From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 9CF1E3857C68; Mon, 27 Nov 2023 19:47:05 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 9CF1E3857C68 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1701114425; bh=xzz81N0uymoqmyBzs93p5rN4KWExG4dvdVJPPuEoU/U=; h=From:To:Subject:Date:In-Reply-To:References:From; b=I37+TUMJGo/JywshIVfnPDooy33duD0/NSFG3ep7Vbik7iX9QTxXp7Ty2YBBR6r4L dz56yc2LYjRqSMOfMUDWB2wj7Ba/CR5//NrTuEU7pSXreSMzvmye6HuZKhJhIuUH9d q3tfdvJyS1PZzEnhtbZ9gmiMqyQJgH/a4xFbjCE8= From: "jyescas at google dot com" To: glibc-bugs@sourceware.org Subject: [Bug dynamic-link/31076] Extra struct vm_area_struct with ---p created when PAGE_SIZE < max-page-size Date: Mon, 27 Nov 2023 19:47:05 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: glibc X-Bugzilla-Component: dynamic-link X-Bugzilla-Version: unspecified X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: jyescas at google dot com X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P2 X-Bugzilla-Assigned-To: unassigned at sourceware dot org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://sourceware.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 List-Id: https://sourceware.org/bugzilla/show_bug.cgi?id=3D31076 --- Comment #12 from Juan Yescas --- (In reply to Florian Weimer from comment #5) > I don't see how a 152 byte struct results in 30 MB of unreclaimable kernel > memory. Wouldn't that need ~200,000 instances? That seems really large. > I've only got ~70,000 lines in /proc/*/maps on this desktop system, and n= ot > all these mappings will exhibit this issue. >=20 When we compile all the shared libraries in the system with -Wl,-z,max-page-size=3D65536 and use 4k page size kernel, for every PT_LOAD segment (except the last) loaded in memory, there will be a vm_area_struct = with ---p permissions. In mobile devices we have seen an increased of 120K vm_area_structs due -Wl,-z,max-page-size=3D65536. There used to be 40K vm_area_structs. This is= an increase of ~18MB (120K * 152). --=20 You are receiving this mail because: You are on the CC list for the bug.=