From nobody Mon Feb 9 06:25:36 2026 Received: from mail-yw1-f202.google.com (mail-yw1-f202.google.com [209.85.128.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 93200165EF0 for ; Sun, 11 Aug 2024 21:21:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.202 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723411303; cv=none; b=e42zOwtBmqQbVYMxIu6Pp6AmyKRHBWWLdPFi/5fuqW1UkkGCENs34W3Dsy0b+BhhN/cAkAoSsaAEl2V05QQo7utSqgu1QottFXtUtxf8IKjfwDgUJxHf6bB70lUzB3Qs5SHFiHBeJ3uDAr61A7O1DwYUPH6qyY/S9ipH/BFCvDg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723411303; c=relaxed/simple; bh=rX/uyGK859Qv0c/8SCHhsaXgw8NXAEtdAyPwFlV/th8=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=jmWEarIMxsOyasOq4MDzMvxqbNSIIF+LgNqA1tKbl2yZmlq+MVwSZ8EmXPshpM3jLrnA+m7J9CeuEv4dY38x2uQsx+0R4YK8CA4WorRba4CxMzYRtVU8WSwgtFsu3qelcBT5kOJfNZgBTStM/2J1zhTmS1R7J5R8INPuumtmAZc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--yuzhao.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=E9l63VT9; arc=none smtp.client-ip=209.85.128.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--yuzhao.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="E9l63VT9" Received: by mail-yw1-f202.google.com with SMTP id 00721157ae682-654d96c2bb5so71759517b3.2 for ; Sun, 11 Aug 2024 14:21:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1723411300; x=1724016100; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=plPNUwSc20wvxDLG/5V4ONiycR26+90aEQUlSgRQtvI=; b=E9l63VT9e91/MxKGZp02kE0MK5vH7t4CcV1mPs88z+waj062iJejvzuwInKABnG3Tr WF+nFKZ2C8Ol4x1Y5yOeCUwmrT/12Q6kAzkInAhktCiq0f7/2cSRhb/vZFvjvQzeiYJ7 /1puVbwvEvEa1ndM8w5/IkQO3jnmoM9GDXdHg01lIMBuEnki47ZYdsvoWjQVFFJGvmvt Fgl8NCuyT1RmNSE8O/+Qxtg4onuHc7DXOHnI3XbQP3lftgzC+if2bS8Mj8yzzQ5o8Utg afvwrHpI3OwtT8IiY9UoH5EkTjYI87yOS2gbnoyV2b3j1FEqJkkmumdLMDApWUqPjD9v 6YYw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1723411300; x=1724016100; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=plPNUwSc20wvxDLG/5V4ONiycR26+90aEQUlSgRQtvI=; b=G9oIfwa7GoYFzYn3wTsma+i4XDmg4+OVp0ppMOEabqc1GfZ6gOtphnSYG4OSE6Gdvg xNWi86CW2jJv1IFz20AhfJ6y7RSTOUdHjeoNAwBHDl6H5nVWmqFmWvCzHEMSDfHZIoaw kzxbM6J417EM9xsrQ7K9OQLltOUjCMglkhoqF41+82xwdcddKGuhtab8ICcc1syAcwpg Ddl5uc5AX31UiKW355DyBjYYYK6IAg02v5dPzoCL71a/fH586YEgh0pEews8XaKx68T6 iK+DZ5q1qHJcgahY31wr5rQ9Y1m+dwvyw7TW4bfZDurv/xdbIrtOQ1JRc6gfZcCKTQKC FjOQ== X-Forwarded-Encrypted: i=1; AJvYcCWocmHhUD1WtQb3Vh4dTWiQPGdgfRFXKoCLrVD5OkhSqjuZpug0TuHq3mszZN9lbwC1acsA5D/esUAzdAGnQz6KtDNCh02B7wcSPwgv X-Gm-Message-State: AOJu0YxG3jaSoDaKaGxm3lytAXQRpTGZ+Pw9gU4IjV2Nt2IEun3Xr5fq 0nIBQ+uY/jKlQVRr4y3wDrRM6xdOdZE0LYk3A9whPR7PiJoYuDrQBq0opDxMv9y4EdP1dSmKKy7 nGw== X-Google-Smtp-Source: AGHT+IHabmrGk91oLaByBgnfM+5JbvP9zqcwTHpzXiVoA50OMZR/9U6IX+5qqzgzKEbG6UqMgpxrz3SgVrA= X-Received: from yuzhao2.bld.corp.google.com ([2a00:79e0:2e28:6:c9c:12b4:a1e3:7f10]) (user=yuzhao job=sendgmr) by 2002:a81:c64b:0:b0:62f:a56a:cee8 with SMTP id 00721157ae682-69ec54adf13mr3154657b3.3.1723411300470; Sun, 11 Aug 2024 14:21:40 -0700 (PDT) Date: Sun, 11 Aug 2024 15:21:29 -0600 In-Reply-To: <20240811212129.3074314-1-yuzhao@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240811212129.3074314-1-yuzhao@google.com> X-Mailer: git-send-email 2.46.0.76.ge559c4bf1a-goog Message-ID: <20240811212129.3074314-4-yuzhao@google.com> Subject: [PATCH mm-unstable v1 3/3] mm/hugetlb: use __GFP_COMP for gigantic folios From: Yu Zhao To: Andrew Morton , Muchun Song Cc: "Matthew Wilcox (Oracle)" , Zi Yan , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Yu Zhao Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Use __GFP_COMP for gigantic folios to greatly reduce not only the code but also the allocation and free time. LOC (approximately): -200, +50 Allocate and free 500 1GB hugeTLB memory without HVO by: time echo 500 >/sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages time echo 0 >/sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages Before After Alloc ~13s ~10s Free ~15s <1s The above magnitude generally holds for multiple x86 and arm64 CPU models. Signed-off-by: Yu Zhao --- include/linux/hugetlb.h | 9 +- mm/hugetlb.c | 244 ++++++++-------------------------------- 2 files changed, 50 insertions(+), 203 deletions(-) diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index 3100a52ceb73..98c47c394b89 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -896,10 +896,11 @@ static inline bool hugepage_movable_supported(struct = hstate *h) /* Movability of hugepages depends on migration support. */ static inline gfp_t htlb_alloc_mask(struct hstate *h) { - if (hugepage_movable_supported(h)) - return GFP_HIGHUSER_MOVABLE; - else - return GFP_HIGHUSER; + gfp_t gfp =3D __GFP_COMP | __GFP_NOWARN; + + gfp |=3D hugepage_movable_supported(h) ? GFP_HIGHUSER_MOVABLE : GFP_HIGHU= SER; + + return gfp; } =20 static inline gfp_t htlb_modify_alloc_mask(struct hstate *h, gfp_t gfp_mas= k) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 1c13e65ab119..691f63408d50 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1512,43 +1512,7 @@ static int hstate_next_node_to_free(struct hstate *h= , nodemask_t *nodes_allowed) ((node =3D hstate_next_node_to_free(hs, mask)) || 1); \ nr_nodes--) =20 -/* used to demote non-gigantic_huge pages as well */ -static void __destroy_compound_gigantic_folio(struct folio *folio, - unsigned int order, bool demote) -{ - int i; - int nr_pages =3D 1 << order; - struct page *p; - - atomic_set(&folio->_entire_mapcount, 0); - atomic_set(&folio->_large_mapcount, 0); - atomic_set(&folio->_pincount, 0); - - for (i =3D 1; i < nr_pages; i++) { - p =3D folio_page(folio, i); - p->flags &=3D ~PAGE_FLAGS_CHECK_AT_FREE; - p->mapping =3D NULL; - clear_compound_head(p); - if (!demote) - set_page_refcounted(p); - } - - __folio_clear_head(folio); -} - -static void destroy_compound_hugetlb_folio_for_demote(struct folio *folio, - unsigned int order) -{ - __destroy_compound_gigantic_folio(folio, order, true); -} - #ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE -static void destroy_compound_gigantic_folio(struct folio *folio, - unsigned int order) -{ - __destroy_compound_gigantic_folio(folio, order, false); -} - static void free_gigantic_folio(struct folio *folio, unsigned int order) { /* @@ -1569,38 +1533,52 @@ static void free_gigantic_folio(struct folio *folio= , unsigned int order) static struct folio *alloc_gigantic_folio(struct hstate *h, gfp_t gfp_mask, int nid, nodemask_t *nodemask) { - struct page *page; - unsigned long nr_pages =3D pages_per_huge_page(h); + struct folio *folio; + int order =3D huge_page_order(h); + bool retry =3D false; + if (nid =3D=3D NUMA_NO_NODE) nid =3D numa_mem_id(); - +retry: + folio =3D NULL; #ifdef CONFIG_CMA { int node; =20 - if (hugetlb_cma[nid]) { - page =3D cma_alloc(hugetlb_cma[nid], nr_pages, - huge_page_order(h), true); - if (page) - return page_folio(page); - } + if (hugetlb_cma[nid]) + folio =3D cma_alloc_folio(hugetlb_cma[nid], order, gfp_mask); =20 - if (!(gfp_mask & __GFP_THISNODE)) { + if (!folio && !(gfp_mask & __GFP_THISNODE)) { for_each_node_mask(node, *nodemask) { if (node =3D=3D nid || !hugetlb_cma[node]) continue; =20 - page =3D cma_alloc(hugetlb_cma[node], nr_pages, - huge_page_order(h), true); - if (page) - return page_folio(page); + folio =3D cma_alloc_folio(hugetlb_cma[node], order, gfp_mask); + if (folio) + break; } } } #endif + if (!folio) { + struct page *page =3D alloc_contig_pages(1 << order, gfp_mask, nid, node= mask); =20 - page =3D alloc_contig_pages(nr_pages, gfp_mask, nid, nodemask); - return page ? page_folio(page) : NULL; + if (!page) + return NULL; + + folio =3D page_folio(page); + } + + if (folio_ref_freeze(folio, 1)) + return folio; + + pr_warn("HugeTLB: unexpected refcount on PFN %lu\n", folio_pfn(folio)); + free_gigantic_folio(folio, order); + if (!retry) { + retry =3D true; + goto retry; + } + return NULL; } =20 #else /* !CONFIG_CONTIG_ALLOC */ @@ -1619,8 +1597,6 @@ static struct folio *alloc_gigantic_folio(struct hsta= te *h, gfp_t gfp_mask, } static inline void free_gigantic_folio(struct folio *folio, unsigned int order) { } -static inline void destroy_compound_gigantic_folio(struct folio *folio, - unsigned int order) { } #endif =20 /* @@ -1747,19 +1723,17 @@ static void __update_and_free_hugetlb_folio(struct = hstate *h, folio_clear_hugetlb_hwpoison(folio); =20 folio_ref_unfreeze(folio, 1); + INIT_LIST_HEAD(&folio->_deferred_list); =20 /* * Non-gigantic pages demoted from CMA allocated gigantic pages * need to be given back to CMA in free_gigantic_folio. */ if (hstate_is_gigantic(h) || - hugetlb_cma_folio(folio, huge_page_order(h))) { - destroy_compound_gigantic_folio(folio, huge_page_order(h)); + hugetlb_cma_folio(folio, huge_page_order(h))) free_gigantic_folio(folio, huge_page_order(h)); - } else { - INIT_LIST_HEAD(&folio->_deferred_list); + else folio_put(folio); - } } =20 /* @@ -2032,95 +2006,6 @@ static void prep_new_hugetlb_folio(struct hstate *h,= struct folio *folio, int ni spin_unlock_irq(&hugetlb_lock); } =20 -static bool __prep_compound_gigantic_folio(struct folio *folio, - unsigned int order, bool demote) -{ - int i, j; - int nr_pages =3D 1 << order; - struct page *p; - - __folio_clear_reserved(folio); - for (i =3D 0; i < nr_pages; i++) { - p =3D folio_page(folio, i); - - /* - * For gigantic hugepages allocated through bootmem at - * boot, it's safer to be consistent with the not-gigantic - * hugepages and clear the PG_reserved bit from all tail pages - * too. Otherwise drivers using get_user_pages() to access tail - * pages may get the reference counting wrong if they see - * PG_reserved set on a tail page (despite the head page not - * having PG_reserved set). Enforcing this consistency between - * head and tail pages allows drivers to optimize away a check - * on the head page when they need know if put_page() is needed - * after get_user_pages(). - */ - if (i !=3D 0) /* head page cleared above */ - __ClearPageReserved(p); - /* - * Subtle and very unlikely - * - * Gigantic 'page allocators' such as memblock or cma will - * return a set of pages with each page ref counted. We need - * to turn this set of pages into a compound page with tail - * page ref counts set to zero. Code such as speculative page - * cache adding could take a ref on a 'to be' tail page. - * We need to respect any increased ref count, and only set - * the ref count to zero if count is currently 1. If count - * is not 1, we return an error. An error return indicates - * the set of pages can not be converted to a gigantic page. - * The caller who allocated the pages should then discard the - * pages using the appropriate free interface. - * - * In the case of demote, the ref count will be zero. - */ - if (!demote) { - if (!page_ref_freeze(p, 1)) { - pr_warn("HugeTLB page can not be used due to unexpected inflated ref c= ount\n"); - goto out_error; - } - } else { - VM_BUG_ON_PAGE(page_count(p), p); - } - if (i !=3D 0) - set_compound_head(p, &folio->page); - } - __folio_set_head(folio); - /* we rely on prep_new_hugetlb_folio to set the hugetlb flag */ - folio_set_order(folio, order); - atomic_set(&folio->_entire_mapcount, -1); - atomic_set(&folio->_large_mapcount, -1); - atomic_set(&folio->_pincount, 0); - return true; - -out_error: - /* undo page modifications made above */ - for (j =3D 0; j < i; j++) { - p =3D folio_page(folio, j); - if (j !=3D 0) - clear_compound_head(p); - set_page_refcounted(p); - } - /* need to clear PG_reserved on remaining tail pages */ - for (; j < nr_pages; j++) { - p =3D folio_page(folio, j); - __ClearPageReserved(p); - } - return false; -} - -static bool prep_compound_gigantic_folio(struct folio *folio, - unsigned int order) -{ - return __prep_compound_gigantic_folio(folio, order, false); -} - -static bool prep_compound_gigantic_folio_for_demote(struct folio *folio, - unsigned int order) -{ - return __prep_compound_gigantic_folio(folio, order, true); -} - /* * Find and lock address space (mapping) in write mode. * @@ -2159,7 +2044,6 @@ static struct folio *alloc_buddy_hugetlb_folio(struct= hstate *h, */ if (node_alloc_noretry && node_isset(nid, *node_alloc_noretry)) alloc_try_hard =3D false; - gfp_mask |=3D __GFP_COMP|__GFP_NOWARN; if (alloc_try_hard) gfp_mask |=3D __GFP_RETRY_MAYFAIL; if (nid =3D=3D NUMA_NO_NODE) @@ -2206,48 +2090,14 @@ static struct folio *alloc_buddy_hugetlb_folio(stru= ct hstate *h, return folio; } =20 -static struct folio *__alloc_fresh_hugetlb_folio(struct hstate *h, - gfp_t gfp_mask, int nid, nodemask_t *nmask, - nodemask_t *node_alloc_noretry) -{ - struct folio *folio; - bool retry =3D false; - -retry: - if (hstate_is_gigantic(h)) - folio =3D alloc_gigantic_folio(h, gfp_mask, nid, nmask); - else - folio =3D alloc_buddy_hugetlb_folio(h, gfp_mask, - nid, nmask, node_alloc_noretry); - if (!folio) - return NULL; - - if (hstate_is_gigantic(h)) { - if (!prep_compound_gigantic_folio(folio, huge_page_order(h))) { - /* - * Rare failure to convert pages to compound page. - * Free pages and try again - ONCE! - */ - free_gigantic_folio(folio, huge_page_order(h)); - if (!retry) { - retry =3D true; - goto retry; - } - return NULL; - } - } - - return folio; -} - static struct folio *only_alloc_fresh_hugetlb_folio(struct hstate *h, gfp_t gfp_mask, int nid, nodemask_t *nmask, nodemask_t *node_alloc_noretry) { struct folio *folio; =20 - folio =3D __alloc_fresh_hugetlb_folio(h, gfp_mask, nid, nmask, - node_alloc_noretry); + folio =3D hstate_is_gigantic(h) ? alloc_gigantic_folio(h, gfp_mask, nid, = nmask) : + alloc_buddy_hugetlb_folio(h, gfp_mask, nid, nmask, node_alloc_noretry); if (folio) init_new_hugetlb_folio(h, folio); return folio; @@ -2265,7 +2115,8 @@ static struct folio *alloc_fresh_hugetlb_folio(struct= hstate *h, { struct folio *folio; =20 - folio =3D __alloc_fresh_hugetlb_folio(h, gfp_mask, nid, nmask, NULL); + folio =3D hstate_is_gigantic(h) ? alloc_gigantic_folio(h, gfp_mask, nid, = nmask) : + alloc_buddy_hugetlb_folio(h, gfp_mask, nid, nmask, NULL); if (!folio) return NULL; =20 @@ -2549,9 +2400,8 @@ struct folio *alloc_buddy_hugetlb_folio_with_mpol(str= uct hstate *h, =20 nid =3D huge_node(vma, addr, gfp_mask, &mpol, &nodemask); if (mpol_is_preferred_many(mpol)) { - gfp_t gfp =3D gfp_mask | __GFP_NOWARN; + gfp_t gfp =3D gfp_mask & ~(__GFP_DIRECT_RECLAIM | __GFP_NOFAIL); =20 - gfp &=3D ~(__GFP_DIRECT_RECLAIM | __GFP_NOFAIL); folio =3D alloc_surplus_hugetlb_folio(h, gfp, nid, nodemask); =20 /* Fallback to all nodes if page=3D=3DNULL */ @@ -3333,6 +3183,7 @@ static void __init hugetlb_folio_init_tail_vmemmap(st= ruct folio *folio, for (pfn =3D head_pfn + start_page_number; pfn < end_pfn; pfn++) { struct page *page =3D pfn_to_page(pfn); =20 + __ClearPageReserved(folio_page(folio, pfn - head_pfn)); __init_single_page(page, pfn, zone, nid); prep_compound_tail((struct page *)folio, pfn - head_pfn); ret =3D page_ref_freeze(page, 1); @@ -3949,21 +3800,16 @@ static long demote_free_hugetlb_folios(struct hstat= e *src, struct hstate *dst, continue; =20 list_del(&folio->lru); - /* - * Use destroy_compound_hugetlb_folio_for_demote for all huge page - * sizes as it will not ref count folios. - */ - destroy_compound_hugetlb_folio_for_demote(folio, huge_page_order(src)); + + split_page_owner(&folio->page, huge_page_order(src), huge_page_order(dst= )); + pgalloc_tag_split(&folio->page, 1 << huge_page_order(src)); =20 for (i =3D 0; i < pages_per_huge_page(src); i +=3D pages_per_huge_page(d= st)) { struct page *page =3D folio_page(folio, i); =20 - if (hstate_is_gigantic(dst)) - prep_compound_gigantic_folio_for_demote(page_folio(page), - dst->order); - else - prep_compound_page(page, dst->order); - set_page_private(page, 0); + page->mapping =3D NULL; + clear_compound_head(page); + prep_compound_page(page, dst->order); =20 init_new_hugetlb_folio(dst, page_folio(page)); list_add(&page->lru, &dst_list); --=20 2.46.0.76.ge559c4bf1a-goog