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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DF977C4332F for ; Thu, 14 Oct 2021 19:16:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CB02861156 for ; Thu, 14 Oct 2021 19:16:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233440AbhJNTSr (ORCPT ); Thu, 14 Oct 2021 15:18:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49614 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233477AbhJNTSg (ORCPT ); Thu, 14 Oct 2021 15:18:36 -0400 Received: from mail-pg1-x536.google.com (mail-pg1-x536.google.com [IPv6:2607:f8b0:4864:20::536]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E7A7BC061755; Thu, 14 Oct 2021 12:16:30 -0700 (PDT) Received: by mail-pg1-x536.google.com with SMTP id 133so6443240pgb.1; Thu, 14 Oct 2021 12:16:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=MT2VyhwVPZMlSykeLgQd12alBWvS20j5jxYoTfBmcF8=; b=qFnstvGFAe11+1N+bn66uD3hNPdSSlpucyErJYWQmrli/uHhgv+0zU1wnoE9hIuZWW pHZGZKYeAB94W3hp1t6X59GkEgLqpJMlbwIbocWNGlm5wqU88A0CdRaf3YZL10SMxnmV w0vcCOF/B2I6Nabvo1MINSenc9TTmPAnVczGTRGsscNiA1fXQSQhdyya7/lVrRT4Pl2C myzDuHkHzTIp80UXs8YcSNvuGrnMNFQGTAvLh2rOHA0jusiVJJAxFUxrVU7EeERKeCDm HKUY1O0nuUK1ZltJjHfzEHN7MjsegfVRsOUDKra5KqJQ7U2P84DgWCi3WuIJx1jHs3wS yYyA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=MT2VyhwVPZMlSykeLgQd12alBWvS20j5jxYoTfBmcF8=; b=H7RiJ7OvPMek+1/i6PUpJe/ph+v9Ul80oTIh+eMY94iKJ3n43nIUj4bAxFo/Lu53kh 0S7ntbnqYOk93JHeBSMTlhj2kHJjwiLMOKkgw//UlKWmpL1zmJ9rp6ZXeu6wr9HYsSCr DxUhews7vt6fs+zbQKJl+1Ae/QwXiqQl6nWM/7FGKqlWEeemf7DdCr2SLVbnfIZhdggQ 6ww+bdmBkRXuiSH2r3tsQmclyHLMYkXIzyzpCEXOVnQoWC9GTbQiNHcBmUU0evwvqCYM rvpIVdozNJLU9iZOrYKdY2GZ9RbNMxuAlRvIGt6GmVG5nNwRRRYNbC7cKwQE0VSF4ZIO xXKw== X-Gm-Message-State: AOAM53277zbDABVm/+sie9ZlBcxi0aNr7Q7DPA1cbvEAkN+NcZPEiWf6 H3b4FxJAYuCrDGdCnH7X1Zo= X-Google-Smtp-Source: ABdhPJyTvk+9EuoEqGKW2x4LPDHKDtEGLc6hK3T7WNa6tagJM1xlywb9F6NYzZuj4Dz1FPsIQjZeXg== X-Received: by 2002:a05:6a00:1901:b0:44b:e041:f07f with SMTP id y1-20020a056a00190100b0044be041f07fmr7172477pfi.52.1634238990422; Thu, 14 Oct 2021 12:16:30 -0700 (PDT) Received: from localhost.localdomain (c-73-93-239-127.hsd1.ca.comcast.net. [73.93.239.127]) by smtp.gmail.com with ESMTPSA id x129sm3253922pfc.140.2021.10.14.12.16.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 14 Oct 2021 12:16:29 -0700 (PDT) From: Yang Shi To: naoya.horiguchi@nec.com, hughd@google.com, kirill.shutemov@linux.intel.com, willy@infradead.org, peterx@redhat.com, osalvador@suse.de, akpm@linux-foundation.org Cc: shy828301@gmail.com, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [v4 PATCH 4/6] mm: hwpoison: refactor refcount check handling Date: Thu, 14 Oct 2021 12:16:13 -0700 Message-Id: <20211014191615.6674-5-shy828301@gmail.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20211014191615.6674-1-shy828301@gmail.com> References: <20211014191615.6674-1-shy828301@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Memory failure will report failure if the page still has extra pinned refcount other than from hwpoison after the handler is done. Actually the check is not necessary for all handlers, so move the check into specific handlers. This would make the following keeping shmem page in page cache patch easier. There may be expected extra pin for some cases, for example, when the page is dirty and in swapcache. Suggested-by: Naoya Horiguchi Signed-off-by: Naoya Horiguchi Signed-off-by: Yang Shi --- mm/memory-failure.c | 93 +++++++++++++++++++++++++++++++-------------- 1 file changed, 64 insertions(+), 29 deletions(-) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 2809d12f16af..cdf8ccd0865f 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -806,12 +806,44 @@ static int truncate_error_page(struct page *p, unsigned long pfn, return ret; } +struct page_state { + unsigned long mask; + unsigned long res; + enum mf_action_page_type type; + + /* Callback ->action() has to unlock the relevant page inside it. */ + int (*action)(struct page_state *ps, struct page *p); +}; + +/* + * Return true if page is still referenced by others, otherwise return + * false. + * + * The extra_pins is true when one extra refcount is expected. + */ +static bool has_extra_refcount(struct page_state *ps, struct page *p, + bool extra_pins) +{ + int count = page_count(p) - 1; + + if (extra_pins) + count -= 1; + + if (count > 0) { + pr_err("Memory failure: %#lx: %s still referenced by %d users\n", + page_to_pfn(p), action_page_types[ps->type], count); + return true; + } + + return false; +} + /* * Error hit kernel page. * Do nothing, try to be lucky and not touch this instead. For a few cases we * could be more sophisticated. */ -static int me_kernel(struct page *p, unsigned long pfn) +static int me_kernel(struct page_state *ps, struct page *p) { unlock_page(p); return MF_IGNORED; @@ -820,9 +852,9 @@ static int me_kernel(struct page *p, unsigned long pfn) /* * Page in unknown state. Do nothing. */ -static int me_unknown(struct page *p, unsigned long pfn) +static int me_unknown(struct page_state *ps, struct page *p) { - pr_err("Memory failure: %#lx: Unknown page state\n", pfn); + pr_err("Memory failure: %#lx: Unknown page state\n", page_to_pfn(p)); unlock_page(p); return MF_FAILED; } @@ -830,7 +862,7 @@ static int me_unknown(struct page *p, unsigned long pfn) /* * Clean (or cleaned) page cache page. */ -static int me_pagecache_clean(struct page *p, unsigned long pfn) +static int me_pagecache_clean(struct page_state *ps, struct page *p) { int ret; struct address_space *mapping; @@ -867,9 +899,13 @@ static int me_pagecache_clean(struct page *p, unsigned long pfn) * * Open: to take i_rwsem or not for this? Right now we don't. */ - ret = truncate_error_page(p, pfn, mapping); + ret = truncate_error_page(p, page_to_pfn(p), mapping); out: unlock_page(p); + + if (has_extra_refcount(ps, p, false)) + ret = MF_FAILED; + return ret; } @@ -878,7 +914,7 @@ static int me_pagecache_clean(struct page *p, unsigned long pfn) * Issues: when the error hit a hole page the error is not properly * propagated. */ -static int me_pagecache_dirty(struct page *p, unsigned long pfn) +static int me_pagecache_dirty(struct page_state *ps, struct page *p) { struct address_space *mapping = page_mapping(p); @@ -922,7 +958,7 @@ static int me_pagecache_dirty(struct page *p, unsigned long pfn) mapping_set_error(mapping, -EIO); } - return me_pagecache_clean(p, pfn); + return me_pagecache_clean(ps, p); } /* @@ -944,9 +980,10 @@ static int me_pagecache_dirty(struct page *p, unsigned long pfn) * Clean swap cache pages can be directly isolated. A later page fault will * bring in the known good data from disk. */ -static int me_swapcache_dirty(struct page *p, unsigned long pfn) +static int me_swapcache_dirty(struct page_state *ps, struct page *p) { int ret; + bool extra_pins = false; ClearPageDirty(p); /* Trigger EIO in shmem: */ @@ -954,10 +991,17 @@ static int me_swapcache_dirty(struct page *p, unsigned long pfn) ret = delete_from_lru_cache(p) ? MF_FAILED : MF_DELAYED; unlock_page(p); + + if (ret == MF_DELAYED) + extra_pins = true; + + if (has_extra_refcount(ps, p, extra_pins)) + ret = MF_FAILED; + return ret; } -static int me_swapcache_clean(struct page *p, unsigned long pfn) +static int me_swapcache_clean(struct page_state *ps, struct page *p) { int ret; @@ -965,6 +1009,10 @@ static int me_swapcache_clean(struct page *p, unsigned long pfn) ret = delete_from_lru_cache(p) ? MF_FAILED : MF_RECOVERED; unlock_page(p); + + if (has_extra_refcount(ps, p, false)) + ret = MF_FAILED; + return ret; } @@ -974,7 +1022,7 @@ static int me_swapcache_clean(struct page *p, unsigned long pfn) * - Error on hugepage is contained in hugepage unit (not in raw page unit.) * To narrow down kill region to one page, we need to break up pmd. */ -static int me_huge_page(struct page *p, unsigned long pfn) +static int me_huge_page(struct page_state *ps, struct page *p) { int res; struct page *hpage = compound_head(p); @@ -985,7 +1033,7 @@ static int me_huge_page(struct page *p, unsigned long pfn) mapping = page_mapping(hpage); if (mapping) { - res = truncate_error_page(hpage, pfn, mapping); + res = truncate_error_page(hpage, page_to_pfn(p), mapping); unlock_page(hpage); } else { res = MF_FAILED; @@ -1003,6 +1051,9 @@ static int me_huge_page(struct page *p, unsigned long pfn) } } + if (has_extra_refcount(ps, p, false)) + res = MF_FAILED; + return res; } @@ -1028,14 +1079,7 @@ static int me_huge_page(struct page *p, unsigned long pfn) #define slab (1UL << PG_slab) #define reserved (1UL << PG_reserved) -static struct page_state { - unsigned long mask; - unsigned long res; - enum mf_action_page_type type; - - /* Callback ->action() has to unlock the relevant page inside it. */ - int (*action)(struct page *p, unsigned long pfn); -} error_states[] = { +static struct page_state error_states[] = { { reserved, reserved, MF_MSG_KERNEL, me_kernel }, /* * free pages are specially detected outside this table: @@ -1095,19 +1139,10 @@ static int page_action(struct page_state *ps, struct page *p, unsigned long pfn) { int result; - int count; /* page p should be unlocked after returning from ps->action(). */ - result = ps->action(p, pfn); + result = ps->action(ps, p); - count = page_count(p) - 1; - if (ps->action == me_swapcache_dirty && result == MF_DELAYED) - count--; - if (count > 0) { - pr_err("Memory failure: %#lx: %s still referenced by %d users\n", - pfn, action_page_types[ps->type], count); - result = MF_FAILED; - } action_result(pfn, ps->type, result); /* Could do more checks here if page looks ok */ -- 2.26.2