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author | Chunhai Guo <guochunhai@vivo.com> | 2024-04-02 04:00:36 -0600 |
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committer | Gao Xiang <hsiangkao@linux.alibaba.com> | 2024-05-08 17:12:49 +0800 |
commit | f36f3010f67611a45d66e773bc91e4c66a9abab5 (patch) | |
tree | 8eea1fa6dd42d314a15641fd422f7998cad69a05 /fs/erofs/pcpubuf.c | |
parent | cacd5b04e24c74a813c694ec7b26a1a370b5d666 (diff) | |
download | linux-f36f3010f67611a45d66e773bc91e4c66a9abab5.tar.gz linux-f36f3010f67611a45d66e773bc91e4c66a9abab5.tar.bz2 linux-f36f3010f67611a45d66e773bc91e4c66a9abab5.zip |
erofs: rename per-CPU buffers to global buffer pool and make it configurable
It will cost more time if compressed buffers are allocated on demand for
low-latency algorithms (like lz4) so EROFS uses per-CPU buffers to keep
compressed data if in-place decompression is unfulfilled. While it is kind
of wasteful of memory for a device with hundreds of CPUs, and only a small
number of CPUs concurrently decompress most of the time.
This patch renames it as 'global buffer pool' and makes it configurable.
This allows two or more CPUs to share a common buffer to reduce memory
occupation.
Suggested-by: Gao Xiang <xiang@kernel.org>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Chunhai Guo <guochunhai@vivo.com>
Link: https://lore.kernel.org/r/20240402100036.2673604-1-guochunhai@vivo.com
Signed-off-by: Sandeep Dhavale <dhavale@google.com>
Link: https://lore.kernel.org/r/20240408215231.3376659-1-dhavale@google.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Diffstat (limited to 'fs/erofs/pcpubuf.c')
-rw-r--r-- | fs/erofs/pcpubuf.c | 148 |
1 files changed, 0 insertions, 148 deletions
diff --git a/fs/erofs/pcpubuf.c b/fs/erofs/pcpubuf.c deleted file mode 100644 index c7a4b1d77069..000000000000 --- a/fs/erofs/pcpubuf.c +++ /dev/null @@ -1,148 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0-only -/* - * Copyright (C) Gao Xiang <xiang@kernel.org> - * - * For low-latency decompression algorithms (e.g. lz4), reserve consecutive - * per-CPU virtual memory (in pages) in advance to store such inplace I/O - * data if inplace decompression is failed (due to unmet inplace margin for - * example). - */ -#include "internal.h" - -struct erofs_pcpubuf { - raw_spinlock_t lock; - void *ptr; - struct page **pages; - unsigned int nrpages; -}; - -static DEFINE_PER_CPU(struct erofs_pcpubuf, erofs_pcb); - -void *erofs_get_pcpubuf(unsigned int requiredpages) - __acquires(pcb->lock) -{ - struct erofs_pcpubuf *pcb = &get_cpu_var(erofs_pcb); - - raw_spin_lock(&pcb->lock); - /* check if the per-CPU buffer is too small */ - if (requiredpages > pcb->nrpages) { - raw_spin_unlock(&pcb->lock); - put_cpu_var(erofs_pcb); - /* (for sparse checker) pretend pcb->lock is still taken */ - __acquire(pcb->lock); - return NULL; - } - return pcb->ptr; -} - -void erofs_put_pcpubuf(void *ptr) __releases(pcb->lock) -{ - struct erofs_pcpubuf *pcb = &per_cpu(erofs_pcb, smp_processor_id()); - - DBG_BUGON(pcb->ptr != ptr); - raw_spin_unlock(&pcb->lock); - put_cpu_var(erofs_pcb); -} - -/* the next step: support per-CPU page buffers hotplug */ -int erofs_pcpubuf_growsize(unsigned int nrpages) -{ - static DEFINE_MUTEX(pcb_resize_mutex); - static unsigned int pcb_nrpages; - struct page *pagepool = NULL; - int delta, cpu, ret, i; - - mutex_lock(&pcb_resize_mutex); - delta = nrpages - pcb_nrpages; - ret = 0; - /* avoid shrinking pcpubuf, since no idea how many fses rely on */ - if (delta <= 0) - goto out; - - for_each_possible_cpu(cpu) { - struct erofs_pcpubuf *pcb = &per_cpu(erofs_pcb, cpu); - struct page **pages, **oldpages; - void *ptr, *old_ptr; - - pages = kmalloc_array(nrpages, sizeof(*pages), GFP_KERNEL); - if (!pages) { - ret = -ENOMEM; - break; - } - - for (i = 0; i < nrpages; ++i) { - pages[i] = erofs_allocpage(&pagepool, GFP_KERNEL); - if (!pages[i]) { - ret = -ENOMEM; - oldpages = pages; - goto free_pagearray; - } - } - ptr = vmap(pages, nrpages, VM_MAP, PAGE_KERNEL); - if (!ptr) { - ret = -ENOMEM; - oldpages = pages; - goto free_pagearray; - } - raw_spin_lock(&pcb->lock); - old_ptr = pcb->ptr; - pcb->ptr = ptr; - oldpages = pcb->pages; - pcb->pages = pages; - i = pcb->nrpages; - pcb->nrpages = nrpages; - raw_spin_unlock(&pcb->lock); - - if (!oldpages) { - DBG_BUGON(old_ptr); - continue; - } - - if (old_ptr) - vunmap(old_ptr); -free_pagearray: - while (i) - erofs_pagepool_add(&pagepool, oldpages[--i]); - kfree(oldpages); - if (ret) - break; - } - pcb_nrpages = nrpages; - erofs_release_pages(&pagepool); -out: - mutex_unlock(&pcb_resize_mutex); - return ret; -} - -void __init erofs_pcpubuf_init(void) -{ - int cpu; - - for_each_possible_cpu(cpu) { - struct erofs_pcpubuf *pcb = &per_cpu(erofs_pcb, cpu); - - raw_spin_lock_init(&pcb->lock); - } -} - -void erofs_pcpubuf_exit(void) -{ - int cpu, i; - - for_each_possible_cpu(cpu) { - struct erofs_pcpubuf *pcb = &per_cpu(erofs_pcb, cpu); - - if (pcb->ptr) { - vunmap(pcb->ptr); - pcb->ptr = NULL; - } - if (!pcb->pages) - continue; - - for (i = 0; i < pcb->nrpages; ++i) - if (pcb->pages[i]) - put_page(pcb->pages[i]); - kfree(pcb->pages); - pcb->pages = NULL; - } -} |