename gfpflags_to_migratetype to gfp_migratetype for same convention Andrew Morton
2020-06-03 22:59 ` [patch 046/131] mm/page_alloc.c: reset numa stats for boot pagesets Andrew Morton
2020-06-03 22:59 ` [patch 047/131] mm, page_alloc: reset the zone->watermark_boost early Andrew Morton
2020-06-03 22:59 ` [patch 048/131] mm/page_alloc: restrict and formalize compound_page_dtors[] Andrew Morton
2020-06-03 22:59 ` [patch 049/131] mm/pagealloc.c: call touch_nmi_watchdog() on max order boundaries in deferred init Andrew Morton
2020-06-03 22:59 ` [patch 050/131] mm: initialize deferred pages with interrupts enabled Andrew Morton
2020-06-03 22:59 ` Andrew Morton [this message]
2020-06-03 22:59 ` [patch 052/131] padata: remove exit routine Andrew Morton
2020-06-03 22:59 ` [patch 053/131] padata: initialize earlier Andrew Morton
2020-06-03 22:59 ` [patch 054/131] padata: allocate work structures for parallel jobs from a pool Andrew Morton
2020-06-03 22:59 ` [patch 055/131] padata: add basic support for multithreaded jobs Andrew Morton
2020-06-03 22:59 ` [patch 056/131] mm: don't track number of pages during deferred initialization Andrew Morton
2020-06-03 22:59 ` [patch 057/131] mm: parallelize deferred_init_memmap() Andrew Morton
2020-06-03 22:59 ` [patch 058/131] mm: make deferred init's max threads arch-specific Andrew Morton
2020-06-03 22:59 ` [patch 059/131] padata: document multithreaded jobs Andrew Morton
2020-06-03 23:00 ` [patch 060/131] mm/page_alloc.c: add missing newline Andrew Morton
2020-06-03 23:00 ` [patch 061/131] khugepaged: add self test Andrew Morton
2020-06-03 23:00 ` [patch 062/131] khugepaged: do not stop collapse if less than half PTEs are referenced Andrew Morton
2020-06-03 23:00 ` [patch 063/131] khugepaged: drain all LRU caches before scanning pages Andrew Morton
2020-06-03 23:00 ` [patch 064/131] khugepaged: drain LRU add pagevec after swapin Andrew Morton
2020-06-03 23:00 ` [patch 065/131] khugepaged: allow to collapse a page shared across fork Andrew Morton
2020-06-03 23:00 ` [patch 066/131] khugepaged: allow to collapse PTE-mapped compound pages Andrew Morton
2020-06-03 23:00 ` [patch 067/131] thp: change CoW semantics for anon-THP Andrew Morton
2020-06-03 23:00 ` [patch 068/131] khugepaged: introduce 'max_ptes_shared' tunable Andrew Morton
2020-06-03 23:00 ` [patch 069/131] hugetlbfs: add arch_hugetlb_valid_size Andrew Morton
2020-06-03 23:00 ` [patch 070/131] hugetlbfs: move hugepagesz= parsing to arch independent code Andrew Morton
2020-06-03 23:00 ` [patch 071/131] hugetlbfs: remove hugetlb_add_hstate() warning for existing hstate Andrew Morton
2020-06-03 23:00 ` [patch 072/131] hugetlbfs: clean up command line processing Andrew Morton
2020-06-03 23:00 ` [patch 073/131] hugetlbfs: fix changes to " Andrew Morton
2020-06-03 23:00 ` [patch 074/131] mm/hugetlb: avoid unnecessary check on pud and pmd entry in huge_pte_offset Andrew Morton
2020-06-03 23:00 ` [patch 075/131] arm64/mm: drop __HAVE_ARCH_HUGE_PTEP_GET Andrew Morton
2020-06-03 23:01 ` [patch 076/131] mm/hugetlb: define a generic fallback for is_hugepage_only_range() Andrew Morton
2020-06-03 23:01 ` [patch 077/131] mm/hugetlb: define a generic fallback for arch_clear_hugepage_flags() Andrew Morton
2020-06-03 23:01 ` [patch 078/131] mm: simplify calling a compound page destructor Andrew Morton
2020-06-03 23:01 ` [patch 079/131] mm/vmscan.c: use update_lru_size() in update_lru_sizes() Andrew Morton
2020-06-03 23:01 ` [patch 080/131] mm/vmscan: count layzfree pages and fix nr_isolated_* mismatch Andrew Morton
2020-06-03 23:01 ` [patch 081/131] mm/vmscan.c: change prototype for shrink_page_list Andrew Morton
2020-06-03 23:01 ` [patch 082/131] mm/vmscan: update the comment of should_continue_reclaim() Andrew Morton
2020-06-03 23:01 ` [patch 083/131] mm: fix NUMA node file count error in replace_page_cache() Andrew Morton
2020-06-03 23:01 ` [patch 084/131] mm: memcontrol: fix stat-corrupting race in charge moving Andrew Morton
2020-06-03 23:01 ` [patch 085/131] mm: memcontrol: drop @compound parameter from memcg charging API Andrew Morton
2020-06-03 23:01 ` [patch 086/131] mm: shmem: remove rare optimization when swapin races with hole punching Andrew Morton
2020-06-03 23:01 ` [patch 087/131] mm: memcontrol: move out cgroup swaprate throttling Andrew Morton
2020-06-03 23:01 ` [patch 088/131] mm: memcontrol: convert page cache to a new mem_cgroup_charge() API Andrew Morton
2020-06-03 23:01 ` [patch 089/131] mm: memcontrol: prepare uncharging for removal of private page type counters Andrew Morton
2020-06-03 23:01 ` [patch 090/131] mm: memcontrol: prepare move_account " Andrew Morton
2020-06-03 23:01 ` [patch 091/131] mm: memcontrol: prepare cgroup vmstat infrastructure for native anon counters Andrew Morton
2020-06-03 23:01 ` [patch 092/131] mm: memcontrol: switch to native NR_FILE_PAGES and NR_SHMEM counters Andrew Morton
2020-06-03 23:01 ` [patch 093/131] mm: memcontrol: switch to native NR_ANON_MAPPED counter Andrew Morton
2020-06-03 23:02 ` [patch 094/131] mm: memcontrol: switch to native NR_ANON_THPS counter Andrew Morton
2020-06-03 23:02 ` [patch 095/131] mm: memcontrol: convert anon and file-thp to new mem_cgroup_charge() API Andrew Morton
2020-06-03 23:02 ` [patch 096/131] mm: memcontrol: drop unused try/commit/cancel charge API Andrew Morton
2020-06-03 23:02 ` [patch 097/131] mm: memcontrol: prepare swap controller setup for integration Andrew Morton
2020-06-03 23:02 ` [patch 098/131] mm: memcontrol: make swap tracking an integral part of memory control Andrew Morton
2020-06-03 23:02 ` [patch 099/131] mm: memcontrol: charge swapin pages on instantiation Andrew Morton
2020-06-03 23:02 ` [patch 100/131] mm: memcontrol: document the new swap control behavior Andrew Morton
2020-06-03 23:02 ` [patch 101/131] mm: memcontrol: delete unused lrucare handling Andrew Morton
2020-06-03 23:02 ` [patch 102/131] mm: memcontrol: update page->mem_cgroup stability rules Andrew Morton
2020-06-03 23:02 ` [patch 103/131] mm: fix LRU balancing effect of new transparent huge pages Andrew Morton
2020-06-03 23:02 ` [patch 104/131] mm: keep separate anon and file statistics on page reclaim activity Andrew Morton
2020-06-03 23:02 ` [patch 105/131] mm: allow swappiness that prefers reclaiming anon over the file workingset Andrew Morton
2020-06-03 23:02 ` [patch 106/131] mm: fold and remove lru_cache_add_anon() and lru_cache_add_file() Andrew Morton
2020-06-03 23:02 ` [patch 107/131] mm: workingset: let cache workingset challenge anon Andrew Morton
2020-06-03 23:02 ` [patch 108/131] mm: remove use-once cache bias from LRU balancing Andrew Morton
2020-06-03 23:02 ` [patch 109/131] mm: vmscan: drop unnecessary div0 avoidance rounding in get_scan_count() Andrew Morton
2020-06-03 23:02 ` [patch 110/131] mm: base LRU balancing on an explicit cost model Andrew Morton
2020-06-03 23:02 ` [patch 111/131] mm: deactivations shouldn't bias the LRU balance Andrew Morton
2020-06-03 23:03 ` [patch 112/131] mm: only count actual rotations as LRU reclaim cost Andrew Morton
2020-06-03 23:03 ` [patch 113/131] mm: balance LRU lists based on relative thrashing Andrew Morton
2020-06-09 9:15 ` Alex Shi
2020-06-09 14:45 ` Johannes Weiner
2020-06-10 5:23 ` Joonsoo Kim
2020-06-11 3:28 ` Alex Shi
2020-06-03 23:03 ` [patch 114/131] mm: vmscan: determine anon/file pressure balance at the reclaim root Andrew Morton
2020-06-03 23:03 ` [patch 115/131] mm: vmscan: reclaim writepage is IO cost Andrew Morton
2020-06-03 23:03 ` [patch 116/131] mm: vmscan: limit the range of LRU type balancing Andrew Morton
2020-06-03 23:03 ` [patch 117/131] mm: swap: fix vmstats for huge pages Andrew Morton
2020-06-03 23:03 ` [patch 118/131] mm: swap: memcg: fix memcg stats " Andrew Morton
2020-06-03 23:03 ` [patch 119/131] tools/vm/page_owner_sort.c: filter out unneeded line Andrew Morton
2020-06-03 23:03 ` [patch 120/131] mm, mempolicy: fix up gup usage in lookup_node Andrew Morton
2020-06-03 23:03 ` [patch 121/131] include/linux/memblock.h: fix minor typo and unclear comment Andrew Morton
2020-06-03 23:03 ` [patch 122/131] sparc32: register memory occupied by kernel as memblock.memory Andrew Morton
2020-06-03 23:03 ` [patch 123/131] hugetlbfs: get unmapped area below TASK_UNMAPPED_BASE for hugetlbfs Andrew Morton
2020-06-03 23:03 ` [patch 124/131] mm: thp: don't need to drain lru cache when splitting and mlocking THP Andrew Morton
2020-06-03 23:03 ` [patch 125/131] powerpc/mm: drop platform defined pmd_mknotpresent() Andrew Morton
2020-06-03 23:03 ` [patch 126/131] mm/thp: rename pmd_mknotpresent() as pmd_mkinvalid() Andrew Morton
2020-06-03 23:03 ` [patch 127/131] drivers/base/memory.c: cache memory blocks in xarray to accelerate lookup Andrew Morton
2020-06-03 23:03 ` [patch 128/131] mm: add DEBUG_WX support Andrew Morton
2020-06-03 23:03 ` [patch 129/131] riscv: support DEBUG_WX Andrew Morton
2020-06-03 23:03 ` [patch 130/131] x86: mm: use ARCH_HAS_DEBUG_WX instead of arch defined Andrew Morton
2020-06-03 23:04 ` [patch 131/131] arm64: " Andrew Morton
2020-06-04 0:54 ` mmotm 2020-06-03-17-54 uploaded Andrew Morton
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=20200603225927.oWsDfB6-g%akpm@linux-foundation.org \
--to=akpm@linux-foundation.org \
--cc=dan.j.williams@intel.com \
--cc=daniel.m.jordan@oracle.com \
--cc=david@redhat.com \
--cc=jmorris@namei.org \
--cc=ktkhai@virtuozzo.com \
--cc=linux-mm@kvack.org \
--cc=mhocko@suse.com \
--cc=mm-commits@vger.kernel.org \
--cc=pankaj.gupta.linux@gmail.com \
--cc=pasha.tatashin@soleen.com \
--cc=sashal@kernel.org \
--cc=shile.zhang@linux.alibaba.com \
--cc=stable@vger.kernel.org \
--cc=torvalds@linux-foundation.org \
--cc=vbabka@suse.cz \
--cc=yiwei@redhat.com \
/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).