From: "Matthew Wilcox (Oracle)" <willy@infradead.org> To: linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: "Matthew Wilcox (Oracle)" <willy@infradead.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: [PATCH 6/6] mm: Add memalloc_nowait Date: Thu, 25 Jun 2020 12:31:22 +0100 [thread overview] Message-ID: <20200625113122.7540-7-willy@infradead.org> (raw) In-Reply-To: <20200625113122.7540-1-willy@infradead.org> 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. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> --- drivers/md/dm-bufio.c | 30 ++++++++---------------------- include/linux/sched.h | 1 + include/linux/sched/mm.h | 12 ++++++++---- 3 files changed, 17 insertions(+), 26 deletions(-) diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c index 6d1565021d74..140ada9a2c8f 100644 --- a/drivers/md/dm-bufio.c +++ b/drivers/md/dm-bufio.c @@ -412,23 +412,6 @@ static void *alloc_buffer_data(struct dm_bufio_client *c, gfp_t gfp_mask, *data_mode = DATA_MODE_VMALLOC; - /* - * __vmalloc allocates the data pages and auxiliary structures with - * gfp_flags that were specified, but pagetables are always allocated - * with GFP_KERNEL, no matter what was specified as gfp_mask. - * - * Consequently, we must set per-process flag PF_MEMALLOC_NOIO so that - * all allocations done by this process (including pagetables) are done - * as if GFP_NOIO was specified. - */ - if (gfp_mask & __GFP_NORETRY) { - unsigned noio_flag = memalloc_noio_save(); - void *ptr = __vmalloc(c->block_size, gfp_mask); - - memalloc_noio_restore(noio_flag); - return ptr; - } - return __vmalloc(c->block_size, gfp_mask); } @@ -866,9 +849,6 @@ static struct dm_buffer *__alloc_buffer_wait_no_callback(struct dm_bufio_client * dm-bufio is resistant to allocation failures (it just keeps * one buffer reserved in cases all the allocations fail). * So set flags to not try too hard: - * GFP_NOWAIT: don't wait; if we need to sleep we'll release our - * mutex and wait ourselves. - * __GFP_NORETRY: don't retry and rather return failure * __GFP_NOMEMALLOC: don't use emergency reserves * __GFP_NOWARN: don't print a warning in case of failure * @@ -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); if (b) return b; } @@ -886,8 +868,12 @@ static struct dm_buffer *__alloc_buffer_wait_no_callback(struct dm_bufio_client return NULL; if (dm_bufio_cache_size_latch != 1 && !tried_noio_alloc) { + unsigned noio_flag; + dm_bufio_unlock(c); - b = alloc_buffer(c, GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN); + noio_flag = memalloc_noio_save(); + b = alloc_buffer(c, GFP_KERNEL | __GFP_NOMEMALLOC | __GFP_NOWARN); + memalloc_noio_restore(noio_flag); dm_bufio_lock(c); if (b) return b; diff --git a/include/linux/sched.h b/include/linux/sched.h index 90336850e940..b1c2cddd366c 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -803,6 +803,7 @@ struct task_struct { #endif unsigned memalloc_noio:1; unsigned memalloc_nofs:1; + unsigned memalloc_nowait:1; unsigned memalloc_nocma:1; unsigned long atomic_flags; /* Flags requiring atomic access. */ diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h index 6f7b59a848a6..6484569f50df 100644 --- a/include/linux/sched/mm.h +++ b/include/linux/sched/mm.h @@ -179,12 +179,16 @@ static inline bool in_vfork(struct task_struct *tsk) static inline gfp_t current_gfp_context(gfp_t flags) { if (unlikely(current->memalloc_noio || current->memalloc_nofs || - current->memalloc_nocma)) { + current->memalloc_nocma) || current->memalloc_nowait) { /* - * NOIO implies both NOIO and NOFS and it is a weaker context - * so always make sure it makes precedence + * Clearing DIRECT_RECLAIM means we won't get to the point + * of testing IO or FS, so we don't need to bother clearing + * them. noio implies neither IO nor FS and it is a weaker + * context so always make sure it takes precedence. */ - if (current->memalloc_noio) + if (current->memalloc_nowait) + flags &= ~__GFP_DIRECT_RECLAIM; + else if (current->memalloc_noio) flags &= ~(__GFP_IO | __GFP_FS); else if (current->memalloc_nofs) flags &= ~__GFP_FS; -- 2.27.0
next prev parent reply other threads:[~2020-06-25 11:31 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 ` Matthew Wilcox (Oracle) [this message] 2020-06-25 12:40 ` [PATCH 6/6] mm: Add memalloc_nowait Michal Hocko 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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