From: Josef Bacik <josef@toxicpanda.com>
To: kernel-team@fb.com, linux-kernel@vger.kernel.org,
hannes@cmpxchg.org, tj@kernel.org, linux-fsdevel@vger.kernel.org,
akpm@linux-foundation.org, riel@redhat.com, linux-mm@kvack.org,
linux-btrfs@vger.kernel.org
Cc: Johannes Weiner <jweiner@fb.com>
Subject: [PATCH 4/9] mm: drop mmap_sem for swap read IO submission
Date: Wed, 26 Sep 2018 17:08:51 -0400 [thread overview]
Message-ID: <20180926210856.7895-5-josef@toxicpanda.com> (raw)
In-Reply-To: <20180926210856.7895-1-josef@toxicpanda.com>
From: Johannes Weiner <jweiner@fb.com>
We don't need to hold the mmap_sem while we're doing the IO, simply drop
it and retry appropriately.
Signed-off-by: Johannes Weiner <jweiner@fb.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
mm/page_io.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/mm/page_io.c b/mm/page_io.c
index aafd19ec1db4..bf21b56a964e 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -365,6 +365,20 @@ int swap_readpage(struct page *page, bool synchronous)
goto out;
}
+ /*
+ * XXX:
+ *
+ * Propagate mm->mmap_sem into this function. Then:
+ *
+ * get_file(sis->swap_file)
+ * up_read(mm->mmap_sem)
+ * submit io request
+ * fput
+ *
+ * After mmap_sem is dropped, sis is no longer valid. Go
+ * through swap_file->blah->bdev.
+ */
+
if (sis->flags & SWP_FILE) {
struct file *swap_file = sis->swap_file;
struct address_space *mapping = swap_file->f_mapping;
--
2.14.3
next prev parent reply other threads:[~2018-09-26 21:09 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-26 21:08 [RFC][PATCH 0/9][V2] drop the mmap_sem when doing IO in the fault path Josef Bacik
2018-09-26 21:08 ` [PATCH 1/9] mm: infrastructure for page fault page caching Josef Bacik
2018-09-27 16:24 ` Matthew Wilcox
2018-09-26 21:08 ` [PATCH 2/9] mm: drop mmap_sem for page cache read IO submission Josef Bacik
2018-09-26 21:08 ` [PATCH 3/9] mm: clean up swapcache lookup and creation function names Josef Bacik
2018-09-26 21:08 ` Josef Bacik [this message]
2018-09-26 21:08 ` [PATCH 5/9] mm: drop the mmap_sem in all read fault cases Josef Bacik
2018-09-26 21:08 ` [PATCH 6/9] mm: use the cached page for filemap_fault Josef Bacik
2018-09-26 21:08 ` [PATCH 7/9] mm: add a flag to indicate we used a cached page Josef Bacik
2018-09-26 21:08 ` [PATCH 8/9] mm: allow ->page_mkwrite to do retries Josef Bacik
2018-09-26 21:08 ` [PATCH 9/9] btrfs: drop mmap_sem in mkwrite for btrfs Josef Bacik
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