From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6B44EC4332F for ; Thu, 24 Nov 2022 03:44:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229486AbiKXDos (ORCPT ); Wed, 23 Nov 2022 22:44:48 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34682 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229452AbiKXDor (ORCPT ); Wed, 23 Nov 2022 22:44:47 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B3192D1 for ; Wed, 23 Nov 2022 19:44:46 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 4DBC761FC2 for ; Thu, 24 Nov 2022 03:44:46 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A3558C433D6; Thu, 24 Nov 2022 03:44:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1669261485; bh=RfOjGezK7Cg2ZMxZhEt+V4OeSjvegnBDAoF4ylN1Xgw=; h=Date:To:From:Subject:From; b=l+O5A9QD7BYNkz9nvPZ4hIys4FbKzGnCqPMOV5NOplZWuB+4xcOZRF6O9T2/ztsGk XaTeO2HG63qtaUk0QU7Hj4aZi8gwTOZz2BsJlSPgyG73IAaNHIa0+uS2w/+xkZ6+Mw QOGaKsURZju+gJIG7sAOjBw+9AmEX9sL/oPCDjJo= Date: Wed, 23 Nov 2022 19:44:44 -0800 To: mm-commits@vger.kernel.org, vitaly.wool@konsulko.com, sjenning@redhat.com, senozhatsky@chromium.org, nphamcs@gmail.com, ngupta@vflare.org, minchan@kernel.org, ddstreet@ieee.org, hannes@cmpxchg.org, akpm@linux-foundation.org From: Andrew Morton Subject: [to-be-updated] zswap-fix-writeback-lock-ordering-for-zsmalloc.patch removed from -mm tree Message-Id: <20221124034445.A3558C433D6@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The quilt patch titled Subject: zswap: fix writeback lock ordering for zsmalloc has been removed from the -mm tree. Its filename was zswap-fix-writeback-lock-ordering-for-zsmalloc.patch This patch was dropped because an updated version will be merged ------------------------------------------------------ From: Johannes Weiner Subject: zswap: fix writeback lock ordering for zsmalloc Date: Fri, 18 Nov 2022 16:15:31 -0800 Patch series "Implement writeback for zsmalloc", v3. Unlike other zswaps allocators such as zbud or z3fold, zsmalloc currently lacks the writeback mechanism. This means that when the zswap pool is full, it will simply reject further allocations, and the pages will be written directly to swap. This series of patches implements writeback for zsmalloc. When the zswap pool becomes full, zsmalloc will attempt to evict all the compressed objects in the least-recently used zspages. This patch (of 6): zswap's customary lock order is tree->lock before pool->lock, because the tree->lock protects the entries' refcount, and the free callbacks in the backends acquire their respective pool locks to dispatch the backing object. zsmalloc's map callback takes the pool lock, so zswap must not grab the tree->lock while a handle is mapped. This currently only happens during writeback, which isn't implemented for zsmalloc. In preparation for it, move the tree->lock section out of the mapped entry section Link: https://lkml.kernel.org/r/20221119001536.2086599-1-nphamcs@gmail.com Link: https://lkml.kernel.org/r/20221119001536.2086599-2-nphamcs@gmail.com Signed-off-by: Johannes Weiner Signed-off-by: Nhat Pham Cc: Dan Streetman Cc: Minchan Kim Cc: Nitin Gupta Cc: Sergey Senozhatsky Cc: Seth Jennings Cc: Vitaly Wool Signed-off-by: Andrew Morton --- mm/zswap.c | 37 ++++++++++++++++++++----------------- 1 file changed, 20 insertions(+), 17 deletions(-) --- a/mm/zswap.c~zswap-fix-writeback-lock-ordering-for-zsmalloc +++ a/mm/zswap.c @@ -958,7 +958,7 @@ static int zswap_writeback_entry(struct }; if (!zpool_can_sleep_mapped(pool)) { - tmp = kmalloc(PAGE_SIZE, GFP_ATOMIC); + tmp = kmalloc(PAGE_SIZE, GFP_KERNEL); if (!tmp) return -ENOMEM; } @@ -968,6 +968,7 @@ static int zswap_writeback_entry(struct swpentry = zhdr->swpentry; /* here */ tree = zswap_trees[swp_type(swpentry)]; offset = swp_offset(swpentry); + zpool_unmap_handle(pool, handle); /* find and ref zswap entry */ spin_lock(&tree->lock); @@ -975,20 +976,12 @@ static int zswap_writeback_entry(struct if (!entry) { /* entry was invalidated */ spin_unlock(&tree->lock); - zpool_unmap_handle(pool, handle); kfree(tmp); return 0; } spin_unlock(&tree->lock); BUG_ON(offset != entry->offset); - src = (u8 *)zhdr + sizeof(struct zswap_header); - if (!zpool_can_sleep_mapped(pool)) { - memcpy(tmp, src, entry->length); - src = tmp; - zpool_unmap_handle(pool, handle); - } - /* try to allocate swap cache page */ switch (zswap_get_swap_cache_page(swpentry, &page)) { case ZSWAP_SWAPCACHE_FAIL: /* no memory or invalidate happened */ @@ -1006,6 +999,14 @@ static int zswap_writeback_entry(struct acomp_ctx = raw_cpu_ptr(entry->pool->acomp_ctx); dlen = PAGE_SIZE; + zhdr = zpool_map_handle(pool, handle, ZPOOL_MM_RO); + src = (u8 *)zhdr + sizeof(struct zswap_header); + if (!zpool_can_sleep_mapped(pool)) { + memcpy(tmp, src, entry->length); + src = tmp; + zpool_unmap_handle(pool, handle); + } + mutex_lock(acomp_ctx->mutex); sg_init_one(&input, src, entry->length); sg_init_table(&output, 1); @@ -1015,6 +1016,11 @@ static int zswap_writeback_entry(struct dlen = acomp_ctx->req->dlen; mutex_unlock(acomp_ctx->mutex); + if (!zpool_can_sleep_mapped(pool)) + kfree(tmp); + else + zpool_unmap_handle(pool, handle); + BUG_ON(ret); BUG_ON(dlen != PAGE_SIZE); @@ -1045,7 +1051,11 @@ static int zswap_writeback_entry(struct zswap_entry_put(tree, entry); spin_unlock(&tree->lock); - goto end; + return ret; + +fail: + if (!zpool_can_sleep_mapped(pool)) + kfree(tmp); /* * if we get here due to ZSWAP_SWAPCACHE_EXIST @@ -1054,17 +1064,10 @@ static int zswap_writeback_entry(struct * if we free the entry in the following put * it is also okay to return !0 */ -fail: spin_lock(&tree->lock); zswap_entry_put(tree, entry); spin_unlock(&tree->lock); -end: - if (zpool_can_sleep_mapped(pool)) - zpool_unmap_handle(pool, handle); - else - kfree(tmp); - return ret; } _ Patches currently in -mm which might be from hannes@cmpxchg.org are mm-vmscan-split-khugepaged-stats-from-direct-reclaim-stats.patch zpool-clean-out-dead-code.patch mm-remove-lock_page_memcg-from-rmap.patch