From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Ebru Akagunduz <ebru.akagunduz@gmail.com>,
Vlastimil Babka <vbabka@suse.cz>,
Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@kernel.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Stephen Rothwell <sfr@canb.auug.org.au>,
Andrea Arcangeli <aarcange@redhat.com>,
Rik van Riel <riel@redhat.com>,
linux-mm@kvack.org, linux-next@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [linux-next: Tree for Jun 1] __khugepaged_exit rwsem_down_write_failed lockup
Date: Fri, 3 Jun 2016 13:14:19 +0900 [thread overview]
Message-ID: <20160603041351.GA10882@swordfish> (raw)
In-Reply-To: <20160603012919.GB464@swordfish>
On (06/03/16 10:29), Sergey Senozhatsky wrote:
> > if (allocstall == curr_allocstall && swap != 0) {
> > if (!__collapse_huge_page_swapin(mm, vma, address, pmd)) {
> > {
> > : if (ret & VM_FAULT_RETRY) {
> > : down_read(&mm->mmap_sem);
> > : ^^^^^^^^^
>
> oh... it's in a loop
>
> for (_address = address; _address < address + HPAGE_PMD_NR*PAGE_SIZE;
> pte++, _address += PAGE_SIZE) {
> ret = do_swap_page()
> if (ret & VM_FAULT_RETRY) {
> down_read(&mm->mmap_sem);
> ^^^^^^^^^
> ...
> }
> }
>
> so there can be multiple sem->count++ in __collapse_huge_page_swapin(),
> and you don't know how many sem->count-- you need to do later? is this
> correct or am I hallucinating?
No, I was wrong, sorry for the noise.
it's getting unlocked in
__collapse_huge_page_swapin()
do_swap_page()
lock_page_or_retry()
if (flags & FAULT_FLAG_ALLOW_RETRY)
up_read(&mm->mmap_sem);
return VM_FAULT_RETRY
-ss
next prev parent reply other threads:[~2016-06-03 4:15 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-01 3:11 linux-next: Tree for Jun 1 Stephen Rothwell
2016-06-02 1:48 ` [linux-next: Tree for Jun 1] __khugepaged_exit rwsem_down_write_failed lockup Sergey Senozhatsky
2016-06-02 9:21 ` Michal Hocko
2016-06-02 12:08 ` Sergey Senozhatsky
2016-06-02 12:21 ` Michal Hocko
2016-06-03 13:51 ` Andrea Arcangeli
2016-06-03 14:46 ` Michal Hocko
2016-06-03 15:10 ` Andrea Arcangeli
2016-06-07 7:34 ` Michal Hocko
2016-06-08 8:19 ` Vlastimil Babka
2016-06-03 7:15 ` Sergey Senozhatsky
2016-06-03 7:25 ` Michal Hocko
2016-06-03 8:43 ` Sergey Senozhatsky
2016-06-03 9:55 ` Michal Hocko
2016-06-03 10:05 ` Michal Hocko
2016-06-03 13:38 ` Sergey Senozhatsky
2016-06-03 13:45 ` Michal Hocko
2016-06-03 13:49 ` Michal Hocko
2016-06-04 7:51 ` Sergey Senozhatsky
2016-06-06 8:39 ` Michal Hocko
2016-06-02 13:24 ` Vlastimil Babka
2016-06-02 18:58 ` Ebru Akagunduz
2016-06-03 1:00 ` Sergey Senozhatsky
2016-06-03 1:29 ` Sergey Senozhatsky
2016-06-03 4:14 ` Sergey Senozhatsky [this message]
2016-06-03 12:28 ` [PATCH] mm, thp: fix locking inconsistency in collapse_huge_page Ebru Akagunduz
2016-06-06 13:05 ` Vlastimil Babka
2016-06-09 3:51 ` Sergey Senozhatsky
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