[merged] mm-vunmap-add-cond_resched-in-vunmap_pmd_range.patch removed from -mm tree

[merged] mm-vunmap-add-cond_resched-in-vunmap_pmd_range.patch removed from -mm tree

[akpm]

The patch titled
     Subject: mm/vunmap: add cond_resched() in vunmap_pmd_range
has been removed from the -mm tree.  Its filename was
     mm-vunmap-add-cond_resched-in-vunmap_pmd_range.patch

This patch was dropped because it was merged into mainline or a subsystem tree

------------------------------------------------------
From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Subject: mm/vunmap: add cond_resched() in vunmap_pmd_range

Like zap_pte_range add cond_resched so that we can avoid softlockups as
reported below.  On non-preemptible kernel with large I/O map region (like
the one we get when using persistent memory with sector mode), an unmap of
the namespace can report below softlockups.

22724.027334] watchdog: BUG: soft lockup - CPU#49 stuck for 23s! [ndctl:50777]
 NIP [c0000000000dc224] plpar_hcall+0x38/0x58
 LR [c0000000000d8898] pSeries_lpar_hpte_invalidate+0x68/0xb0
 Call Trace:
 [c0000004e87a7780] [c0000004fb197c00] 0xc0000004fb197c00 (unreliable)
 [c0000004e87a7810] [c00000000007f4e4] flush_hash_page+0x114/0x200
 [c0000004e87a7890] [c0000000000833cc] hpte_need_flush+0x2dc/0x540
 [c0000004e87a7950] [c0000000003f5798] vunmap_page_range+0x538/0x6f0
 [c0000004e87a7a70] [c0000000003f76d0] free_unmap_vmap_area+0x30/0x70
 [c0000004e87a7aa0] [c0000000003f7a6c] remove_vm_area+0xfc/0x140
 [c0000004e87a7ad0] [c0000000003f7dd8] __vunmap+0x68/0x270
 [c0000004e87a7b50] [c000000000079de4] __iounmap.part.0+0x34/0x60
 [c0000004e87a7bb0] [c000000000376394] memunmap+0x54/0x70
 [c0000004e87a7bd0] [c000000000881d7c] release_nodes+0x28c/0x300
 [c0000004e87a7c40] [c00000000087a65c] device_release_driver_internal+0x16c/0x280
 [c0000004e87a7c80] [c000000000876fc4] unbind_store+0x124/0x170
 [c0000004e87a7cd0] [c000000000875be4] drv_attr_store+0x44/0x60
 [c0000004e87a7cf0] [c00000000057c734] sysfs_kf_write+0x64/0x90
 [c0000004e87a7d10] [c00000000057bc10] kernfs_fop_write+0x1b0/0x290
 [c0000004e87a7d60] [c000000000488e6c] __vfs_write+0x3c/0x70
 [c0000004e87a7d80] [c00000000048c868] vfs_write+0xd8/0x260
 [c0000004e87a7dd0] [c00000000048ccac] ksys_write+0xdc/0x130
 [c0000004e87a7e20] [c00000000000b588] system_call+0x5c/0x70

Link: http://lkml.kernel.org/r/20200807075933.310240-1-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reported-by: Harish Sriram <harish@linux.ibm.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/vmalloc.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/mm/vmalloc.c~mm-vunmap-add-cond_resched-in-vunmap_pmd_range
+++ a/mm/vmalloc.c
@@ -104,6 +104,8 @@ static void vunmap_pmd_range(pud_t *pud,
 		if (pmd_none_or_clear_bad(pmd))
 			continue;
 		vunmap_pte_range(pmd, addr, next, mask);
+
+		cond_resched();
 	} while (pmd++, addr = next, addr != end);
 }
 
_

Patches currently in -mm which might be from aneesh.kumar@linux.ibm.com are