Messages in this thread Patch in this message | | | Date | Sun, 24 May 2020 15:32:56 +0300 | From | Mike Rapoport <> | Subject | Re: [PATCH v5 04/18] sparc32: mm: Reduce allocation size for PMD and PTE tables |
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On Thu, May 21, 2020 at 04:02:11PM -0700, Guenter Roeck wrote: > On 5/20/20 12:51 PM, Mike Rapoport wrote: > > On Wed, May 20, 2020 at 12:03:31PM -0700, Guenter Roeck wrote: > >> On 5/20/20 10:03 AM, Mike Rapoport wrote: > >>> On Mon, May 18, 2020 at 09:37:15AM +0100, Will Deacon wrote: > >>>> On Sat, May 16, 2020 at 05:07:50PM -0700, Guenter Roeck wrote: > >>>>> On Sat, May 16, 2020 at 05:00:50PM -0700, Guenter Roeck wrote: > >>>>>> On Mon, May 11, 2020 at 09:41:36PM +0100, Will Deacon wrote: > >>>>>>> Now that the page table allocator can free page table allocations > >>>>>>> smaller than PAGE_SIZE, reduce the size of the PMD and PTE allocations > >>>>>>> to avoid needlessly wasting memory. > >>>>>>> > >>>>>>> Cc: "David S. Miller" <davem@davemloft.net> > >>>>>>> Cc: Peter Zijlstra <peterz@infradead.org> > >>>>>>> Signed-off-by: Will Deacon <will@kernel.org> > >>>>>> > >>>>>> Something in the sparc32 patches in linux-next causes all my sparc32 emulations > >>>>>> to crash. bisect points to this patch, but reverting it doesn't help, and neither > >>>>>> does reverting the rest of the series. > >>>>>> > >>>>> Actually, turns out I see the same pattern (lots of scheduling while atomic > >>>>> followed by 'killing interrupt handler' in cryptomgr_test) with several > >>>>> powerpc boot tests. I am currently bisecting those crashes. I'll report > >>>>> the results here as well as soon as I have it. > >>>> > >>>> FWIW, I retested my sparc32 patches with PREEMPT=y and I don't see any > >>>> issues. However, linux-next is a different story, where I don't get very far > >>>> at all: > >>>> > >>>> BUG: Bad page state in process swapper pfn:005b4 > >> > >> With above patch applied on top of Ira's patch, I get: > >> > >> BUG: spinlock recursion on CPU#0, S01syslogd/139 > >> lock: 0xf5448350, .magic: dead4ead, .owner: S01syslogd/139, .owner_cpu: 0 > >> CPU: 0 PID: 139 Comm: S01syslogd Not tainted 5.7.0-rc6-next-20200518-00002-gb178d2d56f29-dirty #1 > >> [f0067a64 : > >> do_raw_spin_lock+0xa8/0xd8 ] > >> [f00d5034 : > >> copy_page_range+0x328/0x804 ] > >> [f0025be4 : > >> dup_mm+0x334/0x434 ] > >> [f0027124 : > >> copy_process+0x1224/0x12b0 ] > >> [f0027344 : > >> _do_fork+0x54/0x30c ] > >> [f0027670 : > >> do_fork+0x5c/0x6c ] > >> [f000de44 : > >> sparc_do_fork+0x18/0x38 ] > >> [f000b7f4 : > >> do_syscall+0x34/0x40 ] > >> [5010cd4c : > >> 0x5010cd4c ] > >> > >> Looks like yet another problem. > > > > I've checked the patch above on top of the mmots which already has Ira's > > patches and it booted fine. I've used sparc32_defconfig to build the > > kernel and qemu-system-sparc with default machine and CPU. > > > > Try sparc32_defconfig+SMP.
I see a differernt problem, but this could be related:
INIT: version 2.86 booting rcu: INFO: rcu_sched detected stalls on CPUs/tasks: (detected by 0, t=5252 jiffies, g=-935, q=3) rcu: All QSes seen, last rcu_sched kthread activity 5252 (-68674--73926), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_sched kthread starved for 5252 jiffies! g-935 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: Unless rcu_sched kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: rcu_sched R running task 0 10 2 0x00000000
I'm running a bit old debian [1] with qemu-img-sparc.
My bisect pointed at commit 8c8f3156dd40 ("sparc32: mm: Reduce allocation size for PMD and PTE tables"). The commit ID is valid for next-20200522.
If I revert this commit and fixup the page table initialization [2] I've broken, the build with CONFIG_SMP=n works fine, but the build with CONFIG_SMP=y does not work even if I add nosmp to the kernel command line.
[1] https://people.debian.org/~aurel32/qemu/sparc/debian_etch_sparc_small.qcow2 [2] sparc32 meminit fixup:
diff --git a/arch/sparc/mm/init_32.c b/arch/sparc/mm/init_32.c index e45160839f79..eb2946b1df8a 100644 --- a/arch/sparc/mm/init_32.c +++ b/arch/sparc/mm/init_32.c @@ -192,6 +192,7 @@ unsigned long __init bootmem_init(unsigned long *pages_avail) /* Reserve the kernel text/data/bss. */ size = (start_pfn << PAGE_SHIFT) - phys_base; memblock_reserve(phys_base, size); + memblock_add(phys_base, size); size = memblock_phys_mem_size() - memblock_reserved_size(); *pages_avail = (size >> PAGE_SHIFT) - high_pages; diff --git a/arch/sparc/mm/srmmu.c b/arch/sparc/mm/srmmu.c index 75b56bdd38ef..6cb1ea2d2b5c 100644 --- a/arch/sparc/mm/srmmu.c +++ b/arch/sparc/mm/srmmu.c @@ -304,7 +304,7 @@ static void __init srmmu_nocache_init(void) pgd = pgd_offset_k(vaddr); p4d = p4d_offset(__nocache_fix(pgd), vaddr); pud = pud_offset(__nocache_fix(p4d), vaddr); - pmd = pmd_offset(__nocache_fix(pud), vaddr); + pmd = pmd_offset(__nocache_fix(pgd), vaddr); pte = pte_offset_kernel(__nocache_fix(pmd), vaddr); pteval = ((paddr >> 4) | SRMMU_ET_PTE | SRMMU_PRIV); > Guenter
-- Sincerely yours, Mike.
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