| Message ID | 20180613054107.GA5329@hori1.linux.bs1.fc.nec.co.jp (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Jun 13, 2018 at 05:41:08AM +0000, Naoya Horiguchi wrote: > Hi everyone, > > I wrote a patch for this issue. > There was a discussion about prechecking approach, but I finally found > out it's hard to make change on memblock after numa_init, so I take > another apporach (see patch description). > > I'm glad if you check that it works for you. > > Thanks, > Naoya Horiguchi > --- > From: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> > Date: Wed, 13 Jun 2018 12:43:27 +0900 > Subject: [PATCH] mm: zero remaining unavailable struct pages > > There is a kernel panic that is triggered when reading /proc/kpageflags > on the kernel booted with kernel parameter 'memmap=nn[KMG]!ss[KMG]': > > BUG: unable to handle kernel paging request at fffffffffffffffe > PGD 9b20e067 P4D 9b20e067 PUD 9b210067 PMD 0 > Oops: 0000 [#1] SMP PTI > CPU: 2 PID: 1728 Comm: page-types Not tainted 4.17.0-rc6-mm1-v4.17-rc6-180605-0816-00236-g2dfb086ef02c+ #160 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.fc28 04/01/2014 > RIP: 0010:stable_page_flags+0x27/0x3c0 > Code: 00 00 00 0f 1f 44 00 00 48 85 ff 0f 84 a0 03 00 00 41 54 55 49 89 fc 53 48 8b 57 08 48 8b 2f 48 8d 42 ff 83 e2 01 48 0f 44 c7 <48> 8b 00 f6 c4 01 0f 84 10 03 00 00 31 db 49 8b 54 24 08 4c 89 e7 > RSP: 0018:ffffbbd44111fde0 EFLAGS: 00010202 > RAX: fffffffffffffffe RBX: 00007fffffffeff9 RCX: 0000000000000000 > RDX: 0000000000000001 RSI: 0000000000000202 RDI: ffffed1182fff5c0 > RBP: ffffffffffffffff R08: 0000000000000001 R09: 0000000000000001 > R10: ffffbbd44111fed8 R11: 0000000000000000 R12: ffffed1182fff5c0 > R13: 00000000000bffd7 R14: 0000000002fff5c0 R15: ffffbbd44111ff10 > FS: 00007efc4335a500(0000) GS:ffff93a5bfc00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: fffffffffffffffe CR3: 00000000b2a58000 CR4: 00000000001406e0 > Call Trace: > kpageflags_read+0xc7/0x120 > proc_reg_read+0x3c/0x60 > __vfs_read+0x36/0x170 > vfs_read+0x89/0x130 > ksys_pread64+0x71/0x90 > do_syscall_64+0x5b/0x160 > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > RIP: 0033:0x7efc42e75e23 > Code: 09 00 ba 9f 01 00 00 e8 ab 81 f4 ff 66 2e 0f 1f 84 00 00 00 00 00 90 83 3d 29 0a 2d 00 00 75 13 49 89 ca b8 11 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 34 c3 48 83 ec 08 e8 db d3 01 00 48 89 04 24 > > According to kernel bisection, this problem became visible due to commit > f7f99100d8d9 which changes how struct pages are initialized. > > Memblock layout affects the pfn ranges covered by node/zone. Consider > that we have a VM with 2 NUMA nodes and each node has 4GB memory, and > the default (no memmap= given) memblock layout is like below: > > MEMBLOCK configuration: > memory size = 0x00000001fff75c00 reserved size = 0x000000000300c000 > memory.cnt = 0x4 > memory[0x0] [0x0000000000001000-0x000000000009efff], 0x000000000009e000 bytes on node 0 flags: 0x0 > memory[0x1] [0x0000000000100000-0x00000000bffd6fff], 0x00000000bfed7000 bytes on node 0 flags: 0x0 > memory[0x2] [0x0000000100000000-0x000000013fffffff], 0x0000000040000000 bytes on node 0 flags: 0x0 > memory[0x3] [0x0000000140000000-0x000000023fffffff], 0x0000000100000000 bytes on node 1 flags: 0x0 > ... > > If you give memmap=1G!4G (so it just covers memory[0x2]), > the range [0x100000000-0x13fffffff] is gone: > > MEMBLOCK configuration: > memory size = 0x00000001bff75c00 reserved size = 0x000000000300c000 > memory.cnt = 0x3 > memory[0x0] [0x0000000000001000-0x000000000009efff], 0x000000000009e000 bytes on node 0 flags: 0x0 > memory[0x1] [0x0000000000100000-0x00000000bffd6fff], 0x00000000bfed7000 bytes on node 0 flags: 0x0 > memory[0x2] [0x0000000140000000-0x000000023fffffff], 0x0000000100000000 bytes on node 1 flags: 0x0 > ... > > This causes shrinking node 0's pfn range because it is calculated by > the address range of memblock.memory. So some of struct pages in the > gap range are left uninitialized. > > We have a function zero_resv_unavail() which does zeroing the struct > pages outside memblock.memory, but currently it covers only the reserved > unavailable range (i.e. memblock.memory && !memblock.reserved). > This patch extends it to cover all unavailable range, which fixes > the reported issue. > > Fixes: f7f99100d8d9 ("mm: stop zeroing memory during allocation in vmemmap") > Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> > --- > include/linux/memblock.h | 16 ---------------- > mm/page_alloc.c | 33 ++++++++++++++++++++++++--------- > 2 files changed, 24 insertions(+), 25 deletions(-) > > diff --git a/include/linux/memblock.h b/include/linux/memblock.h > index ca59883c8364..f191e51c5d2a 100644 > --- a/include/linux/memblock.h > +++ b/include/linux/memblock.h > @@ -236,22 +236,6 @@ void __next_mem_pfn_range(int *idx, int nid, unsigned long *out_start_pfn, > for_each_mem_range_rev(i, &memblock.memory, &memblock.reserved, \ > nid, flags, p_start, p_end, p_nid) > > -/** > - * for_each_resv_unavail_range - iterate through reserved and unavailable memory > - * @i: u64 used as loop variable > - * @flags: pick from blocks based on memory attributes > - * @p_start: ptr to phys_addr_t for start address of the range, can be %NULL > - * @p_end: ptr to phys_addr_t for end address of the range, can be %NULL > - * > - * Walks over unavailable but reserved (reserved && !memory) areas of memblock. > - * Available as soon as memblock is initialized. > - * Note: because this memory does not belong to any physical node, flags and > - * nid arguments do not make sense and thus not exported as arguments. > - */ > -#define for_each_resv_unavail_range(i, p_start, p_end) \ > - for_each_mem_range(i, &memblock.reserved, &memblock.memory, \ > - NUMA_NO_NODE, MEMBLOCK_NONE, p_start, p_end, NULL) > - > static inline void memblock_set_region_flags(struct memblock_region *r, > unsigned long flags) > { > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 1772513358e9..098f7c2c127b 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -6487,25 +6487,40 @@ void __paginginit free_area_init_node(int nid, unsigned long *zones_size, > * struct pages which are reserved in memblock allocator and their fields > * may be accessed (for example page_to_pfn() on some configuration accesses > * flags). We must explicitly zero those struct pages. > + * > + * This function also addresses a similar issue where struct pages are left > + * uninitialized because the physical address range is not covered by > + * memblock.memory or memblock.reserved. That could happen when memblock > + * layout is manually configured via memmap=. > */ > void __paginginit zero_resv_unavail(void) > { > phys_addr_t start, end; > unsigned long pfn; > u64 i, pgcnt; > + phys_addr_t next = 0; > > /* > - * Loop through ranges that are reserved, but do not have reported > - * physical memory backing. > + * Loop through unavailable ranges not covered by memblock.memory. > */ > pgcnt = 0; > - for_each_resv_unavail_range(i, &start, &end) { > - for (pfn = PFN_DOWN(start); pfn < PFN_UP(end); pfn++) { > - if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) > - continue; > - mm_zero_struct_page(pfn_to_page(pfn)); > - pgcnt++; > + for_each_mem_range(i, &memblock.memory, NULL, > + NUMA_NO_NODE, MEMBLOCK_NONE, &start, &end, NULL) { > + if (next < start) { > + for (pfn = PFN_DOWN(next); pfn < PFN_UP(start); pfn++) { > + if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) > + continue; > + mm_zero_struct_page(pfn_to_page(pfn)); > + pgcnt++; > + } > } > + next = end; > + } > + for (pfn = PFN_DOWN(next); pfn < max_pfn; pfn++) { > + if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) > + continue; > + mm_zero_struct_page(pfn_to_page(pfn)); > + pgcnt++; > } Hi Naoya, Is the second loop really needed? AFAIK, max_pfn is set to the latest pfn of E820_TYPE_RAM type, and since you are going through all memory ranges within memblock.memory, and then assigning next = end, I think that at the time we are done with the first loop, next will always point to max_pfn (I only checked it for x86). Am I right o did I overlooked something? Besides that, I did some tests and I can no longer reproduce the error. So feel free to add: Tested-by: Oscar Salvador <osalvador@suse.de> > > /* > @@ -6516,7 +6531,7 @@ void __paginginit zero_resv_unavail(void) > * this code can be removed. > */ > if (pgcnt) > - pr_info("Reserved but unavailable: %lld pages", pgcnt); > + pr_info("Zeroed struct page in unavailable ranges: %lld pages", pgcnt); > } > #endif /* CONFIG_HAVE_MEMBLOCK */ > > -- > 2.7.4 > Thanks Best Regards Oscar Salvador
On Wed 13-06-18 05:41:08, Naoya Horiguchi wrote: [...] > From: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> > Date: Wed, 13 Jun 2018 12:43:27 +0900 > Subject: [PATCH] mm: zero remaining unavailable struct pages > > There is a kernel panic that is triggered when reading /proc/kpageflags > on the kernel booted with kernel parameter 'memmap=nn[KMG]!ss[KMG]': > > BUG: unable to handle kernel paging request at fffffffffffffffe > PGD 9b20e067 P4D 9b20e067 PUD 9b210067 PMD 0 > Oops: 0000 [#1] SMP PTI > CPU: 2 PID: 1728 Comm: page-types Not tainted 4.17.0-rc6-mm1-v4.17-rc6-180605-0816-00236-g2dfb086ef02c+ #160 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.fc28 04/01/2014 > RIP: 0010:stable_page_flags+0x27/0x3c0 > Code: 00 00 00 0f 1f 44 00 00 48 85 ff 0f 84 a0 03 00 00 41 54 55 49 89 fc 53 48 8b 57 08 48 8b 2f 48 8d 42 ff 83 e2 01 48 0f 44 c7 <48> 8b 00 f6 c4 01 0f 84 10 03 00 00 31 db 49 8b 54 24 08 4c 89 e7 > RSP: 0018:ffffbbd44111fde0 EFLAGS: 00010202 > RAX: fffffffffffffffe RBX: 00007fffffffeff9 RCX: 0000000000000000 > RDX: 0000000000000001 RSI: 0000000000000202 RDI: ffffed1182fff5c0 > RBP: ffffffffffffffff R08: 0000000000000001 R09: 0000000000000001 > R10: ffffbbd44111fed8 R11: 0000000000000000 R12: ffffed1182fff5c0 > R13: 00000000000bffd7 R14: 0000000002fff5c0 R15: ffffbbd44111ff10 > FS: 00007efc4335a500(0000) GS:ffff93a5bfc00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: fffffffffffffffe CR3: 00000000b2a58000 CR4: 00000000001406e0 > Call Trace: > kpageflags_read+0xc7/0x120 > proc_reg_read+0x3c/0x60 > __vfs_read+0x36/0x170 > vfs_read+0x89/0x130 > ksys_pread64+0x71/0x90 > do_syscall_64+0x5b/0x160 > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > RIP: 0033:0x7efc42e75e23 > Code: 09 00 ba 9f 01 00 00 e8 ab 81 f4 ff 66 2e 0f 1f 84 00 00 00 00 00 90 83 3d 29 0a 2d 00 00 75 13 49 89 ca b8 11 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 34 c3 48 83 ec 08 e8 db d3 01 00 48 89 04 24 > > According to kernel bisection, this problem became visible due to commit > f7f99100d8d9 which changes how struct pages are initialized. > > Memblock layout affects the pfn ranges covered by node/zone. Consider > that we have a VM with 2 NUMA nodes and each node has 4GB memory, and > the default (no memmap= given) memblock layout is like below: > > MEMBLOCK configuration: > memory size = 0x00000001fff75c00 reserved size = 0x000000000300c000 > memory.cnt = 0x4 > memory[0x0] [0x0000000000001000-0x000000000009efff], 0x000000000009e000 bytes on node 0 flags: 0x0 > memory[0x1] [0x0000000000100000-0x00000000bffd6fff], 0x00000000bfed7000 bytes on node 0 flags: 0x0 > memory[0x2] [0x0000000100000000-0x000000013fffffff], 0x0000000040000000 bytes on node 0 flags: 0x0 > memory[0x3] [0x0000000140000000-0x000000023fffffff], 0x0000000100000000 bytes on node 1 flags: 0x0 > ... > > If you give memmap=1G!4G (so it just covers memory[0x2]), > the range [0x100000000-0x13fffffff] is gone: > > MEMBLOCK configuration: > memory size = 0x00000001bff75c00 reserved size = 0x000000000300c000 > memory.cnt = 0x3 > memory[0x0] [0x0000000000001000-0x000000000009efff], 0x000000000009e000 bytes on node 0 flags: 0x0 > memory[0x1] [0x0000000000100000-0x00000000bffd6fff], 0x00000000bfed7000 bytes on node 0 flags: 0x0 > memory[0x2] [0x0000000140000000-0x000000023fffffff], 0x0000000100000000 bytes on node 1 flags: 0x0 > ... > > This causes shrinking node 0's pfn range because it is calculated by > the address range of memblock.memory. So some of struct pages in the > gap range are left uninitialized. > > We have a function zero_resv_unavail() which does zeroing the struct > pages outside memblock.memory, but currently it covers only the reserved > unavailable range (i.e. memblock.memory && !memblock.reserved). > This patch extends it to cover all unavailable range, which fixes > the reported issue. Thanks for pin pointing this down Naoya! I am wondering why we cannot simply mark the excluded ranges to be reserved instead.
On Wed, Jun 13, 2018 at 10:40:32AM +0200, Oscar Salvador wrote: > On Wed, Jun 13, 2018 at 05:41:08AM +0000, Naoya Horiguchi wrote: > > Hi everyone, > > > > I wrote a patch for this issue. > > There was a discussion about prechecking approach, but I finally found > > out it's hard to make change on memblock after numa_init, so I take > > another apporach (see patch description). > > > > I'm glad if you check that it works for you. > > > > Thanks, > > Naoya Horiguchi > > --- > > From: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> > > Date: Wed, 13 Jun 2018 12:43:27 +0900 > > Subject: [PATCH] mm: zero remaining unavailable struct pages > > > > There is a kernel panic that is triggered when reading /proc/kpageflags > > on the kernel booted with kernel parameter 'memmap=nn[KMG]!ss[KMG]': > > > > BUG: unable to handle kernel paging request at fffffffffffffffe > > PGD 9b20e067 P4D 9b20e067 PUD 9b210067 PMD 0 > > Oops: 0000 [#1] SMP PTI > > CPU: 2 PID: 1728 Comm: page-types Not tainted 4.17.0-rc6-mm1-v4.17-rc6-180605-0816-00236-g2dfb086ef02c+ #160 > > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.fc28 04/01/2014 > > RIP: 0010:stable_page_flags+0x27/0x3c0 > > Code: 00 00 00 0f 1f 44 00 00 48 85 ff 0f 84 a0 03 00 00 41 54 55 49 89 fc 53 48 8b 57 08 48 8b 2f 48 8d 42 ff 83 e2 01 48 0f 44 c7 <48> 8b 00 f6 c4 01 0f 84 10 03 00 00 31 db 49 8b 54 24 08 4c 89 e7 > > RSP: 0018:ffffbbd44111fde0 EFLAGS: 00010202 > > RAX: fffffffffffffffe RBX: 00007fffffffeff9 RCX: 0000000000000000 > > RDX: 0000000000000001 RSI: 0000000000000202 RDI: ffffed1182fff5c0 > > RBP: ffffffffffffffff R08: 0000000000000001 R09: 0000000000000001 > > R10: ffffbbd44111fed8 R11: 0000000000000000 R12: ffffed1182fff5c0 > > R13: 00000000000bffd7 R14: 0000000002fff5c0 R15: ffffbbd44111ff10 > > FS: 00007efc4335a500(0000) GS:ffff93a5bfc00000(0000) knlGS:0000000000000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: fffffffffffffffe CR3: 00000000b2a58000 CR4: 00000000001406e0 > > Call Trace: > > kpageflags_read+0xc7/0x120 > > proc_reg_read+0x3c/0x60 > > __vfs_read+0x36/0x170 > > vfs_read+0x89/0x130 > > ksys_pread64+0x71/0x90 > > do_syscall_64+0x5b/0x160 > > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > RIP: 0033:0x7efc42e75e23 > > Code: 09 00 ba 9f 01 00 00 e8 ab 81 f4 ff 66 2e 0f 1f 84 00 00 00 00 00 90 83 3d 29 0a 2d 00 00 75 13 49 89 ca b8 11 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 34 c3 48 83 ec 08 e8 db d3 01 00 48 89 04 24 > > > > According to kernel bisection, this problem became visible due to commit > > f7f99100d8d9 which changes how struct pages are initialized. > > > > Memblock layout affects the pfn ranges covered by node/zone. Consider > > that we have a VM with 2 NUMA nodes and each node has 4GB memory, and > > the default (no memmap= given) memblock layout is like below: > > > > MEMBLOCK configuration: > > memory size = 0x00000001fff75c00 reserved size = 0x000000000300c000 > > memory.cnt = 0x4 > > memory[0x0] [0x0000000000001000-0x000000000009efff], 0x000000000009e000 bytes on node 0 flags: 0x0 > > memory[0x1] [0x0000000000100000-0x00000000bffd6fff], 0x00000000bfed7000 bytes on node 0 flags: 0x0 > > memory[0x2] [0x0000000100000000-0x000000013fffffff], 0x0000000040000000 bytes on node 0 flags: 0x0 > > memory[0x3] [0x0000000140000000-0x000000023fffffff], 0x0000000100000000 bytes on node 1 flags: 0x0 > > ... > > > > If you give memmap=1G!4G (so it just covers memory[0x2]), > > the range [0x100000000-0x13fffffff] is gone: > > > > MEMBLOCK configuration: > > memory size = 0x00000001bff75c00 reserved size = 0x000000000300c000 > > memory.cnt = 0x3 > > memory[0x0] [0x0000000000001000-0x000000000009efff], 0x000000000009e000 bytes on node 0 flags: 0x0 > > memory[0x1] [0x0000000000100000-0x00000000bffd6fff], 0x00000000bfed7000 bytes on node 0 flags: 0x0 > > memory[0x2] [0x0000000140000000-0x000000023fffffff], 0x0000000100000000 bytes on node 1 flags: 0x0 > > ... > > > > This causes shrinking node 0's pfn range because it is calculated by > > the address range of memblock.memory. So some of struct pages in the > > gap range are left uninitialized. > > > > We have a function zero_resv_unavail() which does zeroing the struct > > pages outside memblock.memory, but currently it covers only the reserved > > unavailable range (i.e. memblock.memory && !memblock.reserved). > > This patch extends it to cover all unavailable range, which fixes > > the reported issue. > > > > Fixes: f7f99100d8d9 ("mm: stop zeroing memory during allocation in vmemmap") > > Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> > > --- > > include/linux/memblock.h | 16 ---------------- > > mm/page_alloc.c | 33 ++++++++++++++++++++++++--------- > > 2 files changed, 24 insertions(+), 25 deletions(-) > > > > diff --git a/include/linux/memblock.h b/include/linux/memblock.h > > index ca59883c8364..f191e51c5d2a 100644 > > --- a/include/linux/memblock.h > > +++ b/include/linux/memblock.h > > @@ -236,22 +236,6 @@ void __next_mem_pfn_range(int *idx, int nid, unsigned long *out_start_pfn, > > for_each_mem_range_rev(i, &memblock.memory, &memblock.reserved, \ > > nid, flags, p_start, p_end, p_nid) > > > > -/** > > - * for_each_resv_unavail_range - iterate through reserved and unavailable memory > > - * @i: u64 used as loop variable > > - * @flags: pick from blocks based on memory attributes > > - * @p_start: ptr to phys_addr_t for start address of the range, can be %NULL > > - * @p_end: ptr to phys_addr_t for end address of the range, can be %NULL > > - * > > - * Walks over unavailable but reserved (reserved && !memory) areas of memblock. > > - * Available as soon as memblock is initialized. > > - * Note: because this memory does not belong to any physical node, flags and > > - * nid arguments do not make sense and thus not exported as arguments. > > - */ > > -#define for_each_resv_unavail_range(i, p_start, p_end) \ > > - for_each_mem_range(i, &memblock.reserved, &memblock.memory, \ > > - NUMA_NO_NODE, MEMBLOCK_NONE, p_start, p_end, NULL) > > - > > static inline void memblock_set_region_flags(struct memblock_region *r, > > unsigned long flags) > > { > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > > index 1772513358e9..098f7c2c127b 100644 > > --- a/mm/page_alloc.c > > +++ b/mm/page_alloc.c > > @@ -6487,25 +6487,40 @@ void __paginginit free_area_init_node(int nid, unsigned long *zones_size, > > * struct pages which are reserved in memblock allocator and their fields > > * may be accessed (for example page_to_pfn() on some configuration accesses > > * flags). We must explicitly zero those struct pages. > > + * > > + * This function also addresses a similar issue where struct pages are left > > + * uninitialized because the physical address range is not covered by > > + * memblock.memory or memblock.reserved. That could happen when memblock > > + * layout is manually configured via memmap=. > > */ > > void __paginginit zero_resv_unavail(void) > > { > > phys_addr_t start, end; > > unsigned long pfn; > > u64 i, pgcnt; > > + phys_addr_t next = 0; > > > > /* > > - * Loop through ranges that are reserved, but do not have reported > > - * physical memory backing. > > + * Loop through unavailable ranges not covered by memblock.memory. > > */ > > pgcnt = 0; > > - for_each_resv_unavail_range(i, &start, &end) { > > - for (pfn = PFN_DOWN(start); pfn < PFN_UP(end); pfn++) { > > - if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) > > - continue; > > - mm_zero_struct_page(pfn_to_page(pfn)); > > - pgcnt++; > > + for_each_mem_range(i, &memblock.memory, NULL, > > + NUMA_NO_NODE, MEMBLOCK_NONE, &start, &end, NULL) { > > + if (next < start) { > > + for (pfn = PFN_DOWN(next); pfn < PFN_UP(start); pfn++) { > > + if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) > > + continue; > > + mm_zero_struct_page(pfn_to_page(pfn)); > > + pgcnt++; > > + } > > } > > + next = end; > > + } > > + for (pfn = PFN_DOWN(next); pfn < max_pfn; pfn++) { > > + if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) > > + continue; > > + mm_zero_struct_page(pfn_to_page(pfn)); > > + pgcnt++; > > } > > Hi Naoya, > > Is the second loop really needed? > > AFAIK, max_pfn is set to the latest pfn of E820_TYPE_RAM type, and since > you are going through all memory ranges within memblock.memory, and then assigning next = end, > I think that at the time we are done with the first loop, next will always point > to max_pfn (I only checked it for x86). > Am I right o did I overlooked something? Hi Oscar, Thank you for the comment. Some archs do set max_pfn to end pfn of E820_TYPE_RAM, but some archs (s390, arm, mips, ...) seem to determine max_pfn in their own way. I'm not sure this problem is visible in such archs. > > Besides that, I did some tests and I can no longer reproduce the error. > So feel free to add: > > Tested-by: Oscar Salvador <osalvador@suse.de> Thank you! - Naoya > > > > > /* > > @@ -6516,7 +6531,7 @@ void __paginginit zero_resv_unavail(void) > > * this code can be removed. > > */ > > if (pgcnt) > > - pr_info("Reserved but unavailable: %lld pages", pgcnt); > > + pr_info("Zeroed struct page in unavailable ranges: %lld pages", pgcnt); > > } > > #endif /* CONFIG_HAVE_MEMBLOCK */ > > > > -- > > 2.7.4 > > > > Thanks > > Best Regards > Oscar Salvador >
diff --git a/include/linux/memblock.h b/include/linux/memblock.h index ca59883c8364..f191e51c5d2a 100644 --- a/include/linux/memblock.h +++ b/include/linux/memblock.h @@ -236,22 +236,6 @@ void __next_mem_pfn_range(int *idx, int nid, unsigned long *out_start_pfn, for_each_mem_range_rev(i, &memblock.memory, &memblock.reserved, \ nid, flags, p_start, p_end, p_nid) -/** - * for_each_resv_unavail_range - iterate through reserved and unavailable memory - * @i: u64 used as loop variable - * @flags: pick from blocks based on memory attributes - * @p_start: ptr to phys_addr_t for start address of the range, can be %NULL - * @p_end: ptr to phys_addr_t for end address of the range, can be %NULL - * - * Walks over unavailable but reserved (reserved && !memory) areas of memblock. - * Available as soon as memblock is initialized. - * Note: because this memory does not belong to any physical node, flags and - * nid arguments do not make sense and thus not exported as arguments. - */ -#define for_each_resv_unavail_range(i, p_start, p_end) \ - for_each_mem_range(i, &memblock.reserved, &memblock.memory, \ - NUMA_NO_NODE, MEMBLOCK_NONE, p_start, p_end, NULL) - static inline void memblock_set_region_flags(struct memblock_region *r, unsigned long flags) { diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 1772513358e9..098f7c2c127b 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -6487,25 +6487,40 @@ void __paginginit free_area_init_node(int nid, unsigned long *zones_size, * struct pages which are reserved in memblock allocator and their fields * may be accessed (for example page_to_pfn() on some configuration accesses * flags). We must explicitly zero those struct pages. + * + * This function also addresses a similar issue where struct pages are left + * uninitialized because the physical address range is not covered by + * memblock.memory or memblock.reserved. That could happen when memblock + * layout is manually configured via memmap=. */ void __paginginit zero_resv_unavail(void) { phys_addr_t start, end; unsigned long pfn; u64 i, pgcnt; + phys_addr_t next = 0; /* - * Loop through ranges that are reserved, but do not have reported - * physical memory backing. + * Loop through unavailable ranges not covered by memblock.memory. */ pgcnt = 0; - for_each_resv_unavail_range(i, &start, &end) { - for (pfn = PFN_DOWN(start); pfn < PFN_UP(end); pfn++) { - if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) - continue; - mm_zero_struct_page(pfn_to_page(pfn)); - pgcnt++; + for_each_mem_range(i, &memblock.memory, NULL, + NUMA_NO_NODE, MEMBLOCK_NONE, &start, &end, NULL) { + if (next < start) { + for (pfn = PFN_DOWN(next); pfn < PFN_UP(start); pfn++) { + if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) + continue; + mm_zero_struct_page(pfn_to_page(pfn)); + pgcnt++; + } } + next = end; + } + for (pfn = PFN_DOWN(next); pfn < max_pfn; pfn++) { + if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) + continue; + mm_zero_struct_page(pfn_to_page(pfn)); + pgcnt++; } /* @@ -6516,7 +6531,7 @@ void __paginginit zero_resv_unavail(void) * this code can be removed. */ if (pgcnt) - pr_info("Reserved but unavailable: %lld pages", pgcnt); + pr_info("Zeroed struct page in unavailable ranges: %lld pages", pgcnt); } #endif /* CONFIG_HAVE_MEMBLOCK */