[PATCH v4 02/25] md/md-llbitmap: use GFP_NOIO for cache allocations
From: Yu Kuai <yukuai@kernel.org>
Date: 2026-08-01 17:25:52
Also in:
lkml
Subsystem:
software raid (multiple disks) support, the rest · Maintainers:
Song Liu, Yu Kuai, Linus Torvalds
From: Yu Kuai <yukuai@fygo.io> llbitmap allocates its in-memory page cache and page-control structures from paths that can already be holding MD reconfiguration or bitmap state locks. For example, component_size_store() takes mddev_lock(), update_size() calls the personality resize method, and llbitmap_resize() can grow the page cache through llbitmap_prepare_resize(). Using GFP_KERNEL in those paths allows direct reclaim to enter filesystem or block I/O while MD resize state is locked. That can recurse back into the same array and wait on state that cannot make progress until the resize path finishes. Use GFP_NOIO for the llbitmap object, cached bitmap pages, page controls, page-control arrays, and percpu_ref initialization. Leave the explicit metadata zeroout path unchanged because it is intentional bitmap I/O rather than reclaim-driven allocation. Signed-off-by: Yu Kuai <yukuai@fygo.io> --- drivers/md/md-llbitmap.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/md/md-llbitmap.c b/drivers/md/md-llbitmap.c
index 131582724e7e..6ab2188bba27 100644
--- a/drivers/md/md-llbitmap.c
+++ b/drivers/md/md-llbitmap.c@@ -521,7 +521,7 @@ static struct page *llbitmap_read_page(struct llbitmap *llbitmap, int idx) if (page) return page; - page = alloc_page(GFP_KERNEL | __GFP_ZERO); + page = alloc_page(GFP_NOIO | __GFP_ZERO); if (!page) return ERR_PTR(-ENOMEM);
@@ -616,12 +616,12 @@ static int llbitmap_cache_pages(struct llbitmap *llbitmap) int i; llbitmap->pctl = kmalloc_array(nr_pages, sizeof(void *), - GFP_KERNEL | __GFP_ZERO); + GFP_NOIO | __GFP_ZERO); if (!llbitmap->pctl) return -ENOMEM; size = round_up(size, cache_line_size()); - pctl = kmalloc_array(nr_pages, size, GFP_KERNEL | __GFP_ZERO); + pctl = kmalloc_array(nr_pages, size, GFP_NOIO | __GFP_ZERO); if (!pctl) { kfree(llbitmap->pctl); return -ENOMEM;
@@ -640,7 +640,7 @@ static int llbitmap_cache_pages(struct llbitmap *llbitmap) } if (percpu_ref_init(&pctl->active, active_release, - PERCPU_REF_ALLOW_REINIT, GFP_KERNEL)) { + PERCPU_REF_ALLOW_REINIT, GFP_NOIO)) { __free_page(page); llbitmap_free_pages(llbitmap); return -ENOMEM;
@@ -1110,7 +1110,7 @@ static int llbitmap_create(struct mddev *mddev) if (ret) return ret; - llbitmap = kzalloc_obj(*llbitmap); + llbitmap = kzalloc_obj(*llbitmap, GFP_NOIO); if (!llbitmap) return -ENOMEM;
--
2.51.0