Date: Sat, 17 Jan 2009 14:45:07 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-7@freebsd.org Subject: svn commit: r187364 - in stable/7/sys: . contrib/pf dev/cxgb kern vm Message-ID: <200901171445.n0HEj7pa045370@svn.freebsd.org>
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Author: kib Date: Sat Jan 17 14:45:07 2009 New Revision: 187364 URL: http://svn.freebsd.org/changeset/base/187364 Log: MFC r186719: Extend the struct vm_page wire_count to u_int to avoid the overflow of the counter, that may happen when too many sendfile(2) calls are being executed with this vnode. To keep the size of the struct vm_page and offsets of the fields accessed by out-of-tree modules, swap the types and locations of the wire_count and cow fields. Add safety checks to detect cow overflow and force fallback to the normal copy code for zero-copy sockets. Modified: stable/7/sys/ (props changed) stable/7/sys/contrib/pf/ (props changed) stable/7/sys/dev/cxgb/ (props changed) stable/7/sys/kern/uipc_cow.c stable/7/sys/vm/vm_page.c stable/7/sys/vm/vm_page.h Modified: stable/7/sys/kern/uipc_cow.c ============================================================================== --- stable/7/sys/kern/uipc_cow.c Sat Jan 17 14:37:54 2009 (r187363) +++ stable/7/sys/kern/uipc_cow.c Sat Jan 17 14:45:07 2009 (r187364) @@ -129,7 +129,11 @@ socow_setup(struct mbuf *m0, struct uio * set up COW */ vm_page_lock_queues(); - vm_page_cowsetup(pp); + if (vm_page_cowsetup(pp) != 0) { + vm_page_unhold(pp); + vm_page_unlock_queues(); + return (0); + } /* * wire the page for I/O Modified: stable/7/sys/vm/vm_page.c ============================================================================== --- stable/7/sys/vm/vm_page.c Sat Jan 17 14:37:54 2009 (r187363) +++ stable/7/sys/vm/vm_page.c Sat Jan 17 14:45:07 2009 (r187364) @@ -103,6 +103,7 @@ __FBSDID("$FreeBSD$"); #include <sys/systm.h> #include <sys/lock.h> #include <sys/kernel.h> +#include <sys/limits.h> #include <sys/malloc.h> #include <sys/mutex.h> #include <sys/proc.h> @@ -2003,13 +2004,16 @@ vm_page_cowclear(vm_page_t m) */ } -void +int vm_page_cowsetup(vm_page_t m) { mtx_assert(&vm_page_queue_mtx, MA_OWNED); + if (m->cow == USHRT_MAX - 1) + return (EBUSY); m->cow++; pmap_remove_write(m); + return (0); } #include "opt_ddb.h" Modified: stable/7/sys/vm/vm_page.h ============================================================================== --- stable/7/sys/vm/vm_page.h Sat Jan 17 14:37:54 2009 (r187363) +++ stable/7/sys/vm/vm_page.h Sat Jan 17 14:45:07 2009 (r187364) @@ -111,12 +111,12 @@ struct vm_page { vm_paddr_t phys_addr; /* physical address of page */ struct md_page md; /* machine dependant stuff */ uint8_t queue; /* page queue index */ - int8_t segind; + int8_t segind; u_short flags; /* see below */ uint8_t order; /* index of the buddy queue */ uint8_t pool; - u_short wire_count; /* wired down maps refs (P) */ - u_int cow; /* page cow mapping count */ + u_short cow; /* page cow mapping count */ + u_int wire_count; /* wired down maps refs (P) */ short hold_count; /* page hold count */ u_short oflags; /* page flags (O) */ u_char act_count; /* page usage count */ @@ -346,7 +346,7 @@ void vm_page_zero_invalid(vm_page_t m, b void vm_page_free_toq(vm_page_t m); void vm_page_zero_idle_wakeup(void); void vm_page_cowfault (vm_page_t); -void vm_page_cowsetup (vm_page_t); +int vm_page_cowsetup(vm_page_t); void vm_page_cowclear (vm_page_t); /*
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