From: Michal Hocko <mhocko@kernel.org>
To: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linux-xfs@vger.kernel.org, dm-devel@redhat.com,
Mikulas Patocka <mpatocka@redhat.com>,
Jens Axboe <axboe@kernel.dk>, NeilBrown <neilb@suse.de>
Subject: Re: [PATCH 6/6] mm: Add memalloc_nowait
Date: Thu, 25 Jun 2020 14:40:17 +0200 [thread overview]
Message-ID: <20200625124017.GL1320@dhcp22.suse.cz> (raw)
In-Reply-To: <20200625113122.7540-7-willy@infradead.org>
On Thu 25-06-20 12:31:22, Matthew Wilcox wrote:
> Similar to memalloc_noio() and memalloc_nofs(), memalloc_nowait()
> guarantees we will not sleep to reclaim memory. Use it to simplify
> dm-bufio's allocations.
memalloc_nowait is a good idea! I suspect the primary usecase would be
vmalloc.
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
[...]
> @@ -877,7 +857,9 @@ static struct dm_buffer *__alloc_buffer_wait_no_callback(struct dm_bufio_client
> */
> while (1) {
> if (dm_bufio_cache_size_latch != 1) {
> - b = alloc_buffer(c, GFP_NOWAIT | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN);
> + unsigned nowait_flag = memalloc_nowait_save();
> + b = alloc_buffer(c, GFP_KERNEL | __GFP_NOMEMALLOC | __GFP_NOWARN);
> + memalloc_nowait_restore(nowait_flag);
This looks confusing though. I am not familiar with alloc_buffer and
there is quite some tweaking around __GFP_NORETRY in alloc_buffer_data
which I do not follow but GFP_KERNEL just struck my eyes. So why cannot
we have
alloc_buffer(GFP_NOWAIT | __GFP_NOMEMALLOC | __GFP_NOWARN);
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2020-06-25 12:40 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-25 11:31 [PATCH 0/6] Overhaul memalloc_no* Matthew Wilcox (Oracle)
2020-06-25 11:31 ` [PATCH 1/6] mm: Replace PF_MEMALLOC_NOIO with memalloc_noio Matthew Wilcox (Oracle)
2020-06-25 12:22 ` Michal Hocko
2020-06-25 12:34 ` Matthew Wilcox
2020-06-25 12:42 ` Michal Hocko
2020-06-25 11:31 ` [PATCH 2/6] mm: Add become_kswapd and restore_kswapd Matthew Wilcox (Oracle)
2020-06-25 12:31 ` Michal Hocko
2020-06-25 11:31 ` [PATCH 3/6] xfs: Convert to memalloc_nofs_save Matthew Wilcox (Oracle)
2020-06-25 11:31 ` [PATCH 4/6] mm: Replace PF_MEMALLOC_NOFS with memalloc_nofs Matthew Wilcox (Oracle)
2020-06-25 13:35 ` Michal Hocko
2020-06-25 11:31 ` [PATCH 5/6] mm: Replace PF_MEMALLOC_NOIO with memalloc_nocma Matthew Wilcox (Oracle)
2020-06-25 11:31 ` [PATCH 6/6] mm: Add memalloc_nowait Matthew Wilcox (Oracle)
2020-06-25 12:40 ` Michal Hocko [this message]
2020-06-25 13:10 ` Matthew Wilcox
2020-06-25 13:34 ` Michal Hocko
2020-06-25 19:05 ` kernel test robot
2020-06-25 23:51 ` kernel test robot
2020-06-29 5:08 ` Mike Rapoport
2020-06-29 12:18 ` Matthew Wilcox
2020-06-29 12:52 ` Michal Hocko
2020-06-29 13:45 ` Mike Rapoport
2020-06-29 21:28 ` Matthew Wilcox
2020-06-30 6:34 ` Michal Hocko
2020-07-01 4:12 ` Matthew Wilcox
2020-07-01 5:53 ` Michal Hocko
2020-07-01 7:04 ` Mike Rapoport
2020-09-24 0:39 ` Mike Snitzer
2020-09-24 1:10 ` Matthew Wilcox
2020-10-23 14:49 ` Daniel Vetter
2020-06-25 18:48 ` [PATCH 0/6] Overhaul memalloc_no* Darrick J. Wong
2020-06-25 20:34 ` Matthew Wilcox
2020-06-25 20:36 ` Michal Hocko
2020-06-25 20:40 ` Matthew Wilcox
2020-06-26 15:02 ` Mikulas Patocka
2020-06-26 23:08 ` Dave Chinner
2020-06-27 13:09 ` Mikulas Patocka
2020-06-29 0:35 ` Dave Chinner
2020-06-29 13:43 ` Mikulas Patocka
2020-06-29 22:34 ` Dave Chinner
2020-07-03 14:26 ` [PATCH] dm-bufio: do cleanup from a workqueue Mikulas Patocka
2020-06-29 8:22 ` [PATCH 0/6] Overhaul memalloc_no* Michal Hocko
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