From nobody Thu Oct 16 23:16:15 2025 X-Original-To: dev-commits-src-main@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4cnkNH60Czz6DJyB; Thu, 16 Oct 2025 23:16:15 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R12" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4cnkNH5SVQz3x7Z; Thu, 16 Oct 2025 23:16:15 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1760656575; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=1cl4WYBxhpKohU74WS5uO0Qut9ZHKitjgcqxAtqhD0I=; b=eEOOrZgxmg0mcASPIKnUTgBvTi4lET6DHgZJsRnp4naegGFDezjgEqRh8e4XqZD78dVmU4 X6t1Bm1Q6RRaA/mPRlh2hmRYxNN0cMm3iGiAMcvfZBVt7lgdwgPww3Fa0yS+TPsnwxiGNz Aw15ENT5VtADOQEOVWVgFHwjAy1HvfDD7arbHWsHXJ2zeiwSxguNiBMaafu2iX9qI23xvE qusSjgZiBZXJk5bET3yKtyonC4jVPkw4K6i4eiB5o6v/5q5ql1ffcvO1nkVWIGQGQXW1G9 J3gJTf8nA2oz/lN6qBDQT68pwQ3Vh5vTSz/xLdEFAM3GWKCFSYn8+o+MSIJu9Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1760656575; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=1cl4WYBxhpKohU74WS5uO0Qut9ZHKitjgcqxAtqhD0I=; b=t99BZvqVvZk6Advza3BPJPSldIxwxcP/WUYejEYrf29zo7SZnsd/Me71Vy+P6S3Eie4Fdo EiS1JpLC/X5gw+A9KDQ2XgZn5tGbH8Tm05B2P999+fX/61BDXA14CaGBLMieN+9vqEYD6p qsX5/vh3j/QPn4SIPo+XExvt/wCLyiNg3hNQxm0dX+fh87XaSUbQ28+yJQvniyafDUZQYz t8INAxP1orJZ+qfAdbN97lr5aMi8hMEfwbhueGjZQ7o4cwnG/3AA0fWTc/NFwfzpFuPigI JY3e0Qpse9eZM6/r+JiYumxwW/0UhK/1eBVvOYGiVbAbgrO+SpNt8WEO0mIGaA== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1760656575; a=rsa-sha256; cv=none; b=LF3HvG+bdypV5i2MNW9id+LbGfg/26IX62Q/bRPROJT0VrOCx9iqmJYkcD7DWtf3zcga0+ 1lOWgpnAxJ9WmrL7K9mgaYPtM+Oi990kiQvSHDcxaV8zoqeZQxtkXofQVHzXdyUk89MsdQ 1Kvun3aJCTOfNfcmvTmLyt4b6VkNDLip6txzni8FV0y1id9wqHKF23sCdecTC7yAp/LR7G dEoAYmimsm7f0xgGOu6G4iesY2KlxMpuTT3fbHNxUOTCeKeM2GGZeCdfGZDKhEpUhAqwmh fmY5hWlIAyaLq23Tog89ZmU/fT2QXdWp9YtC1zxlwzT4J4t6f11p+80ZLCbRuw== ARC-Authentication-Results: i=1; mx1.freebsd.org; none Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 4cnkNH4zsYzDJ3; Thu, 16 Oct 2025 23:16:15 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.18.1/8.18.1) with ESMTP id 59GNGFpd075058; Thu, 16 Oct 2025 23:16:15 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.18.1/8.18.1/Submit) id 59GNGFfj075055; Thu, 16 Oct 2025 23:16:15 GMT (envelope-from git) Date: Thu, 16 Oct 2025 23:16:15 GMT Message-Id: <202510162316.59GNGFfj075055@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: Mark Johnston Subject: git: 3b9b64457676 - main - vm: Fix iterator usage in vm_thread_stack_create() List-Id: Commit messages for the main branch of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-main List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: dev-commits-src-main@freebsd.org Sender: owner-dev-commits-src-main@FreeBSD.org MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: markj X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: 3b9b64457676561b8de2bec7c94c561bbd807b0c Auto-Submitted: auto-generated The branch main has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=3b9b64457676561b8de2bec7c94c561bbd807b0c commit 3b9b64457676561b8de2bec7c94c561bbd807b0c Author: Mark Johnston AuthorDate: 2025-10-16 23:12:54 +0000 Commit: Mark Johnston CommitDate: 2025-10-16 23:13:34 +0000 vm: Fix iterator usage in vm_thread_stack_create() After commit 7a79d0669761 we no longer hold the VM object lock when initializing or advancing the domainset iterator in vm_thread_stack_create(). We could lift the lock out of vm_thread_stack_back() but that poses complications since we cannot allocate KVA with a VM object lock held. Instead of overridding the object's iterator, just borrow that of the current thread. Kernel stacks are basically always allocated with a DOMAINSET_POLICY_PREFER policy, so it's not very important to maintain a global iterator for round-robin allocation. As a part of this, fix up flag handling: make sure we handle M_NOWAIT/M_WAITOK from the caller. Delete a comment in vm_thread_new() which refers to a non-existent consideration (stack swapping has been removed). I suspect vm_thread_new() can use M_WAITOK but opted not to make that change here. Reported by: olce Reviewed by: olce, alc, kib Fixes: 7a79d0669761 ("vm: improve kstack_object pindex calculation to avoid pindex holes") MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D52982 --- sys/vm/vm_glue.c | 24 ++++++++---------------- 1 file changed, 8 insertions(+), 16 deletions(-) diff --git a/sys/vm/vm_glue.c b/sys/vm/vm_glue.c index e0f1807a1b32..18d789c59281 100644 --- a/sys/vm/vm_glue.c +++ b/sys/vm/vm_glue.c @@ -441,19 +441,16 @@ vm_thread_kstack_arena_release(void *arena, vmem_addr_t addr, vmem_size_t size) * Create the kernel stack for a new thread. */ static vm_offset_t -vm_thread_stack_create(struct domainset *ds, int pages) +vm_thread_stack_create(struct domainset *ds, int pages, int flags) { vm_page_t ma[KSTACK_MAX_PAGES]; struct vm_domainset_iter di; - int req = VM_ALLOC_NORMAL; - vm_object_t obj; + int req; vm_offset_t ks; int domain, i; - obj = vm_thread_kstack_size_to_obj(pages); - if (vm_ndomains > 1) - obj->domain.dr_policy = ds; - vm_domainset_iter_page_init(&di, obj, 0, &domain, &req); + vm_domainset_iter_policy_init(&di, ds, &domain, &flags); + req = malloc2vm_flags(flags); do { /* * Get a kernel virtual address for this thread's kstack. @@ -480,7 +477,7 @@ vm_thread_stack_create(struct domainset *ds, int pages) vm_page_valid(ma[i]); pmap_qenter(ks, ma, pages); return (ks); - } while (vm_domainset_iter_page(&di, obj, &domain, NULL) == 0); + } while (vm_domainset_iter_policy(&di, &domain) == 0); return (0); } @@ -532,15 +529,9 @@ vm_thread_new(struct thread *td, int pages) ks = 0; if (pages == kstack_pages && kstack_cache != NULL) ks = (vm_offset_t)uma_zalloc(kstack_cache, M_NOWAIT); - - /* - * Ensure that kstack objects can draw pages from any memory - * domain. Otherwise a local memory shortage can block a process - * swap-in. - */ if (ks == 0) ks = vm_thread_stack_create(DOMAINSET_PREF(PCPU_GET(domain)), - pages); + pages, M_NOWAIT); if (ks == 0) return (0); @@ -660,7 +651,8 @@ kstack_import(void *arg, void **store, int cnt, int domain, int flags) ds = DOMAINSET_PREF(domain); for (i = 0; i < cnt; i++) { - store[i] = (void *)vm_thread_stack_create(ds, kstack_pages); + store[i] = (void *)vm_thread_stack_create(ds, kstack_pages, + flags); if (store[i] == NULL) break; }