From e9237a20fea5f164481fcab3ff286f4e1da74550 Mon Sep 17 00:00:00 2001 From: Edward Wu Date: Thu, 16 Jun 2022 07:34:20 +0800 Subject: SPL-14059 mm: cma: sync everything after EBUSY Since file-backed memory on CMA area could take long-term pinning. By Minchan Kim's debug commit 151e084af494 ("mm: page_alloc: dump migrate-failed pages only at -EBUSY") We know the pinned page comes from buffer_head, ext4 journal, FS metadata. Sync everything after EBUSY that can unpin most file-system pages. And raise the success rate at next time try. Link: https://lkml.kernel.org/r/20220615021504.23358-1-edwardwu@realtek.com Signed-off-by: Edward Wu --- mm/cma.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/mm/cma.c b/mm/cma.c index 30b6ca30009b..3ebf66d6d597 100644 --- a/mm/cma.c +++ b/mm/cma.c @@ -31,6 +31,7 @@ #include #include #include +#include #include #include "cma.h" @@ -411,6 +412,24 @@ static void cma_debug_show_areas(struct cma *cma) static inline void cma_debug_show_areas(struct cma *cma) { } #endif +static void cma_sync_work(struct work_struct *work) +{ + ksys_sync(); + kfree(work); + pr_debug("%s(): EBUSY Sync complete\n", __func__); +} + +static void cma_ebusy_sync_pinned_pages(void) +{ + struct work_struct *work; + + work = kmalloc(sizeof(*work), GFP_ATOMIC); + if (work) { + INIT_WORK(work, cma_sync_work); + schedule_work(work); + } +} + /** * cma_alloc() - allocate pages from contiguous area * @cma: Contiguous memory region for which the allocation is performed. @@ -431,6 +450,7 @@ struct page *cma_alloc(struct cma *cma, unsigned long count, unsigned long i; struct page *page = NULL; int ret = -ENOMEM; + bool sys_synchronized = false; if (!cma || !cma->count || !cma->bitmap) goto out; @@ -482,6 +502,11 @@ struct page *cma_alloc(struct cma *cma, unsigned long count, if (ret != -EBUSY) break; + if (!sys_synchronized) { + sys_synchronized = true; + cma_ebusy_sync_pinned_pages(); + } + pr_debug("%s(): memory range at %p is busy, retrying\n", __func__, pfn_to_page(pfn)); -- cgit v1.2.3