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Date: Mon, 29 Jan 2024 20:36:43 -0500
From: Johannes Weiner <hannes@...xchg.org>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Nhat Pham <nphamcs@...il.com>,
Yosry Ahmed <yosryahmed@...gle.com>,
Chengming Zhou <zhouchengming@...edance.com>,
linux-mm@...ck.org,
linux-kernel@...r.kernel.org
Subject: [PATCH 07/20] mm: zswap: break out zwap_compress()
zswap_store() is long and mixes work at the zswap layer with work at
the backend and compression layer. Move compression & backend work to
zswap_compress(), mirroring zswap_decompress().
Signed-off-by: Johannes Weiner <hannes@...xchg.org>
---
mm/zswap.c | 145 ++++++++++++++++++++++++++++-------------------------
1 file changed, 77 insertions(+), 68 deletions(-)
diff --git a/mm/zswap.c b/mm/zswap.c
index bdc9f82fe4b9..f9b9494156ba 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -1316,6 +1316,79 @@ static int zswap_enabled_param_set(const char *val,
return ret;
}
+static bool zswap_compress(struct folio *folio, struct zswap_entry *entry)
+{
+ struct crypto_acomp_ctx *acomp_ctx;
+ struct scatterlist input, output;
+ unsigned int dlen = PAGE_SIZE;
+ unsigned long handle;
+ struct zpool *zpool;
+ char *buf;
+ gfp_t gfp;
+ int ret;
+ u8 *dst;
+
+ acomp_ctx = raw_cpu_ptr(entry->pool->acomp_ctx);
+
+ mutex_lock(&acomp_ctx->mutex);
+
+ dst = acomp_ctx->buffer;
+ sg_init_table(&input, 1);
+ sg_set_page(&input, &folio->page, PAGE_SIZE, 0);
+
+ /*
+ * We need PAGE_SIZE * 2 here since there maybe over-compression case,
+ * and hardware-accelerators may won't check the dst buffer size, so
+ * giving the dst buffer with enough length to avoid buffer overflow.
+ */
+ sg_init_one(&output, dst, PAGE_SIZE * 2);
+ acomp_request_set_params(acomp_ctx->req, &input, &output, PAGE_SIZE, dlen);
+
+ /*
+ * it maybe looks a little bit silly that we send an asynchronous request,
+ * then wait for its completion synchronously. This makes the process look
+ * synchronous in fact.
+ * Theoretically, acomp supports users send multiple acomp requests in one
+ * acomp instance, then get those requests done simultaneously. but in this
+ * case, zswap actually does store and load page by page, there is no
+ * existing method to send the second page before the first page is done
+ * in one thread doing zwap.
+ * but in different threads running on different cpu, we have different
+ * acomp instance, so multiple threads can do (de)compression in parallel.
+ */
+ ret = crypto_wait_req(crypto_acomp_compress(acomp_ctx->req), &acomp_ctx->wait);
+ dlen = acomp_ctx->req->dlen;
+ if (ret) {
+ zswap_reject_compress_fail++;
+ goto unlock;
+ }
+
+ zpool = zswap_find_zpool(entry);
+ gfp = __GFP_NORETRY | __GFP_NOWARN | __GFP_KSWAPD_RECLAIM;
+ if (zpool_malloc_support_movable(zpool))
+ gfp |= __GFP_HIGHMEM | __GFP_MOVABLE;
+ ret = zpool_malloc(zpool, dlen, gfp, &handle);
+ if (ret == -ENOSPC) {
+ zswap_reject_compress_poor++;
+ goto unlock;
+ }
+ if (ret) {
+ zswap_reject_alloc_fail++;
+ goto unlock;
+ }
+
+ buf = zpool_map_handle(zpool, handle, ZPOOL_MM_WO);
+ memcpy(buf, dst, dlen);
+ zpool_unmap_handle(zpool, handle);
+
+ entry->handle = handle;
+ entry->length = dlen;
+
+unlock:
+ mutex_unlock(&acomp_ctx->mutex);
+ return ret == 0;
+}
+
static void zswap_decompress(struct zswap_entry *entry, struct page *page)
{
struct zpool *zpool = zswap_find_zpool(entry);
@@ -1472,18 +1545,11 @@ bool zswap_store(struct folio *folio)
struct page *page = &folio->page;
struct zswap_tree *tree = swap_zswap_tree(swp);
struct zswap_entry *entry, *dupentry;
- struct scatterlist input, output;
- struct crypto_acomp_ctx *acomp_ctx;
struct obj_cgroup *objcg = NULL;
struct mem_cgroup *memcg = NULL;
struct zswap_pool *pool;
- struct zpool *zpool;
- unsigned int dlen = PAGE_SIZE;
- unsigned long handle, value;
- char *buf;
- u8 *src, *dst;
- gfp_t gfp;
- int ret;
+ unsigned long value;
+ u8 *src;
VM_WARN_ON_ONCE(!folio_test_locked(folio));
VM_WARN_ON_ONCE(!folio_test_swapcache(folio));
@@ -1568,65 +1634,10 @@ bool zswap_store(struct folio *folio)
mem_cgroup_put(memcg);
}
- /* compress */
- acomp_ctx = raw_cpu_ptr(entry->pool->acomp_ctx);
-
- mutex_lock(&acomp_ctx->mutex);
-
- dst = acomp_ctx->buffer;
- sg_init_table(&input, 1);
- sg_set_page(&input, &folio->page, PAGE_SIZE, 0);
+ if (!zswap_compress(folio, entry))
+ goto put_pool;
- /*
- * We need PAGE_SIZE * 2 here since there maybe over-compression case,
- * and hardware-accelerators may won't check the dst buffer size, so
- * giving the dst buffer with enough length to avoid buffer overflow.
- */
- sg_init_one(&output, dst, PAGE_SIZE * 2);
- acomp_request_set_params(acomp_ctx->req, &input, &output, PAGE_SIZE, dlen);
- /*
- * it maybe looks a little bit silly that we send an asynchronous request,
- * then wait for its completion synchronously. This makes the process look
- * synchronous in fact.
- * Theoretically, acomp supports users send multiple acomp requests in one
- * acomp instance, then get those requests done simultaneously. but in this
- * case, zswap actually does store and load page by page, there is no
- * existing method to send the second page before the first page is done
- * in one thread doing zwap.
- * but in different threads running on different cpu, we have different
- * acomp instance, so multiple threads can do (de)compression in parallel.
- */
- ret = crypto_wait_req(crypto_acomp_compress(acomp_ctx->req), &acomp_ctx->wait);
- dlen = acomp_ctx->req->dlen;
-
- if (ret) {
- zswap_reject_compress_fail++;
- goto put_dstmem;
- }
-
- /* store */
- zpool = zswap_find_zpool(entry);
- gfp = __GFP_NORETRY | __GFP_NOWARN | __GFP_KSWAPD_RECLAIM;
- if (zpool_malloc_support_movable(zpool))
- gfp |= __GFP_HIGHMEM | __GFP_MOVABLE;
- ret = zpool_malloc(zpool, dlen, gfp, &handle);
- if (ret == -ENOSPC) {
- zswap_reject_compress_poor++;
- goto put_dstmem;
- }
- if (ret) {
- zswap_reject_alloc_fail++;
- goto put_dstmem;
- }
- buf = zpool_map_handle(zpool, handle, ZPOOL_MM_WO);
- memcpy(buf, dst, dlen);
- zpool_unmap_handle(zpool, handle);
- mutex_unlock(&acomp_ctx->mutex);
-
- /* populate entry */
entry->swpentry = swp;
- entry->handle = handle;
- entry->length = dlen;
insert_entry:
entry->objcg = objcg;
@@ -1663,8 +1674,6 @@ bool zswap_store(struct folio *folio)
return true;
-put_dstmem:
- mutex_unlock(&acomp_ctx->mutex);
put_pool:
zswap_pool_put(entry->pool);
freepage:
--
2.43.0
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